Keystone Biology Review
Central York High School
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Topics
Cells and Cell Processes
Continuity and Unity of Life
• Explain the characteristics common to all organisms◦ Describe the characteristics of life shared by all prokaryotic
and eukaryotic organisms
• Describe relationships between structure and function at biological levels of organization◦ Compare cellular structures and their functions in
prokaryotic and eukaryotic cells
◦ Describe and interpret relationships between structure and
function at various levels of biological organization
Basic Biological Principles
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Prokaryotes: Unicellular organisms with no nucleus or membrane-bound organelles◦ Bacteria
Eukaryotes: Unicellular or multicellular organisms with a nucleus and membrane-bound organelles◦ Plants, Animals, Fungi and Protists
Basic Biological PrinciplesDescribe the characteristics of life shared by all prokaryotic and eukaryotic organisms
All living organisms:
DNA – universal genetic code
Growth and Development
Cells – basic unit of life
Metabolism – Chemical reactions in the body
(ex: photosynthesis and respiration)
Reproduce
Response
Evolve – as a species, change over time
Dr Green Can Make Really Rotten Eggs
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Basic Biological PrinciplesCompare cellular structures and their functions in prokaryotic and eukaryotic cells
Prokaryotes Eukaryotes
Size Small Animals – largePlants – Very large
Examples Bacteria (E. coli) Plants, Animals, Fungi, and Protists
DNA Yes – circular strand of DNA Yes – folded into chromosomes
Ribosomes Yes Yes
Cell Membrane ALWAYS! ALWAYS!
Cell Wall Usually(made of peptidoglycan)
Animals – NOPlants – Yes (cellulose)
Membrane – Bound Organelles None
Golgi apparatus, mitochondria, chloroplasts, Endoplasmic Reticulum,
LysosomesMAIN
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Basic Biological PrinciplesCompare cellular structures and their functions in prokaryotic and eukaryotic cells
Organelle FunctionNucleus Contains DNA, Controls CellRibosomes Makes first version of proteinsEndoplasmic Reticulum
Rough – Protein assemblySmooth – Lipid synthesis
Golgi apparatus Modifies, sorts and packages proteinsLysosomes Contain enzymes that break down materialsVacuoles Material storageMitochondria Site of cellular respirationChloroplasts Site of photosynthesis – plants only!Cytoskeleton Maintain cell shapeCytoplasm “Cell liquid” – everything in the cell except the nucleus
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Basic Biological PrinciplesCompare cellular structures and their functions in prokaryotic and eukaryotic cells
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Cell specialization:
Stem cells divide to
become specialized
cells, where some
genes are “turned off”
*This allows a single
celled zygote to
divide and become
every other cell type
Basic Biological PrinciplesDescribe and interpret relationships between structure and function at various levels of biological organization
censored
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• Describe how the unique properties of water support life on Earth
◦ Describe the unique properties of water and how these properties support
life on Earth
• Describe and interpret relationships between structure and functions
at various levels of biochemical organization (i.e., atoms, molecules,
and macromolecules)
◦ Explain how carbon is uniquely suited to form biological macromolecules
◦ Compare the structure and function of carbohydrates, lipids, proteins, and
nucleic acids in organisms
◦ Describe how biological macromolecules form from monomers
• Explain how enzymes regulate biochemical reactions within a cell
◦ Describe the role of an enzyme as a catalyst in regulating a specific
biochemical reaction
◦ Explain how factors such as pH, temperature, and concentration levels can
affect enzyme function
The Chemical Basis for Life
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The Chemical Basis for Life
Charact-eristic
Explanation How it supports life on Earth
Polarity Electrons pull more toward oxygen than hydrogen, so there is an overall negative charge near oxygen and positive near hydrogen
Polarity leads to cohesion, adhesion, and water’s property as a universal solvent
Cohesion Water molecules stick together Cause capillary action
Adhesion Water molecules attract to other molecules Cause capillary action
Capillary action Water molecules move up small vessels Ex: Trees use cap. act. to get water to tops
Density Solid water (ice) is less dense than liquid water Ex: Polar bears! And lakes don’t freeze solid
High specific heat
It takes a lot of heat to increase the temp. of water; good at resisting temperature change
Ex: Oceans and lakes regulate Earth temps; sweating removes heat
Universal Solvent
Water is polar and can dissolve other polar substances Water is the main solvent for most chemical reactions in living organisms
Describe the unique properties of water and how these properties support life on Earth (e.g., freezing point, high specific heat, cohesion)
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The Chemical Basis for Life
• Carbon has four valence electrons
• Carbon can:◦ Bond with itself
◦ Bond with other molecules
◦ Form up to four covalent bonds
◦ Form single, double, or triple
bonds
• Carbon is the basis for living organisms due to this ability
Explain how carbon is uniquely suited to form biological macromolecules
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The Chemical Basis for LifeCompare the structure and function of carbohydrates, lipids, proteins, and nucleic acids in organisms
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Fats, Oils, Waxes
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The Chemical Basis for Life
• Carbohydrates – ◦ Carbon, hydrogen and oxygen in 1:2:1 ratio◦ Quick energy for the cell
• Lipids – ◦ Mostly carbon and hydrogen with some oxygen◦ Insoluble in water◦ Fats, oils, waxes and steroids
• Proteins – ◦ CHON(s) : Carbon, hydrogen, oxygen, nitrogen, sometimes sulfur◦ Structure, hormones, enzymes, transport
• Nucleic Acids – ◦ Nucleotides: 5 carbon sugar, phosphate (PO4) and nitrogen bases◦ Genetic information
Compare the structure and function of carbohydrates, lipids, proteins, and nucleic acids in organisms
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The Chemical Basis for Life
• Condensation:
◦ AKA “dehydration synthesis”
◦ Bond monomers together to
form polymers
◦ Removal of water
• Hydrolysis
◦ “water breaking”
◦ Addition of water molecule to
separate polymers into
smaller units
Describe how biological macromolecules form from monomers
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The Chemical Basis for Life
• Enzymes are biological catalysts which reduce the activation energy, or energy necessary to start a reaction.
• This allows chemical reactions to happen in the body that would otherwise not be possible.
Describe the role of an enzyme as a catalyst in regulating a specific biochemical reaction
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The Chemical Basis for Life
• Every enzymes operates best under optimal pH and temperature◦ If conditions are outside of optimal, then overall function will decrease◦ Each enzyme has a different optimal pH and temp; enzymes in the
stomach work best with acidic pH whereas enzymes in bacteria that live in hot springs would have optimal pH in higher temperatures
• Enzymes are proteins – when proteins are too hot or the pH is too acidic or basic, they can become denatured.
• Once a protein is denatured, it willnot work again
• Enzymes end in -ase
Explain how factors such as pH, temperature, and concentration levels can affect enzyme function
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• Identify and describe the cell structures involved in processing energy.◦ Describe the fundamental roles of plastids (e.g.,
chloroplasts) and mitochondria in energy transformation
• Identify and describe how organisms obtain and transform energy for their life processes◦ Compare the basic transformation of energy during
photosynthesis and cellular respiration
◦ Describe the role of ATP in biochemical reactions
Bioenergetics
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Bioenergetics
Chloroplasts
• Only in plants and photosynthetic algae
• Photosynthesis
Describe the fundamental roles of plastids (e.g., chloroplasts) and mitochondria in energy transformation
Mitochondria
• In all eukaryotes
• Cellular respiration
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Bioenergetics
Photosynthesis• Light dependent reactions
◦ Light is used to break water◦ Light energy transferred to
chemical energy in ATP and NADPH
◦ Oxygen released as waste
• Light Independent reactions◦ “Carbon fixation”◦ ATP and NADH are used to
create covalent bonds between carbons (from CO2)
◦ Sugars are produced as long term storage for energy
Compare the basic transformation of energy during photosynthesis and cellular respiration
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Bioenergetics
Cellular Respiration
• Glycolysis◦ Breaks glucose into 2 pyruvate
• Krebs Cycle◦ Breaks pyruvates fully into CO2, which
is released as waste
◦ Releases energy as NADH and FADH2
• Electron Transport Chain◦ Passes electrons from NADH and
FADH2 onto oxygen (“final electron acceptor”)
◦ ATP Synthase makes 32 ATP
◦ Water released as waste
Compare the basic transformation of energy during photosynthesis and cellular respiration
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Bioenergetics
PHOTOSYNTHESIS
CO2 + H2O C6H12O6 + O2
RESPIRATION
C6H12O6 + O2 CO2 + H2O
Look! They’re opposites!
Compare the basic transformation of energy during photosynthesis and cellular respiration
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Bioenergetics
• ATP = Adenosine TRI Phosphate
3
Describe the role of ATP in biochemical reactions
• Cell “Battery”
• ATP = fully charged
• ADP (adenosine di phosphate) = empty battery
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• Identify and describe the cell structures involved in transport of materials into, out of, and throughout a cell◦ Describe how the structure of the plasma membrane allows
it to function as a regulatory structure and/or protective
barrier of a cell
◦ Compare the mechanisms that transport materials across
the plasma membrane
◦ Describe how membrane-bound cellular organelles facilitate
the transport of materials within a cell
• Explain mechanisms that permit organisms to maintain biological balance between their internal and external environments◦ Explain how organisms maintain homeostasis
Homeostasis and Transport
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Homeostasis and Transport
Small, non-polar molecules can move
through membrane
Molecules which are large and in charge
cannot go through the membrane
Describe how the structure of the plasma membrane allows it to function as a regulatory structure and/or protective barrier of a cell
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Homeostasis and TransportCompare the mechanisms that transport materials across the plasma
membrane (i.e., passive transport – diffusion, osmosis, facilitated diffusion; and active transport – pumps, endocytosis, exocytosis)
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Homeostasis and TransportCompare the mechanisms that transport materials across the plasma
membrane (i.e., passive transport – diffusion, osmosis, facilitated diffusion; and active transport – pumps, endocytosis, exocytosis)
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Homeostasis and Transport
• Endoplasmic Reticulum◦ Rough: Has ribosomes on it; primarily for synthesizing polypeptides – strings of amino acids
which will be folded into proteins
◦ Smooth: No ribosomes; synthesizes lipids and can store materials
• Golgi Apparatus◦ Closely associated with the
rER; folds and assembles
polypeptides into active
proteins and packages
them into vesicles
• Vesicles◦ Can take materials from
the Golgi throughout the cell
◦ Can fuse with the cell
membrane to send materials out
of the cell, such as
neurotransmitters, hormones,
or other chemicals
Describe how membrane-bound cellular organelles (e.g. endoplasmic reticulum, Golgi apparatus) facilitate the transport of materials within a cell
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Homeostasis and Transport
• Thermoregulation (maintaining constant temperature)
◦ Too cold? Shiver, vasoconstriction – keeping blood in the core by making
blood vessels throughout the body smaller
◦ Too hot? Sweat, vasodilate – move blood to the extremities to release heat
• Water regulation (osmotic balance!) – cells must be bathed in isotonic
solutions or else they may swell or shrink
◦ Too much water? PEE!
◦ Too little water? Retain water, increase thirst
• Oxygen Regulation – O2 is necessary for cellular respiration. CO2
levels also influence pH of the blood which has an affect on enzyme
activity.
◦ Low oxygen levels / acidic pH / too much CO2? Breathe more!
Explain how organisms maintain homeostasis (e.g., thermoregulation, water regulation, oxygen regulation)
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• Describe the three stages of the cell cycle: interphase, nuclear division, cytokinesis◦ Describe the events that occur during the cell cycle:
interphase, nuclear division (i.e., mitosis or meiosis),
cytokinesis
◦ Compare the processes and outcomes of mitotic and
meiotic nuclear divisions
• Explain how genetic information is inherited◦ Describe how the process of DNA replication results in the
transmission and/or conservation of genetic information
◦ Explain the functional relationships between DNA, genes,
alleles, and chromosomes and their roles in inheritance
Cell Growth and Reproduction
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Cell Growth and Reproduction
• Interphase◦ G1: Growth◦ S: DNA replication◦ G2: Continued growth;
preparation for mitosis
• M- phase – Cell division◦ M-phase : Nuclear division
(mitosis or meiosis)● Prophase
● Metaphase
● Anaphase
● Telophase
◦ Cytokinesis: Cytoplasmic division
Describe the events that occur during the cell cycle: interphase, nuclear division (i.e. mitosis or meiosis), cytokinesis
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Cell Growth and ReproductionCompare the processes and outcomes of mitotic and meiotic nuclear
divisions
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Cell Growth and ReproductionCompare the processes and outcomes of mitotic and meiotic nuclear
divisions
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Cell Growth and Reproduction
• Helicase – unzips DNA
• DNA Polymerase – adds nucleotides to the exposed template strands
• A can only bond with T
• C can only bond with G
• The result is that
each strand is
identical to the
previous strand
Describe how the process of DNA replication results in the transmission and/or conservation of genetic information
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Cell Growth and Reproduction
• Nucleus contains DNA
• DNA is arranged into two sets of 23 different chromosomes – one set is inherited from each parent
• Each chromosome is composed of different genes◦ Each gene codes for a protein
• Homologous chromosomes
may contain the same
genes (such as eye color)
but with different versions
(blue vs. brown) –
each version is called an
allele
Explain the functional relationship between DNA, genes, alleles, and chromosomes and their roles in inheritance
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• Compare Mendelian and non-Mendelian patterns of inheritance◦ Describe and/or predict observed patterns of inheritance◦ Describe processes that can alter composition or number of
chromosomes
• Explain the process of protein synthesis (i.e., transcription, translation, and protein modification)◦ Describe how the processes of transcription and translation are similar
in all organisms◦ Describe the role of ribosomes, endoplasmic reticulum, Golgi
apparatus, and the nucleus in the production of specific types of proteins
• Explain how genetic information is expressed◦ Describe how genetic mutations alter the DNA sequence and may or
may not affect phenotype
• Apply scientific thinking, processes, tools, and technologies to the study of genetics◦ Explain how genetic engineering has impacted the fields of medicine,
forensics, and agriculture
Genetics
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Genetics
• Mendelian Genetics = Dominant / Recessive◦ Presence of one or two copies of dominant allele leads to
dominant phenotype (physical expression of gene)
◦ Must have two recessive alleles to have recessive phenotype
Describe and/or predict observed patterns of inheritance (i.e., dominant, recessive, co-dominance, incomplete dominance, sex-linked, polygenic, and multiple alleles)
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Genetics
• Co-dominance◦ Allele is expressed when
present◦ Ex: A and B blood types in
humans; “peppered chicken”
Describe and/or predict observed patterns of inheritance (i.e., dominant, recessive, co-dominance, incomplete dominance, sex-linked, polygenic, and multiple alleles)
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• Incomplete dominance◦ Heterozygous individuals
are a mix between either homozygous phenotype
◦ Ex: Red and white flower makes pink flower
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Genetics
• Sex linked◦ Gene is on X or Y chromosome◦ Females receive two Xs, males
get one X and one Y; more likely to get trait
◦ Ex: Color blindness, Haemophilia
Describe and/or predict observed patterns of inheritance (i.e., dominant, recessive, co-dominance, incomplete dominance, sex-linked, polygenic, and multiple alleles)
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• Polygenic◦ When multiple genes
control one trait
◦ Skin color
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GeneticsDescribe the processes that can alter composition or number of chromosomes (i.e., crossing-over, nondisjunction, duplication, translocation, deletion, insertion, and inversion)
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• Nondisjunction
• Causes monosomies and trisomies (Down Syndrome, Turner Syndrome)
• Crossing Over
• Mixes parent
DNA
• Other
chromosomal
mutations
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GeneticsDescribe how the processes of transcription and translation are similar in all organisms
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Genetics
RNA
• mRNA (messenger)◦ transcribed from DNA template and
carries code from nucleus to
cytoplasm;
◦ read in groups of three = codons
• rRNA (ribosomal)◦ Makes up the ribosome
• tRNA (transfer)◦ Carries amino acids to the
ribosomes to make proteins
Describe the role of ribosomes, endoplasmic reticulum, Golgi apparatus, and the nucleus in the production of specific types of proteins
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Genetics
Protein Synthesis
1. Transcription ◦ DNA acts as a template for mRNA
◦ RNA polymerase links nucleotides
together
◦ Pre-mRNA contains introns and exons;
exons are expressed, while introns interrupt, and are cut out
2. Translation◦ On ribosomes
◦ Anticodon on tRNA links to mRNA codon to bring the correct amino acid to the growing polypeptide chain
3. Modification◦ Polypeptide chains are folded into proteins by the ER and golgi into a protein’s
secondary and tertiary structures◦ Several proteins can be put together to make protein’s quaternary structure
Describe the role of ribosomes, endoplasmic reticulum, Golgi apparatus, and the nucleus in the production of specific types of proteins
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Genetics
• Mutation: Any change in DNA• Point mutation: one nucleotide is substituted, inserted or deleted◦ Silent: (has no effect on phenotype)
● Nucleotide substitution that occurs in noncoding region
● OR codon changes but codes for the same amino acid
◦ Missense:● Nucleotide substitution resulting in different amino acid
● Ex: achondroplasia dwarfism
◦ Nonsense:● Substitution causes a premature stop codon; shortened protein
● Ex: Muscular dystrophy
◦ Frameshift: ● Addition or loss of one nucleotide, causing the reading frame to shift;
all subsequent codons are read incorrectly● Ex: Cystic fibrosis, Crohn’s disease
Describe how genetic mutations alter the DNA sequence and may or may not affect phenotype (e.g., silent, nonsense, frame-shift)
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Genetics
Selective breeding:
• Allowing only those with desired characteristics to reproduce
• Most domestic animals and crop plants◦ Hybridization: crossing dissimilar individuals to get the best
traits from both
◦ Inbreeding: breeding of individuals with similar
characteristics
Explain how genetic engineering has impacted the fields of medicine, forensics, and agriculture (e.g., selective breeding, gene splicing, cloning, genetically modified organisms, gene therapy)
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Genetics
Gene Splicing:
• Combining DNA from different sources
Genetically Modified Organisms:
• Organisms with genes from other species
• Bacteria: used to produce human proteins as medications
• Animals: Make human proteins or are able to grow extra large for extra meat
• Plants: Crops have insecticide genes and grow super large
Explain how genetic engineering has impacted the fields of medicine, forensics, and agriculture (e.g., selective breeding, gene splicing, cloning, genetically modified organisms, gene therapy)
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Genetics
Cloning:
• Producing genetically identical organisms or tissue• Goal: make copies of transgenic organisms; clone tissues to allow gene therapy
Gene therapy:• Correcting a faulty or missing gene with a correctly working gene
Explain how genetic engineering has impacted the fields of medicine, forensics, and agriculture (e.g., selective breeding, gene splicing, cloning, genetically modified organisms, gene therapy)
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• Explain the mechanisms of evolution◦ Explain how natural selection can impact allele frequencies
in a population
◦ Describe the factors that can contribute to the development
of new species
◦ Explain how genetic mutations may result in genotypic and
phenotypic variations within a population
• Analyze the sources of evidence for biological evolution◦ Interpret evidence supporting the theory of evolution
• Apply scientific thinking, processes, tools, and technologies in the study of the theory of evolution◦ Distinguish between scientific terms: hypothesis, inference,
law, theory, principle, fact, and observation
The Theory of Evolution
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The Theory of Evolution
Natural Selection: Survival of the Fittest!
Explain how natural selection can impact allele frequencies in a population
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(and reproduction) Fittest: Those with the best adaptations (phenotype!) to an environment can pass their genes to offspring
Evolution = Change in allele frequency•Due to:
•Small populations•Non-random mating•Immigration / Emigration•Natural Selection•Mutations
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The Theory of Evolution
Speciation: Development of two or more daughter species from one original species
Describe the factors that can contribute to the development of new species (e.g., isolating mechanisms, genetic drift, founder effect, migration)
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• Caused by reproductive isolation: Populations of one species continue evolving without interbreeding until they are no longer able to reproduce
• Physical barriers• Reproductive barriers
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The Theory of Evolution
Genetic mutations: ◦ If beneficial: will cause allow individual to survive
◦ If harmful: will cause individual to die or have lower
reproductive success
◦ … not really sure what else to say here.
Explain how genetic mutations may result in genotypic and phenotypic variations within a population
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The Theory of Evolution
Evidence of Evolution
Interpret evidence supporting the theory of evolution (i.e., fossil, anatomical, physiological, embryological, biochemical, and universal genetic code)
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Show that species change over time
Comparative anatomy and embryology: similarities in structure and development indicate a common ancestor
Geographic distribution: Organisms that live closer together evolved from each other more recently and therefore look more similar
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The Theory of Evolution
Hypothesis: Proposed, scientifically testable explanation for an observed phenomenon
◦ Scientists test their hypotheses
Inference: assumption based on prior experience◦ Scientists make inferences based on what is already known to deduce a possible
hypothesis
Law: A generalized statement which connects may theories but does not seek to explain them
◦ Ex: Law of gravitational force; does not explain why gravity exists, simply that it does
Theory: An explanation of natural phenomena which links together many hypotheses
◦ Ex: Theory of evolution describes why fossil records are the way they are and why species distribution looks as it does
Principle: Concept based on scientific laws and axioms
Fact: An absolute truth
Observation: Direct method of gathering information
Distinguish between scientific terms: hypothesis, inference, law, theory, principle, fact, and observation
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• Describe ecological levels of organization in the biosphere◦ Describe the levels of ecological organization
◦ Describe characteristic biotic and abiotic components of aquatic and terrestrial ecosystems
• Describe interactions and relationships in an ecosystem◦ Describe how energy flows through an ecosystem
◦ Describe biotic interactions in an ecosystem
◦ Describe how matter recycles through an ecosystem
◦ Describe how ecosystems change in response to natural and human disturbances
◦ Describe the effects of limiting factors on population dynamics and potential species extinction
Ecology
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EcologyDescribe the levels of ecological organization (i.e., organism, population, community, ecosystem, biome, and biosphere)
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Ecology
• Biotic = living
• Abiotic = non-living
Describe characteristic biotic and abiotic components of aquatic and terrestrial ecosystems
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Ecology
• Producers: ◦ convert solar energy into chemical
energy◦ Use photosynthesis (usually)
◦ Basis of all food webs and food chains
• Consumers: Eat others◦ Primary consumers: Eat producers
(plants) i.e. herbivores◦ Secondary consumers: Eat primary
consumers; i.e. carnivores◦ Tertiary consumers etc: Eat
higher-level consumers
Note: Arrows point in the direction of energy flow, i.e. FROM producers TO consumers!
Describe how energy flows through an ecosystem (e.g., food chains, food webs, energy pyramids)
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Ecology
Biotic interactions: Living organisms’ interactions with one another◦ Competition: Organisms competing for similar resources
● Niche: Each species has its own niche based on what it eats,
what eats it and what nutrients and habitats it needs
◦ Predation: One organism eating another
◦ Symbiosis: Two organisms which interact with one another
● Mutualism: Both organisms benefit (ex: dog and human)
● Commensalism: One organism benefits, one is unaffected (ex:
clownfish and sea anenome)
● Parasitism: One organism benefits, one is harmed (ex:
tapeworm in human gut)
Describe biotic interactions in an ecosystem (e.g., competition, predation, symbiosis)
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EcologyDescribe how matter recycles through an ecosystem (i.e., water cycle, carbon cycle, oxygen cycle, and nitrogen cycle)
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EcologyDescribe how matter recycles through an ecosystem (i.e., water cycle, carbon cycle, oxygen cycle, and nitrogen cycle)
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EcologyDescribe how matter recycles through an ecosystem (i.e., water cycle, carbon cycle, oxygen cycle, and nitrogen cycle)
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EcologyDescribe how matter recycles through an ecosystem (i.e., water cycle, carbon cycle, oxygen cycle, and nitrogen cycle)
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Ecology
Climate change:
◦ Increased emissions of greenhouse gases; global temps rise
Nonnative species:
◦ Introducing species to a new habitat, which may outcompete native
species or grow uncontrollably due to lack of natural predator
Pollution:
◦ Biomagnification: Toxins move up trophic levels and become more
concentrated
◦ Acid rain
◦ Eutrophication: Nitrogen and phosphorus-rich compounds flow into
waterways and algae bloom, using up all oxygen and other organisms
suffocate
Describe how ecosystems change in response to natural and human disturbances (e.g., climate changes, introduction of nonnative species, pollution, fires)
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Ecology
Limiting factor: Something which prohibits the growth of a population◦ Density independent: Relies on current population size;
large populations will be limited in size
● Usually biotic factors, such as predation, disease, competition
◦ Density independent: Does not rely on population size; any
population size may be affected
● Usually abiotic factors, such as drought, hurricane, extreme
fluctuations in weather
Describe the effect of limiting factors on population dynamics and potential species extinction
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