EvolutionTim WhitehouseBrennan RayKevin BrittAJ Walters

Chapter 22!

Main Idea 1

• Before Darwin, there were many differing views on how evolution occurred.

1. The first ideas about evolution was that life might change gradually over time (Greek philosphers)

2. Aristotle saw species as fitting a certain spot on a “ladder” which he called the scala naturae,and was perfect and permenant.

3. Some people who were religious believed that since God made all the species, they were perfect and didn’t change at all.

4. Carolus Linnaeus created a binomial system for naming species.

Main Idea 2

• Darwin got many of his ideasfrom the work of paleontology (the study of fossils)

1. Darwin looked at how older fossils had changed from newer fossils.2. Catastrophism led to the ideas about mass extinction, which Darwin

never figured out, but is still important to know.3. Darwin also looked at uniformitarianism, which applied loosely to his

ideas on evolution.

Main Idea 3

• Darwin’s voyage on the HMS Beagle helped him form his ideas on evolution.

1. Darwin sailed around the world while aboard the Beagle2. Darwin noted that plants and animals were well suited for their

environment.3. Darwin's most famous endeavor was on the Galapagos islands, where he

studied several kinds of finches, which were suited to do different things according to their food source.

Main Idea 4

• Darwin came up with the concept of natural selection.

1. Darwin saw many adoptions in the different animals he saw.2. Hypothesized that species arise from older species after having many

adoptions, and species got adoptions that better suited them to their environment.

3. Wrote all his ideas on this in his book: On the Origin of Species by Means of Natural Selection (commonly known as The Origin of Species)

Main Idea 5

• Descent with Modification

1. Darwin never used the term Evolution, even though it was the last word in his book, to describe his “Descent with Modification”

2. Thought there was a common ancestor for all organisms.3. Saw evolution as a tree with points of evolution breaking off from the

main branch.

Main Idea 6

• Artificial Selection

1. Humans can cause this, we call it selective breeding.2. Made observations of nature that traits are inherited from an organisms

parents.3. Darwin hypothesized an important connection that organism’s could

“overproduce”, or have more offspring than their environment could handle.

Main Idea 7

• You can observe evolution directly.

1. Separation of species can cause evolution to occur as organisms adapt to their new environment.

2. An example of direct observations is the experiment with the guppies (Page 460)

3. Another example of ongoing natural selection is HIV becoming drug-resistant.

Main Idea 8

• We can “see” evolution in fossil records.

1. Fossils show that past organisms differed from present-day organisms.2. Fossils show the gradual changes in organisms over time.3. These predictions of changes based on fossils can be predicted by using

radioactive dating techniques.

Main Idea 9

• Studying Homology helps us “see” evolution.

1. Organisms can have characteristics that have underlying similarities but have different functions.

2. These structures are called homologous structures.3. Many of the most intriguing homologies concern “leftover” structures

of marginal importance to the organism.

Main Idea 10

• Biogeography is evidence of evolution

1. This is the geographic distribution of species.2. Sometimes caused by continental drift.3. Explains a little about endemic species.

VOCAB!!!SO EXCITING!!!!

Evolution

Descent with modification.

Fossils

• The remains or traces of organisms from the past.

Strata

• Superimposed layers of sedimentary rock.

Paleontology

• The study of fossils.

Catastrophism

• The principle that events in the past occurred suddenly and were caused by mechanisms different from those operating in the present.

Uniformitarianism

• Mechanisms of change are constant over time.

Adaptations

• Characteristics of organisms that enhance their survival and reproduction in specific enviroments.

Natural Selection

• A process in which individuals with certain inherited traits leave more offspring than individuals with other traits.

Artificial Selection

• When humans modify other species over many generations by selecting and breeding individuals that possess desired traits.

Homology

• Similarities between species resulting from having a common ancestor.

Homologous Structures

• Variations on a structural theme that was present in species’ common ancestor.

Vestigial Structures

• Remnants of features that served important functions on the organism's ancestry.

Evolutionary Tree

• A diagram that reflects evolutionary relationships among groups of organisms.

Convergent Evolution

• Independent evolution of similar features in different lineages.

Analogous

• Resemblances in species due to convergent evolution.

Biogeography

• The geographic distribution of species.

Continental Drift

• The slow movement of Earth’s continents over time.

Pangaea

• The single large continent that existed on Earth 250 million years ago.

Endemic

• When species are found nowhere else in the world.

Picture Time!!!!!!

Layers of Strata

The finches Darwin studied

Evolutionary Tree!Species A

Species B

Species C

Species D

C

B

A

A Common ancestor to all four species.

B Common ancestor to species A and B

C Common ancestor to species C and D

Homologous Structures

Question Time!!!!

Question 1

• The similar structures in mamamlian forlimbs is an example of…?

a) Vestigial Structures.b) Transitional Structuresc) Homologous Structuresd) Convergent Evolutione) Balancing Selection

Question 1

• The similar structures in mamamlian forlimbs is an example of…?

a) Vestigial Structures.b) Transitional Structuresc) Homologous Structuresd) Convergent Evolutione) Balancing Selection

Question 2

• Islands will generally have many species of plants and animals that are…?

a) Weird lookingb) Vestigialc) Repulsivaryd) Endemice) Heterozygotes

Question 2

• Islands will generally have many species of plants and animals that are…?

a) Weird lookingb) Vestigialc) Repulsivaryd) Endemice) Heterozygotes

Question 3

• Camouflage is an example of…

a) Evolutionary Adadptionsb) Cool Traitsc) Uniformitarianismd) Homologye) Relative Fitness

Question 3

• Camouflage is an example of…

a) Evolutionary Adadptionsb) Cool Traitsc) Uniformitarianismd) Homologye) Relative Fitness

Question 4

• Biogeography is evidence for what?

a) Evolutionb) Convergent Evolutionc) Catastrophismd) Uniformitarianisme) Fossils

Question 4

• Biogeography is evidence for what?

a) Evolutionb) Convergent Evolutionc) Catastrophismd) Uniformitarianisme) Fossils

Question 5

• Each branch represents what in an evolutionary tree?

a) A common ancestorb) A common traitc) A convergent evolutiond) A death of a speciese) A new kingdom of animals

Question 5

• Each branch represents what in an evolutionary tree?

a) A common ancestorb) A common traitc) A convergent evolutiond) A death of a speciese) A new kingdom of animals

Question 6

• Charles Darwin is most famous for being the father of what branch of science?

a) Paleontologyb) Evolutionc) Atomic engineeringd) Zoology e) Genetics

Question 6

• Charles Darwin is most famous for being the father of what branch of science?

a) Paleontologyb) Evolutionc) Atomic engineeringd) Zoology e) Genetics

Question 7

• Aristotle thought of life-forms as belonging to what?

a) Breeds of fishb) Rungs on a ladderc) Types of colorsd) Steps in a staircasee) Certain body parts of Mother Earth

Question 7

• Aristotle thought of life-forms as belonging to what?

a) Breeds of fishb) Rungs on a ladderc) Types of colorsd) Steps in a staircasee) Certain body parts of Mother Earth

Question 8

• Carolus Linnaeus is famous for developing what?

a) A new way to name speciesb) The ideas of catastrophismc) The Scala Naturaed) Evolutionary ideas before Darwine) The Periodic Table

Question 8

• Carolus Linnaeus is famous for developing what?

a) A new way to name speciesb) The ideas of catastrophismc) The Scala Naturaed) Evolutionary ideas before Darwine) The Periodic Table

Question 9

• Darwin noticed that species in tropics were well suited to their…?

a) Enviroments.b) Mating rituals.c) Taste in food.d) Mates.e) Weather conditions.

Question 9

• Darwin noticed that species in tropics were well suited to their…?

a) Environments.b) Mating rituals.c) Taste in food.d) Mates.e) Weather conditions.

Question 10

• Darwin’s famous book was called what?

a) Evolution for Dummiesb) Of Evolution and Speciesc) What Happened to the Dinosaurs?d) On the Origins of Species by Means of Natural

Selectione) On the Origins of Species by Means of Evolution

Question 10

• Darwin’s famous book was called what?

a) Evolution for Dummiesb) Of Evolution and Speciesc) What Happened to the Dinosaurs?d) On the Origins of Species by Means of Natural

Selectione) On the Origins of Species by Means of Evolution

Question 11

• Darwin never used Evolution in his book, instead he used what?

a) Gradual change over timeb) New looksc) Descent with changed) Descent with modificationse) Change and modification

Question 11

• Darwin never used Evolution in his book, instead he used what?

a) Gradual change over timeb) New looksc) Descent with changed) Descent with modificationse) Change and modification

That’s All Folks!

Chapter 23!

Main Idea 1

• Evolution only occurs through entire populations.

1. Common misconception that organisms evolve.2. Gradual changes occur throughout a population over time.3. The overall evolution of populations is called microevolution (evolutions

smallest scale)

Main Idea 2

• Genetic variations causes unique genotypes/phenotypes.

1. Many of these variations occur at the molecular level.2. Variations are either discrete or quantitative.3. There can be variation between isolated populations of the same species.

Main Idea 3

• Mutations

1. Mutations are the ultimate source of new alleles.2. We cannot accurately predict mutations, they occur randomly.3. These mutations can have large impacts or small impacts on the

organism. It depends on which genes are altered and how.

SIDE NOTE!!!!

• Organisms that reproduce sexually have genetic variation within the population mainly due to the unique combinations of parents genes that the organisms receive.

Main Idea 4

• The Hardy-Weinberg Principle

1. Organisms are not evolving if they meet certain requirements. 2. Requirements: A. No mutations B. Random mating C.

No Natural Selection D. Extremely large population size E. No gene flow

3. Equation written as p²+ 2pq+q²=1

Main Idea 5

• Genetic Drift

1. The founder and bottleneck effect both cause genetic drift.2. Caused by random events3. Isn’t guaranteed to occur, because happens due to the events being

random.

Main Idea 6

• Gene Flow affects allele frequencies

1. Caused by immigration and emigration.2. Reduces genetic difference between populations.3. If gene flow is extensive enough, neighboring populations could merge

into a single population.

Main Idea 7

• Natural selection depends on who is best suited for their environment.

1. There can be directional, disruptive, or stabilizing selection occurring.2. Relative fitness plays important part in natural selection3. Adoptions for its environment help an organism to survive and

reproduce.

Main Idea 8

• Sexual Selection plays a large role in evolution.

1. This process can lead to sexual dimorphism in a species/population.2. There is both intersexual (mate choice) and intrasexual selection.3. Leads to males wanting what are correlated as “good genes”.

Main Idea 9

• Evolution cannot remove all unfavorable genes.

1. Recessive alleles can be carried by heterozygous individuals.2. Balancing Selection can occur in populations3. Sometimes there is a heterozygous advantage, compared to a recessive

or a dominant advantage.4. Sometimes, the fitness of a phenotype declines if that genotype is too

common in a population.

Main Idea 10

• Natural Selection Cannot form a perfect organism.

1. Selection can act only on existing variations.2. Evolution is limited by historical constraints.3. Adoptions are often compromises4. Chance, natural selection, and the environment interact.

Vocab!!!!!

Average Heterozygosity

• The average percent of loci that are heterozygous.

Geographic Variation

• Differences in the genetic composition of separate populations.

Cline

• A graded change in a character along a geographic axis.

Mutation

• A change in the nucleotide sequence of an organism’s DNA.

Population

• A group of individuals of the same species that live in the same area and interbreed.

Gene Pool

• All of the alleles for all the loci in all individuals of the population.

The Hardy-Weinberg Principle

• A hypothetical situation of a population that is not evolving.

Hardy-Weinberg Equilibrium

• When a gene pool meets all requirements of a Hardy-Weinberg Principle and are not evolving.

Genetic Drift

• A process in which chance events cause unpredictable fluctuations in allele frequencies from one generation to the next. Effects of this are more pronounced in small populations.

Founder Effect

• When a few individuals from a population are isolated, and they establish a new population whose genes are different than those of the original population.

Bottleneck Effect

• A sudden change in the environment, such as a fire or flood, may drastically reduce the size of a population, causing the new population to have a small amounts of alleles.

Gene Flow

• The transfer of alleles into or out of a population due to the movement of fertile individuals or their gametes.

Relative Fitness

• The contribution an individual makes to the gene pool of the next generation, relative to the fitness of other individuals.

Directional Selection

• Occurs when conditions favor individuals exhibiting one extreme of a phenotypic range, thereby shifting the frequency curve for the phenotypic character in one direction or the other.

Disruptive Selection

• Occurs when conditions favor individuals at both extremes of a phenotypic range over individuals with intermediate phenotypes.

Stabilizing Selection

• Acts against both extreme phenotypes and favors intermediate variants.

Sexual Selection

• A form of natural selection in which individuals with certain inherited characteristics are more likely than other individuals to obtain mates.

Sexual Dimorphism

• Marked differences between the two sexes in secondary sexual characteristics, which are not directly associated with reproduction or survival.

Intrasexual Selection

• Selection within the same sex, individuals of one sex compete directly for mates of the opposite sex.

Intersexual Selection

• Called mate choice, individuals of one sex (usually the females) are choosy in selecting their mates from the other sex.

Balancing Selection

• When natural selection maintains two or more forms in a population.

Heterozygote Selection

• An environment where individuals with heterozygotic traits have better fitness than do both kinds homozygotes.

Frequency-Dependent Selection

• The fitness of a phenotype declines if it becomes too common in the population.

Neutral Variation

• Genetic variation that does not appear to provide a selective advantage or disadvantage.

Geographic VariationCan you tell me who this is? And who is this?

•This shows geographic variation as we see the facial differences between people of Chinese and African American descent.

Genetic Drift

Because the foot squashed two bugs randomly, there is only one green bug left in the population.

Bottleneck Effect

The bottle above only pours out five random marbles, which represent the different alleles, and these alleles are random and will be the gene pool of the new population.

Sexual Dimorphism

QUESTIONS!!!

Question 1

• Which of these conditions are one of the Conditions of the Hardy-Weinderg Principle?

a) Even male to female ratio.b) Natural selection occurs.c) No natural selection occurs.d) Non-random mating.e) Exponential gene flow.

Question 1

• Which of these conditions are one of the Conditions of the Hardy-Weinderg Principle?

a) Even male to female ratio.b) Natural selection occurs.c) No natural selection occurs.d) Non-random mating.e) Exponential gene flow.

Question 2

• Which are two examples of genetic drift (select two answers from the list)?

a) Bottleneck Effectb) Hardy-Weinberg Effectc) Isolation Effectd) Founder Effecte) Catastrophism

Question 2

• Which are two examples of genetic drift (select two answers from the list)?

a) Bottleneck Effectb) Hardy-Weinberg Effectc) Isolation Effectd) Founder Effecte) Catastrophism

Question 3

• Which of the following is the smallest scale of evolution?

a) Macroevolutionb) Smallvolutionc) Microevolutiond) Minilutione) Evolution of Species

Question 3

• Which of the following is the smallest scale of evolution?

a) Macroevolutionb) Smallvolutionc) Microevolutiond) Minilutione) Evolution of Species

Question 4

• Where does most of the genetic variation in a population that reproduces sexually come from?

a) The random mating.b) Random combinations of their parents features.c) Random combination alleles received.d) Asexual reproduction of ancestors.e) Geographic Variations

Question 4

• Where does most of the genetic variation in a population that reproduces sexually come from?

a) The random mating.b) Random combinations of their parents features.c) Random combination alleles received.d) Asexual reproduction of ancestors.e) Geographic Variations

Question 5

• In which population is genetic drift most significant?

a) Isolated large populations.b) Large populations with gene flow.c) Small populations.d) Interbreeding populations.e) All large populations

Question 5

• In which population is genetic drift most significant?

a) Isolated large populations.b) Large populations with gene flow.c) Small populations.d) Interbreeding populations.e) All large populations

Question 6

• If an environment supports an organism with intermediate variations, it is experiencing…?

a) Directional Selectionb) Disruptive Evolutionc) Stabilizing Selectiond) Sexual Selectione) General Evolution

Question 6

• If an environment supports an organism with intermediate variations, it is experiencing…?

a) Directional Selectionb) Disruptive Evolutionc) Stabilizing Selectiond) Sexual Selectione) General Evolution

Question 7

• Intrasexual Selection is…?

a) When males choose the females.b) When females choose the males.c) When females look at males features to decide a

mate.d) When one sex challenges individuals of the same

sex for the rights to mate.e) Sexual Dimorphism.

Question 7

• Intrasexual Selection is…?

a) When males choose the females.b) When females choose the males.c) When females look at males features to decide a

mate.d) When one sex challenges individuals of the same

sex for the rights to mate.e) Sexual Dimorphism.

Question 8

• During a heterozygote advantage you will have…?

a) Homozygotes dying in large amounts.b) Heterozygotes having better fitness.c) Homozygous individuals not being able to mate.d) Heterozygotes are dying quickly.

e) Homozygotes are becoming sterile.

Question 8

• During a heterozygote advantage you will have…?

a) Homozygotes dying in large amounts.b) Heterozygotes having better fitness.c) Homozygous individuals not being able to mate.d) Heterozygotes are dying quickly.

e) Homozygotes are becoming sterile.

Question 9

• When frequency-dependent selection is occurring, what is happening?

a) The amount of a certain allele occurring is low in homozygotes

b) Heterozygotes are dying at an alarming ratec) Fitness of a phenotype is declining as it becomes too

populatedd) Heterozygotes are dyinge) Homozygotes are dying

Question 9

• When frequency-dependent selection is occurring, what is happening?

a) The amount of a certain allele occurring is low in homozygotes

b) Heterozygotes are dying at an alarming ratec) Fitness of a phenotype is declining as it becomes too

populatedd) Heterozygotes are dyinge) Homozygotes are dying

Question 10

• What is one reason Natural Selection cannot fashion a perfect organism?

a) Adaptations are not compromisesb) Selection cannot act on existing variationsc) Chance, natural selection, and the environment interactd) Evolution is not limited by historical constraints.e) Chance, natural selection, and the enviroment do not

interact

Question 10

• What is one reason Natural Selection cannot fashion a perfect organism?

a) Adaptations are not compromisesb) Selection cannot act on existing variationsc) Chance, natural selection, and the environment interactd) Evolution is not limited by historical constraints.e) Chance, natural selection, and the enviroment do not

interact

Thanks for reading!!!!!!!!!!!!

CH. 24

The Origin Of Species

Key Terms• Speciation: process which one species splits into 2+

species• Microevolution: changes over time in allele frequencies

within a population over generations (genotypic cluster)• Macroevolution: broad pattern of evolution over a long

time span• Biological species concept: definition of species as a

population or group of populations whose numbers have potential to interbreed in nature and produce viable fertile offspring but not with members of other groups

• Species: group of populations whose members have potential to interbreed in nature and produce viable offspring

Key Terms (cont.)

• Reproductive Isolation: existence of biological factors that impede members of 2 species from producing viable offspring

• Hybrids: offspring that result from inter-specific mating

• Prezygotic barriers: impedes mating between species or blocks fertilization from occurring if inter-specific mating is attempted

• Postzygotic barriers: contribute to reproductive isolation after hybrid zygote formed

Key Terms (cont.)• Morphological species concept: characterizes species by body

shape and other structural features• Ecological species concept: views species in terms of its

ecological niche (the sum of how members of the species interact with the non-living and living parts of their environment)

• Phylogenetic species concept: species as smallest group of individuals share common ancestry, forming one branch (monophyletic) on the tree of life

• Allopatric speciation: gene flow interrupted when population divided into geographically isolated subpopulations

• Sympatric speciation: occurs in populations that live in the same geographic area

• Polyploidy: species originated from accident during cell division resulting in extra sets of chromosomes

Key Terms (cont.)

• Autopolyploid: individual that has 2+ chromosome sets derived from single species

• Allopolyploid: fertile individual has 2+ chromosome sets as a result of 2 different species interbreeding and combining chromosomes

• Hybrid zone: region which members of different species meet and mate, producing at least some offspring of mixed ancestry

• Reinforcement: natural selection strengthens prezygotic barriers to reproduction, thus reducing chances of hybrid formation

• Punctuated equilibria: long periods of apparent stasis in which species undergo little or no morphological change interrupted by relatively brief periods of sudden change

Key Ideas• Know the biological species concept and that it

emphasizes reproductive isolation through the 2 barriers that separate gene pools

• Limitations of the biological species concept: – Cannot be applied to fossils or asexual reproductive

organisms (prokaryotes)– Designated by the absence of gene flow

• Allopatric speciation can occur when 2 populations of 1 species become separated– Meanwhile, one or both may undergo evolutionary change,

resulting in the establishment of the 2 reproductive barriers• Sympatric speciation can overlap with the parent species

in the same geographic location– Can result from habitat shifts and sexual selection

Key Ideas (cont.)

• The difference between allopatric and sympatric speciation: – Sympatric – same geographic location– Allopatric – geographically separated

• Many groups of organisms form hybrid zones so the members of different species can mate to produce mixed-ancestry offspring

• Many hybrid zones have limited # of hybrid offspring that continue to be produced over time– In some hybrid zones, reinforcement strengthens prezygotic

reproductive barriers which decreases formation of unfit hybrid zones

– Other hybrid zones’ reproductive barriers may weaken over time, resulting in fusion of species’ gene pools

Key Ideas (cont.)• Prezygotic barriers: same common ancestor but cannot

produce offspring• Postzygotic barriers: offspring of parent species is

infertile • New species can form rapidly once divergence begins

– Time interval between speciation events varies from one thousand to tens of millions of years

• New developments have enabled researchers to identify specific genes – Results show speciation can be driven by few or many genes

• Due to repeated events, small differences in organisms can accumulate, leading to formation of new groups of organisms

1. Which species concept(s) could you apply to both sexual and asexual species?

a. Biological & Phylogeneticb. Morphologicalc. Phylogenetic & Ecologicald. A and Be. B and C

1. Which species concept(s) could you apply to both sexual and asexual species?

a. Biological & Phylogeneticb. Morphologicalc. Phylogenetic & Ecologicald. A and Be. B and C

2. Which type of speciation is more common?a. Sympatricb. Parapatricc. Allopatricd. Peripatric

2. Which type of speciation is more common?a. Sympatricb. Parapatricc. Allopatricd. Peripatric

3. Where is allopatric speciation more likely to occur?

a. Mainland islandb. Arctic environmentc. Isolated islandd. Freeman Lake

3. Where is allopatric speciation more likely to occur?

a. Mainland islandb. Arctic environmentc. Isolated islandd. Freeman Lake

4. Which of the following is an example of a postzygotic barrier?

a. Mating season of the Spotted skunksb. Offspring of a donkey and a horsec. Morphological differences in a snaild. Mating behaviors of the Blue-footed boobies

4. Which of the following is an example of a postzygotic barrier?

a. Mating season of the Spotted skunksb. Offspring of a donkey and a horsec. Morphological differences in a snaild. Mating behaviors of the Blue-footed boobies

5. Which form of polyploidy occurs when two different species interbreed and produce hybrid offspring?

a. Autopolyploidb. Allopolyploidc. Altopolyploidd. Accupolyploid

5. Which form of polyploidy occurs when two different species interbreed and produce hybrid offspring?

a. Autopolyploidb. Allopolyploidc. Altopolyploidd. Accupolyploid

6. The picture below is an example of which species concept?a. Biologicalb. Phylogeneticc. Ecologicald. Morphological

6. The picture below is an example of which species concept?a. Biologicalb. Phylogeneticc. Ecologicald. Morphological

7. The largest unit within which gene flow can readily occur is?

a. populationb. genusc. speciesd. phylume. hybrid

7. The largest unit within which gene flow can readily occur is?

a. populationb. genusc. speciesd. phylume. hybrid

8. According to the punctuated equilibria model,a. natural selection is unimportant as a

mechanism of evolutionb. given enough time, most existing species

will branch gradually into new species c. most new species accumulate their unique

feature relatively rapidly as they come into existenced. most evolution occurs in sympatric

populations

8. According to the punctuated equilibria model,a. natural selection is unimportant as a

mechanism of evolutionb. given enough time, most existing species

will branch gradually into new species c. most new species accumulate their unique

feature relatively rapidly as they come into existence

d. most evolution occurs in sympatric populations

9. What is/are limitations to the biological species concept?

a. Absence of gene flowb. Emphasizes concept of natural selectionc. Number of species is limitedd. A and Be. A and C

9. What is/are limitations to the biological species concept?

a. Absence of gene flowb. Emphasizes concept of natural selectionc. Number of species is limitedd. A and Be. A and C

10. Which long-term outcome of hybrid zones is a weakening of the reproductive barriers?

a. fusionb. stabilityc. reinforcementd. differentiation

10. Which long-term outcome of hybrid zones is a weakening of the reproductive barriers?

a. fusionb. stabilityc. reinforcementd. differentiation

CH. 25

The History of Life On Earth

Key Terms

• Macroevolution: broad pattern of evolution over large time scales

• Protobionts: collections of abiotically produced molecules surrounded by a membrane-like structure

• Ribozyme: RNA molecule that functions as enzyme, catalyzing reactions during RNA splicing

• Radiometric dating: dating of fossils based on decay of radioactive isotopes

• Half-life: time required for 50% of parent isotope to decay

Key Terms (cont.)

• Geologic Record: division of Earth’s history into time periods separated in 3 eons- Archaean, Proterozoic, Phanerozoic

• Stromatolites: layered rocks that form when certain prokaryotes bind thin films of sediment together

• Endosymbiosis: posits that mitochondria and plastids were formerly small prokaryotes that began living in larger cells

• Endosymbiont: cell that lives within another cell, host cell• Serial Endosymbiosis: model showing mitochondria

evolved before plastids through sequence of endosymbiotic events

Key Terms (cont.)

• Cambrian explosion: large, hard-bodied animals with most of major body plans known today appeared in the fossil record; 535-525 million years ago

• Continental drift: slow movement of continental plates across Earth’s surface

• Pangaea: plate movements that brought Earth’s landmasses together to form a super continent 250 million years ago

• Adaptive radiation: periods of evolutionary change in which groups of organisms form many new species whose adaptations allow to fill different ecological roles in communities

Key Terms (cont.)

• Heterochrony: evolutionary change in rate or timing of developmental events

• Paedomorphosis: retention in adult organisms of juvenile features of evolutionary ancestors

• Homeotic genes: master regulatory genes that determine location and arrangement of basic features will develop

• “Hox” genes: provide positional information in animal embryo

• Exaptations: structures that evolve in 1 context but become co-opted for another function

Key Ideas

• Lab experiments stimulating a reducing atmosphere produced organic molecules from inorganic precursors– Amino acids are found in meteorites and polymerize when

added to hot sand, clay, or rock• Organic compounds can spontaneously form in labs into

protobionts, membrane-bounded droplets with some properties of cells

• Early protobionts with RNA capable of guiding polypeptide synthesis and self-replication would’ve been more effective for using resources and increased natural selection #

Key Ideas (cont.)

• Fossil record documents rise and fall of different groups of organisms over time– Shows how new groups of organisms arise through gradual

modification of preexisting organisms– Sedimentary strata reveal relative ages of fossils; absolute

ages estimated by radiometric dating and others• Key events in life’s history are: origins of single and multi-

celled organisms and colonization of land• Continental drift alters physical geography and climate of

Earth– Can lead to extinctions of organisms or burst of speciation

Key Ideas (cont.)• 5 mass extinctions have altered history of life in evolutionary

history– Some possibly caused by changes in continent position, volcanic

activity, or meteorite/comet impact• Large increases in life diversity resulted from adaptive radiations

from mass extinctions– Also occurred in organism groups that had big evolutionary innovations

or colonized new regions with little competition• Developmental genes affect morphological differences within

species by influencing the rate, timing, spatial patterns of change as develops– Evolution of new morphological forms caused by nucleotide sequence

changes or developmental gene regulation

Key Ideas (cont.)

• Novel and complex biological structures can evolve through series of incremental modifications that benefits the organism

• Evolutionary trends caused by factors like natural selection in changing environment or species selection– Result from interactions between organisms and

current environments

1. A swim bladder is a gas-filled sac that helps fish maintain buoyancy. The evolution of the swim bladder from lungs of an ancestral fish is an example of

a. evolutionary trendb. paedomorphosisc. changes in Hox gene expressiond. adaptive radiatione. exaptation

1. A swim bladder is a gas-filled sac that helps fish maintain buoyancy. The evolution of the swim bladder from lungs of an ancestral fish is an example of

a. evolutionary trendb. paedomorphosisc. changes in Hox gene expressiond. adaptive radiatione. exaptation

2. All of the following promote adaptive radiation EXCEPT:

a. diversification of another group of organisms

b. migration to new locations where few competitor species exist

c. mass extinctionsd. continental drifte. major evolutionary innovations

2. All of the following promote adaptive radiation EXCEPT:

a. diversification of another group of organisms

b. migration to new locations where few competitor species exist

c. mass extinctionsd. continental drifte. major evolutionary innovations

3. Fossilized stromatolitesa. all date from 2.7 billion years agob. formed around deep-sea ventsc. resembles structures formed by

bacterial communities that are found today in some warm, shallow, salty bays

d. provide evidence that plants moved onto land in the company of fungi around 500 million years ago

3. Fossilized stromatolitesa. all date from 2.7 billion years agob. formed around deep-sea ventsc. resembles structures formed by

bacterial communities that are found today in some warm, shallow, salty bays

d. provide evidence that plants moved onto land in the company of fungi around 500 million years ago

4. All of the following are possible reasons that mass extinctions are caused EXCEPT:

a. continent positionb. volcanic activity c. meteorite/comet impactd. radiation

4. All of the following are possible reasons that mass extinctions are caused EXCEPT:

a. continent positionb. volcanic activity c. meteorite/comet impactd. radiation

5. Which of the following can lead to the extinction of organisms?

a. Cambrian explosionb. continental driftc. heterochronyd. paedomorphosis

5. Which of the following can lead to the extinction of organisms?

a. Cambrian explosionb. continental driftc. heterochronyd. paedomorphosis

6. For what is radiometric dating used?a. relative age dating of fossilsb. gene regulationc. estimating the absolute age of fossilsd. abiotic synthesis

6. For what is radiometric dating used?a. relative age dating of fossilsb. gene regulationc. estimating the absolute age of fossilsd. abiotic synthesis

7. What is the main function of ribozymes?a. catalyze reactions during RNA splicingb. photosynthesisc. supporting ancestral prokaryotesd. involved in nucleotide sequences

7. What is the main function of ribozymes?a. catalyze reactions during RNA splicingb. photosynthesisc. supporting ancestral prokaryotesd. involved in nucleotide sequences

8. Large increases in life diversity resulted from:a. Cambrian explosionb. adaptive radiations from mass

extinctionsc. heterochronyd. ancestral prokaryotes

8. Large increases in life diversity resulted from:a. Cambrian explosionb. adaptive radiations from mass

extinctionsc. heterochronyd. ancestral prokaryotes

9. Which of the following were found in meteorites?

a. ancestral prokaryotesb. ribozymesc. amino acidsd. mitochondria

9. Which of the following were found in meteorites?

a. ancestral prokaryotesb. ribozymesc. amino acidsd. mitochondria

10. Which phenomenon 535-525 million years ago introduced new types of animals?

a. Neutral theoryb. paedomorphosisc. Archaean explosiond. Cambrian explosion

10. Which phenomenon 535-525 million years ago introduced new types of animals?

a. Neutral theoryb. paedomorphosisc. Archaean explosiond. Cambrian explosion

Chapter 26of Evolution

Tim Whitehouse

10 most importants…

26.1 Tree of Life, Evolutionary RelationshipsPhylogeny- the evolutionary history of a species or group of species.Systematics- a discipline focused on classifying organisms and determining their evolutionary relationships.

Phylogeny based on DNA data shows humans are more closely related to fungi then either is to plant.Taxonomy- how organisms are named and classified.Binomial Nomenclature- the two part format of the scientific name.

The first part of a Binomial, is the Genus a species belongs to. The second part is the specific epithet, unique to its species.

26.1 Tree of Life, Evolutionary Relationships In the Linnaean System, Hierarchical Classification goes from least specific to most specific.

Domain>Kingdom>Phylum>Class>Order>Family>Genus>Species.

Taxon- the named taxonomic unit at any level of the hierarchy.Phylogenic Trees- a branching diagram showing the evolutionary history of a group of organisms.PhyloCode- only naming groups that include a common ancestor and all its descendants.Branch Points- represent divergence of two evolutionary lineages from a common ancestor.

A

BC

DEF

SisterTaxa

2

1

3

4

Branch point, AKA a node.

This branch point represents most recent ancestor of taxa A-F

A polytomy- an unresolved pattern of divergence

26.1 Tree of Life, Evolutionary RelationshipsWhat is the order of the Linnaean Hierarchy Classification System from biggest to smallest?

a)Kingdom, Domain, Phylum, Class, Order, Family, Genus, Speciesb)Domain, Kingdom, Phylum, Class, Order, Family, Genus, Speciesc)Species, Genus, Family, Order, Class, Phylum, Kingdom, Domain

#1

26.1 Tree of Life, Evolutionary RelationshipsWhat is the order of the Linnaean Hierarchy Classification System from biggest to smallest?

a)Kingdom, Domain, Phylum, Class, Order, Family, Genus, Speciesb)Domain, Kingdom, Phylum, Class, Order, Family, Genus, Speciesc)Species, Genus, Family, Order, Class, Phylum, Kingdom, Domain

#1

26.1 Tree of Life, Evolutionary RelationshipsWhich of the trees shown below depicts a different evolutionary history for taxa A-D than the other two?

A

BCD

a)

BDCA

b)

DCBA

c)

#2

26.1 Tree of Life, Evolutionary RelationshipsWhich of the trees shown below depicts a different evolutionary history for taxa A-D than the other two?

A

BCD

a)

BDCA

b)

DCBA

c)

#2

26.2 Morphological and Molecular DataAnalogy- similarities in two species due to Convergent evolutionHomology- similarities in two species due to shared ancestry. Homoplasies- analogous (similar) structures that arose independently.

Molecular Systematics- the discipline that uses DNA and other molecular data to determine evolutionary relationships.

A C G G A T A G T C C A C T A G G C A C T A

T C A C C G A C A G G T C T T T G A C T A G

Molecular homoplasy, these two DNA sequences coincidently share 25% of their bases.

26.2 Morphological and Molecular Data

Suppose that species 1 and species 2 have similar appearances but very different gene sequences, and that species 2 and species 3 have very different appearances but similar gene sequences. Which pair of species is more likely to be closely related: 1 and 2, or 2 and 3? Explain.

#3

#326.2 Morphological and Molecular Data

Suppose that species 1 and species 2 have similar appearances but very different gene sequences, and that species 2 and species 3 have very different appearances but similar gene sequences. Which pair of species is more likely to be closely related: 1 and 2, or 2 and 3? Explain.

2 and 3 are more closely related because genes can cause huge changes in appearance, even with small gene differences.

26.3 More Polygenic TreesCladistics- systematics using common ancestry to organize and classify organisms.Clades- groups which includes an ancestor and all of its descendants.

AB

C

D

EF

G

AB

C

D

EF

G

AB

C

D

EF

G

1

2

3

4

1

Monophyletic- an ancestor and all its descendants.

2Paraphyletic- an ancestor and most of its descendants.

3 4

Polyphyletic- taxa with different ancestors.

26.3 More Polygenic TreesShared Ancestrial Character- a character that originated in an ancestor of the taxon.Shared Derived Character- an evolutionary novelty unique to a particular clade.Outgroup- a species or group of species from an evolutionary lineage that is known to have diverged before the lineage that includes the species in question.Ingroup- the species or group of species in question, being studied.

Note: on a phylogenic tree, branch lengths can be proportional to relative amounts of genetic change or to relative amounts of time passed.

Maximum Parsimony- the idea that the one should first investigate the simplest explanations that are consistent with the facts. Simplest is best. (A.K.A the “Occam’s Razor”)Maximum Likelihood- given certain rules about DNA changes over time, a tree can be found that reflects the most likely sequence of evolutionary events.

0 40%30%

40%

0

0

Human Mushroom Tulip

Human

Mushroom

Tulip

a) Percentage differences between sequences

26.3 More Polygenic TreesPhylogenetic Bracketing- using parsimony to predict that features shared by two groups of closely related organisms are present in their common ancestor and all of its descendants, unless independent data indicates otherwise.

To distinguish a particular clade of mammals within the larger clade that corresponds to class Mammalia, would hair be a useful character? Why or why not?

#4

a ) Yes, to try to split up the class Mammalia into smaller groups or clades, using the character of hair would not help. All mammals have hair.

b) no.

26.3 More Polygenic TreesPhylogenetic Bracketing- using parsimony to predict that features shared by two groups of closely related organisms are present in their common ancestor and all of its descendants, unless independent data indicates otherwise.

To distinguish a particular clade of mammals within the larger clade that corresponds to class Mammalia, would hair be a useful character? Why or why not?

a ) Yes, to try to split up the class Mammalia into smaller groups or clades, using the character of hair would not help. All mammals have hair.

#4

b) no.

26.4 More Evolutionary History, GenesDifferent genes evolve at different rates, even in the same evolutionary

lineage.

Orthologous Genes- homologous genes that are found in different species because of speciation.Paralogous Genes- caused by gene duplication, so they are found in more than one copy in the same genome.

Ancestral gene

Speciation with divergence of gene

Species A Species B

a) Orthologous genes

Species A

Gene duplication and divergence

Species A after many generations

b) Paralogous genes

26.4 More Evolutionary History, GenesWhich of the following is the figure displaying?

a) Paralogous genesb) Orthologous genesc) Maximum Parsimony

Species A

Gene duplication and divergence

Species A after many generations#5

26.4 More Evolutionary History, GenesWhich of the following is the figure displaying?

a) Paralogous genesb) Orthologous genesc) Maximum Parsimony

Species A

Gene duplication and divergence

Species A after many generations#5

26.5 Evolutionary Time, Molecular ClocksMolecular clock- measures the absolute time of evolutionary change based on the observation that some genes and other regions of genomes appear to evolve at constant rates.Neutral Theory- states that much evolutionary change inn genes and proteins has no effect on fitness and therefore is not influenced by Darwinian Selection.

Note: Debate against the Neutral Theory and the Molecular Clock concept has been influenced by skepticism about how much natural selection effects evolutionary change.

26.5 Evolutionary Time, Molecular ClocksWhat is a Molecular Clock?

a) the thing that makes you wake up in the morning.b) a measuring tool for molecules.c) a concept for the absolute time of evolutionary change based on the observation that some genes and other regions of genomes appear to evolve at constant rates.

#6

26.5 Evolutionary Time, Molecular ClocksWhat is a Molecular Clock?

a) the thing that makes you wake up in the morning.b) a measuring tool for molecules.c) a concept for the absolute time of evolutionary change based on the observation that some genes and other regions of genomes appear to evolve at constant rates.

#6

26.6 Understanding the Tree of LifeToday, it is accepted that there are no longer just plants and animals. The

highest level of hierarchy classification is three Domains. ( Eukarya, Archaea, and Bacteria ) The stages scientist went through to come to these Domains were…

1st plant vs animal2nd Plantae, Fungi, Animalia, Monera, and Protista3rd The Domains- Bacteria, Eukarya, and Archaea

26.6 Understanding the Tree of Life

Common ancestor of all life

eukarya

archaea bacteria

Land plants

Animals

Fungi

26.6 Understanding the Tree of LifeSome scientists say the tree of life is more like the ring of life. They say this due to

the idea of Horizontal Gene Transfer- a process in which genes are transferred from one genome to another through mechanisms such as exchange of transposable elements and plasmids, viral infection, and perhaps fusions of organisms.

Eukarya

ArchaeaBacteria

26.6 Understanding the Tree of LifeWhat are the three Domains?

a) Bacteria, Plants, and Animalsb) Eukaryotes, Prokaryotes, and Bacteriac) Archaea, Eukarya, and Bacteria

#7

What are the three Domains?

a) Bacteria, Plants, and Animalsb) Eukaryotes, Prokaryotes, and Bacteriac) Archaea, Eukarya, and Bacteria

26.6 Understanding the Tree of Life

#7

What does Maximum Parsimony mean?

a) the simplest answer is the bestb) the most complex answer is the right onec) the most possible amount of “Parsi” a

species can have

#8

What does Maximum Parsimony mean?

a) the simplest answer is the bestb) the most complex answer is the right onec) the most possible amount of “Parsi” a

species can have

#8

If the species under study were A-C, then what is the term for species D?

A

BCD

a) Paralogousb) the Ingroupc) the Outgroup

#9

If the species under study were A-C, then what is the term for species D?

A

BCD

a) Paralogousb) the Ingroupc) the Outgroup

#9

#10

If DNA and other molecular data were used to compare evolutionary relationships, then the use of classifying could be defined as…

a) Cladisticsb) Molecular Systematicsc) PhyloCode

#10

If DNA and other molecular data were used to compare evolutionary relationships, then the use of classifying could be defined as…

a) Cladisticsb) Molecular Systematicsc) PhyloCode

Chapter 29

Plant Diversity I: How Plants

Colonized Land

Key terms:

1. Sporopollenin - Layer of durable polymer that prevents exposed zygotes from drying out.

2. Phragmoplast - Group of microtubules that form between the daughter nuclei of a dividing cell.

3. Gametophyte - Haploid that is named for its production by mitosis of haploid gametes eggs and sperm that fuse, and form diploid zygotes.

4. Sportophyte - Multicellular diploid produced during mitosis division of the zygote.

5. Haploid spores - Produced during Meiosis in a mature sporophyte.

Key terms Contd. :

6. Sporangia - Multicellular organs in a sporophyte.7. Sporocytes - Diploid cells or spore mother cells, that

undergo meiosis and generate the haploid spores.8. Gametangia - Gametes within multicellular organs.9. Archegonia – The female gametangia.10. Vascular tissue - Cells that are joined into tubes

that transport water and nutrients throughout the plant body.

Top Ten List

• 1. Algae and land plants have many of the same characteristics:

Plants have multicellular, eukaryotic, photosynthetic autotrophs, as do brown, red, and certain green algae. Plants have cell walls made of cellulose as do green algae.

Top Ten List contd. 2. Although Land plants and algae are similar there are four major

differences: The first is alternation of Generations, which is a life cycle in which there is both

a multicellular diploid form, the sporophyte, and a multicellular haploid form, the gametophyte; characteristics of plants and some algae.

The second is plant spores produce spores that have multicellular sporangia unlike algae spores that are flagellated, and lack sporopollenin.

The third way that land plants and algae are different is by that land plants produce gametes within multicellular organs called gametangia unlike alga.

The fourth and final way that land plants and algae are different is by that plants roots and shoots can elongate, increasing exposure to environmental resources. This growth in length is sustained throughout the plant’s life by the activity of apical meristems, that are localized regions of cell division at the tips of shoots and roots.

Top Ten List contd.

• 3. The origin of PlantsThe origin of plants is still being debated but the

oldest fossil evidence is fossil spores from the Ordovician period. These spores were released in a bundle with two to four spores in each fused together unlike spores today that are released by themselves.

Top Ten List contd.

• 4. Bryophyte Gametophytes Gametophytes are the dominant stage of the life

cycle. They are longer living than the sporophytes and are typically most visible. They generally form ground hugging carpets, for example the gametophytes that make up a carpet of moss.

Top Ten List contd.

• 5. Bryophyte Sporophytes Sporophytes grow out of archegonia and are

attached to and dependent on the haploid gametophytes for nourishment. They are smaller and much more simplier than vascular plan sporophytes.

Top Ten List contd.

• 6. Origin of Vascular PlantsFossils of the forerunners of today’s vascular

plants date back to about 420 million years and show that these small plants had independent, branching sporophytes. The ancestor of the vascular plant did lack significant traits such as a life cycle with dominant sporophytes and lignified vascular tissue.

Top Ten List contd.

• 7. Evolution of Roots Lignified vascular tissue also provides benefits

below ground. Roots have evolved in almost all vascular plants. Roots are organs that absorb water and nutrients from soil. Roots also anchor vascular plants, hence allowing the shoot system to grow taller.

Top Ten List contd.

8. Evolution of LeavesLeaves increase the surface area of the plant

body and serve as the primary photosynthetic organ of vascular plants. Leaves can be classified as either microphylls or megaphylls. Microphylls originated from sporangia located on the side of the stem. Megaphylls evolved from a series of branches lying close together on a stem.

Top Ten List contd.

• 9. Classification of Seedless Vascular PlantsSeedless vascular plants include phylum

Lycophyta (mosses) and phylum Pterophyta (ferns, horsetails, and whisk ferns). Ancient lycophytes included both small herbaceous plants and large treelike plants.

Top Ten List contd.

10. The Significance of Seedless Vascular PlantsSeedless vascular plants dominated the earliest

forests. Their growth may have helped to produce the major global cooling that characterized the end of the Carboniferous period.

Extra info.

• An example of a seedless vascular plant is a spike moss.

• Charophyte is a land plant that produces flagellated sperm and has a sporophyte-dominated life cycle.

• Liverworts is one of the bryophytes phyla .• Carbonforous is the period that seedless

vascular plants help to produce the major global cooling that ended this period.

Extra Info.

• The range of height for a moss is from 1mm up to 2m.

• the fossil spores that were found in the 1970s were from the Ordovician period.

• Leaves increase the surface area of the plant body and serve as the primary photosynthetic organ of vascular plants.

• Roots absorb water and nutrients from the soil.• The decaying remnants of the first forests became

coal.

Diagram ( lifecycle of moss)

Diagram (lifecycle of moss)

• The diagram lifecycle of moss shows the moss from the spore developing into threadlike protonemata to the moss full grown and then finally the moss releasing its seeds to start the process all over again.

Diagram (lifecycle of a fern)

Diagram (lifecycle of a fern)

• The diagram shows the fern from when the spores are first released to the plant slowly growing into the adult fern to that adult fern producing spores and restarting the life cycle.

Multiple Choice

• 1. What is one example of a seedless vascular plant?

a. Red roses b. spike mosses c. Tiger tulips d. Yellow Daffodil e. monkey grass

Answers

• 1. What is one example of a seedless vascular plant?

a. Red roses b. spike mosses c. Tiger tulips d. Yellow Daffodil e. monkey grass

Multiple Choice

• 2. Which of the following is a land plant that produces flagellated sperm and has a sporophyte-dominated life cycle?

a. Moss b. charophyte c. hornwort d. fern e. fescue

Answers

• 2. Which of the following is a land plant that produces flagellated sperm and has a sporophyte-dominated life cycle?

a. Moss b. charophyte c. hornwort d. fern e. fescue

Multiple Choice

• 3. Identify one of the bryophytes phyla from the following choices:

a. Sporophytesb. Sphagnum c. liverwortsd. Hordophytes e. carboniferous

Answers

• 3. Identify one of the bryophytes phyla from the following choices:

a. Sporophytesb. Sphagnum c. liverwortsd. Hordophytes e. carboniferous

Multiple Choice

4. In what period did Seedless Vascular Plants help to produce the major global cooling that ended this period?

a. Carboniferousb. Habroniferous c. Otdovician d. Crestacious e. sphagnum

Answers

4. In what period did Seedless Vascular Plants help to produce the major global cooling that ended this period?

a. Carboniferousb. Habroniferous c. Otdovician d. Crestacious e. sphagnum

Multiple Choice

• 5. What is the range of height for a moss?a. 1mm up to 2m b. 3mm up to 7m c. 2mm up to 5 mm d. 8 mm up to 12 mm. e. .5mm up to 3mm

Answers

• 5. What is the range of height for a moss?a. 1mm up to 2m b. 3mm up to 7m c. 2mm up to 5 mm d. 8 mm up to 12 mm. e. .5mm up to 3mm

Multiple Choice

6. What is one name for green algae?a. Charophytes b. flarophytes c. granophytes d. Ranophytes e. bryophytes

Answers

6. What is one name for green algae?a. Charophytes b. flarophytes c. granophytes d. Ranophytes e. bryophytes

Multiple Choice

7. In what time period is the fossil spores from that was found in the 1970s ?

a. Craustacusb. Ordovician c. Neoclassical d. Gardovician e. Romantic

Answers

7. In what time period is the fossil spores from that was found in the 1970s ?

a. Craustacusb. Ordovician c. Neoclassical d. Gardovician e. Romantic

Multiple Choice

• 8. Which of the following increase the surface area of the plant body and serve as the primary photosynthetic organ of vascular plants ?

a. Strobili b. Stemc. roots d. Leavese. petals

Answers

• 8. Which of the following increase the surface area of the plant body and serve as the primary photosynthetic organ of vascular plants ?

a. Strobili b. Stemc. roots d. Leavese. petals

Multiple Choice

9. What is an organ that absorbs water and nutrients from the soil?

a. Leavesb. roots c. homosporous d. moss e. petals

Answers

9. What is an organ that absorbs water and nutrients from the soil?

a. Leavesb. roots c. homosporous d. moss e. petals

Multiple Choice

10.What did the decaying remnants of the first forests become?

a. Coalb. lava c. trees d. Animalse. rock

Answers

10.What did the decaying remnants of the first forests become?

a. Coalb. lava c. trees d. Animalse. rock

Chapter 30

Plant Diversity II:The Evolution of Seed Plants

Key Terms

• 1. Seed – consists of an embryo and its food supply, surrounded by a protective coat.

• 2. Integument – Is a layer of sporophyte tissue that envelops and protects the megasporangium.

• 3. Pollination – The transfer of pollen to the part of a seed plant that contains the ovules.

• 4. Progymonsperms – A seedless vascular plant.• 5. Conifers - Cone-bearing gymnosperms found in forest in

the northern latitudes. • 6. Flower – Is an angiosperm structure specialized for

sexual reproduction.

Key Terms

• 7. Sepals – Usually green and enclose the flower before it opens. Located at the base of the flower.

• 8. Petals- Interior of sepals. Brightly colored in most flowers and aid in attracting pollinators.

• 9. Stamens- Produce microspores that develop into pollen grains containing male gametophytes.

• 10. Fruit- Typically consists of a mature ovary, although It can include other flower parts as well.

Top Ten List

• 1. Advantages of Reduced Gametophytes The evolutionary trend of gametophyte reduction continued further

in the vascular plant lineage that led to seed plants. The miniaturization in gametophytes allowed for an important evolutionary innovation in seed plants: their tiny gametophytes can develop from spores retained within the sporangia of the parental sporophyte. This protects the delicate female gametophytes from environmental stresses. The moist reproductive tissues of the sporophyte shield the gametophytes from UV radiation and protect against drying out. This relationship enables dependent gametophytes to obtain nutrients from the sporophyte.

Top Ten List contd.

2. Evolutionary Advantage of SeedsIf sperm fertilizes an egg of a seed plant, the zygote grows

into a sporophyte embryo. Until the advent of seeds, the spore was the only protective stage in any plant life cycle. Although mosses and other seedless plants continue to be very successful today, seeds represent a major evolutionary innovation that contributed to the opening of new ways of life for seed plants. Seeds have an extra protective coating called seed coat that adds protection to the embryo and supplies stored food. This enables the seed to remain dormant for days, months, and even years.

Top Ten List contd.

3. Gymnosperm Evolution Gymnosperms appear early in the plant fossil

record and dominated Mesozoic terrestrial ecosystems. Living seed plants can be divided into two monophyletic groups: gymnosperms and angiosperms. The first seed bearing plants appeared from around 360 million years ago, more than 200 million years before the first angiosperm fossils.

Top Ten List contd.

4. The Life Cycle of a PineDominance of the sporophyte generation, the

development of seeds from fertilized ovules, and the role of pollen in transferring sperm to ovules are key features of a typical gymnosperm life cycle. From the time young pollen and ovulate cones appear on the pine tree, it takes almost three years for the male and female gametophytes to be produced and brought together and mature seeds to form from the fertilized ovules.

Top Ten List contd.

5. Characteristics of AngiospermsFlowers generally consist of four whorls of

modified leaves: sepals, petals, stamens, and carpels. Ovaries ripen into fruits, which often carry seeds by wind, water, or animals to new locations. All angiosperms are classified in a single phylum, anthophyta (flower)

Top Ten List contd.

6. Angiosperm Evolution An adaptive radiation of angiosperms occurred

during the Cretaceous period. Fossils, phylogenetic analyses, and developmental studies offer insights into the origin of flowers. It is still a mystery as to the origin of angiosperms and how they developed from earlier seed plants.

Top ten list contd.

• 7. Angiosperm Diversity Several groups of basal angiosperms have been

identified. Other major clades of angiosperms include monocots, magnoliids, and eudicots. Angiosperms have diversified from over 250,000 living species. Until the late 1990’s, flowering plants were divided into two groups (monocots and dicots). Now due to DNA studies, they are divided into major clades.

Top ten list contd.

8. Evolutionary Links Between Angiosperms and Animals

Pollination and other interactions between angiosperms and animals may have led to increased species diversity in both of these groups. Insects that move from flower to flower as well as herbivores eating plant’s roots, leaves, or seed can effect the evolution of terrestrial plants.

Top ten list contd.

9. Products from Seed Plants Most of our food comes from angiosperms. Today’s crops are the

products of a relatively recent burst of genetic change, resulting from artificial selection after humans began domesticating plants about 13,000 years ago. These plant variations can range from size differences to the bitter vs. sweet taste in domesticated foods versus those found growing in the wild. Humans have used the seed plants to create a sweeter less fatal almond to creating herbs and bark from trees for medicine.

Top Ten List contd.

10. Threats to Plant Diversity Although plants may be a renewable resource, plant diversity is not.

The exploding human population and its demand for space and resources are extinguishing plant species at an extremely rapid rate. The problem is very severe in the tropics where half the human population lives and where population growth is fastest. The most common cause is the slash and burn clearing for agricultural use in the tropical rain forest. As forest disappear, so do thousands of plant species. This will have a domino effect on the earth’s ecosystem and the number of species that will be lost due to inability to survive. Once a plant becomes extinct, it will not be able to return again.

Extra Info

• A flower is an angiosperm structure specialized for sexual reproduction found on a plant.

• A fruit consist of Mature ovary and may include other flower parts.

• A Several intriguing fossils of 125-million-year-old angiosperms was found in China in the late 1990s.

• Magnoliids consist of 8,000 different species.• One of the six crops that contribute to the 80% of

all the calories consumed by humans is rice.

Extra info

• One use of the compound morphine is as a pain reliever.

• One use of the compound quinine is as a malaria preventer.

• Two of the world’s most popular beverages comes from tea leaves and coffee beans.

• A little under 5,000 species have been studied as potential sources of medicines.

• 25% percent of prescription drugs contain one or more active ingredients extracted or derived from plants.

Diagram of a flower structure

Diagram • The idealized structure of a flower include

petals, sepal, ovule, ovary, style, stigma, anther and filament. Without all of these a flower would not be 100% complete these parts of the flower are all very vital to its survival.

Diagram (life cycle of an angiosperm)

Diagram (life cycle of an angiosperm)

• The diagram shows the angiosperms life cycle starting on the anther, where each microsporangium contains microsporophytes that divide by meiosis, producing microspores. To the final stage when a seed germinates, and the embryo develops into a mature sporophyte.

Multiple Choice

• 1. Which of the following is an angiosperm structure specialized for sexual reproduction found on a plant?

a. Flowerb. sepals c. petals d. stamens e. stem

Answers

• 1. Which of the following is an angiosperm structure specialized for sexual reproduction found on a plant?

a. Flowerb. sepals c. petals d. stamens e. stem

Multiple Choice

2. What does a fruit consist of ? a. Mature ovary and may include other flower

parts.b. The sepals and petals c. The stamen and the flowerd. seeds and meat e. juice

Answers

2. What does a fruit consist of ? a. Mature ovary and may include other flower

parts.b. The sepals and petals c. The stamen and the flowerd. Seeds and meat e. Juice

Multiple Choice

• 3. What was found in China in the late 1990s?a. A large 50 foot tall plantb. Several intriguing fossils of 125-million-year-

old angiosperms.c. The oldest tree living from 154 thousand

years ago.d. 500 new species of rice. e. New species of trees.

Answers

• 3. What was found in China in the late 1990s?a. A large 50 foot tall plantb. Several intriguing fossils of 125-million-

year-old angiosperms.c. The oldest tree living from 154 thousand

years ago.d. 500 new species of rice. e. New species of trees.

Multiple Choice

4. How many species do magnoliids consist of? a. 5,000 b. 200 c. 8,000 d. 900 e. 500

Answers

4. How many species do magnoliids consist of? a. 5,000 b. 200 c. 8,000 d. 900 e. 500

Multiple Choice

5. What is one use of the compound morphine?

a. heart medication b. pupil dilator in eye exam c. pain reliever d. cancer treatment e. diabetes

Answers

5. What is one use of the compound morphine?

a. heart medication b. pupil dilator in eye exam c. pain reliever d. cancer treatment e. diabetes

Multiple Choice

• 6. What is one use of the compound Quinine? a. Muscle relaxant b. pain reliever c. saltd. Malaria preventive e. antibiotic

Answers

• 6. What is one use of the compound Quinine? a. Muscle relaxant b. pain reliever c. saltd. Malaria preventive e. antibiotic

Multiple Choice

7. What is one of the six crops that contribute to the 80% of all the calories consumed by humans?

a. chocolate b. strawberries c. rice d. sugar cane e. cocoa

Answers

7. What is one of the six crops that contribute to the 80% of all the calories consumed by humans?

a. chocolate b. strawberries c. rice d. sugar cane e. cocoa

Multiple Choice

• 8. Two of the world’s most popular beverages come from what two plant leaves/beans?

a. Tea leaves/coffee beansb. oak leaves/ black eyed peas c. maple leaves/cocoa beans d. Dogwood leaves/ vanilla beans e. Sequoia leaves/ castor beans

Answers

• 8. Two of the world’s most popular beverages come from what two plant leaves/beans?

a. Tea leaves/coffee beansb. oak leaves/ black eyed peas c. maple leaves/cocoa beans d. Dogwood leaves/ vanilla beans e. Sequoia leaves/ castor beans

9. How many plant species have been studies as potential sources of medicines?

a. 3,000 species b. 1,000 species c. 5,000 species d. 500 species e. 800 species

Answers

9. How many plant species have been studies as potential sources of medicines?

a. 3,000 species b. 1,000 species c. 5,000 species d. 500 species e. 800 species

Multiple Choice

• 10. What percent of prescription drugs contain one or more active ingredients extracted or derived from plants ?

a. 10 % b. 8% c. 75% d. 25 % e. 95%

Answers

• 10. What percent of prescription drugs contain one or more active ingredients extracted or derived from plants ?

a. 10 % b. 8% c. 75% d. 25 % e. 95%

Free Response 1

3. Invasive species, such as red fire ants, introduced into an ecosystem often threaten native plants and animals.

(a) Describe THREE different factors that contribute to the success of invasive species in an ecosystem.

(b) Discuss THREE ways that an invasive species can affect its new ecosystem.

(c) The map indicates the spread of the red fire ant after its initial entrance into the United States at the port ofMobile, Alabama, in the 1930s. Discuss TWO environmental factors that might have determined the patternof fire ant invasion.

(d) Discuss TWO possible methods of eradicating or slowing the spread of these ants, including theenvironmental consequences of each method.

Free Response 2

4. Phylogeny reflects the evolutionary history of organisms.(a) Discuss TWO mechanisms of speciation that lead to the development of separate species from a commonancestor.(b) Explain THREE methods that have been used to investigate the phylogeny of organisms. Describe astrength or weakness of each method.(c) The two phylogenetic trees represent the relationship of whales to six other mammals. All of the organismsshown have a pulley-shaped astragalus bone in the ankle except for the whale.• For each tree, describe a monophyletic group, the closest relative to the whale, and the point at whichthe pulley astragalus was lost or gained.

• Based on the principle of parsimony (the simplest explanation is the best) and the genomic informationin the table shown, identify which tree is the best representation of the evolutionary relationship ofthese animals, and justify your answer.

Kevin Britt- chapters 22 & 23Brennan Ray- chapters 24 & 25Tim Whitehouse- chapter 26 and FRAJ Walters- chapters 29 & 30