Prehistory 2: Life Changes- Notes on adaptation, natural selection, speciation, & Darwin, with...

transcript

Prehistory 2: Life Changes

ppt. by Robin D. Seamon

DEFINITIONS:

Adaptation- physical characteristic or behavior that allows an organism to survive and reproduce in its environment

Species- group of organisms that can mate to produce fertile offspring

population- groups of same species living in the same place

evolution- process in which inherited characteristics within a population change over generations such that new species sometimes arise

Fossil- remains or imprints of once-living organisms found in layers of rock

Fossil record- historical timeline based on fossils found in Earth’s crust

CONNECTING:

* Fossils are hard to form & find (esp. on land) * There are blank places in our record * Disturbances in the strata/rock record

1858: 1st almost complete dino skeleton found

HOW DO FOSSILS FORM?

Petrified Fossil: fossil completely turns to stone

1. Organism dies in right place: sediments cover (lake bottom, mud flats)

2. Soft parts decay or are eaten3. Sediments layer; pressure causes sediments to

fuse together, encasing organism like a shell4. Ground water with minerals seeps around the

bones; minerals left in bone spaces & may replace whole bone

5. Rock layer needs uplifted & layers above eroded for fossil to be DISCOVERED

Scientists use logic & carbon dating to sequence & draw connections among fossil findings all over the world

http://abyss.uoregon.edu/~js/lectures/age_of_the_earth/age_of_the_earth.html

What do scientists do?

Geologists & Paleontologists

Compare skeletal structure

Compare DNA

Date the fossils

Put into logical order as new fossils are found

http://www.ucmp.berkeley.edu/fosrec/McKinney.html

Which rocks are oldest? Most recent?

Which fossils would be oldest? Most recent?

A: Most recent rocks- Those on top & those cutting through others

Rocks on the top & those intruding are the youngest.

Rocks on the bottom are older.

Erosion on a layer with other layers piled on top means the eroded layer is older.

Erosion means an environmental change: physical weathering-wind, water, temperature

SIMILAR STRUCTURE? = TWO REASONS:

Analogous structures performs same function; evolved from different origins (independently)

WINGS: birds, bats, butterflies

Homologous structures same structure, different function; evolved from common ancestor

human arm, horse leg, bird wing

ADVANCE

Analogous Structures

http://web1.d25.k12.id.us/home/staff/rudeer/homoanalvestig.html

Homologous Structures

BACKhttp://itc.gsw.edu/faculty/bcarter/histgeol/paleo2/homol1.htm

EXAMPLE:

Evolution

p. 619http://evolution.berkeley.edu/evosite/evo101/images/whaleancestors.gif

Similar skeletal features reveal important evolutionary linksamong vertebrates. Structures such as bones that have a commonorigin but different function are called homologous structures.

COMPARING SKELETONS LABHomologous structure- body part with same origin in different species but may not serve the same functions now.DIRECTIONS: Color the homologous bones the same color in each species.

Header: CS 1

Activity 1:

Activity 2: Choose 3 colors. Decide which skeletons appear most similar. Color similar skeletons the same color.

COMPARING SKELETONS LAB 2

http://www.indiana.edu/~ensiweb/lessons/gr.fs.fd.html

Make a poster to show your final interpretation of the fossils as well as how your interpretation changed as you got more information.Each person’s handwriting must be on the poster.

Include in your poster:• The type of animal you think your fossils were• A drawing of what the animal might look like• Where the animal might have lived (in water, on land, on land and in the air) and whyyou think so• What you originally thought the animal was on Day 1• The biggest piece of evidence that caused you to change your interpretation from

Day1 to Day 5• What new pieces of evidence (such as another fossil from the animal) might support

your hypothesis about these fossils?• What new piece of evidence might prove that your interpretation of these fossils isinaccurate?

The Great Fossil Find Lab

A HISTORY LESSON:

Charles Darwin: 1809- 1882, naturalist who voyaged on the HMS Beagle as a young man & is know as the founder of the idea of natural selection later in life…

…really a THINKER, who put together the ideas of many contemporaries.

www.victorianweb.org/science/darwin/index.html

• He collected plant and animal samples, esp. off the coast of Ecuador in the Galapagos Islands

http://upload.wikimedia.org/wikipedia/commons/4/42/Voyage_of_the_Beagle.jpg

VIDEO: Galapagos Island 3 min

• Noticed that plants and animals on the islands looked similar to those in Ecuador with minor variations (differences)

• This got him to thinking

The beaks were suited to what

the birds ate on each island!

: www.biology-online.org/2/11_natural_selection.htm

• traits- specific characteristics that can be passed from parent to offspring through genes

• Genes-What is DNA? HSW VIDEO DNA Videos 3 min

An example:

• Selective breeding- humans select desired traits in plant/animal and breed it for more (150+ breeds of dogs)

• Thomas Malthus wrote An Essay on the Principle of Population: an essay that said humans had the potential to reproduce too fast for the food supply

• Said that human populations are LIMITED to choices humans make & available resources/disease

Malthus POPULATION EGG CARTON STUDY

READ Book: The Global Village

Add popcorn kernels to the rows as follows:

TOP Food Supply: 1, 2, 3, 4, 5, 6

BOTTOM Human Population: 1, 2, 4, …

• Darwin thought then, that populations of all species were limited:

• Starvation

• Disease

• Competition

• Predation

• So, only a limited number survive to reproduce

What was special about the survivors?

• Offspring inherit traits to survive in the environment

• Darwin thought species could evolve over time ***MOST geologists at that time thought the Earth wasn’t old enough for that

What was special about the survivors?

• Charles Lyell a geologist, wrote Principles of Geology; said Earth was formed by natural processes over a LONG period of time

• Darwin struggled with ideas for 20 yrs

• Alfred Russell Wallace 1858 a naturalist, writing to Darwin; shared the same ideas

• 1859 Darwin published his ideas: On the Origin of Species by Means of Natural Selection

• Natural Selection process by which individuals are better adapted to survive and reproduce than others & pass along those genes to offspring

• Theory lacked some evidence, but later scientists filled in the holes

1. Overproduction: producing more potential babies than will survive

2. Inherited variation: each individual is slightly different, not exactly like parent

3. Struggle to survive: some will die, disease, competition, predators, but ALL won’t

4. Successful reproduction: those most adapted to environment will have offspring with traits like them

ADVANCE

• PICTURE

VIDEO 1 Evolution of organic life 2 min VIDEO 2 Natural Selection 2 min

ADVANCE

Natural Selection

http://evolution.berkeley.edu/evolibrary/article/bergstrom_02

• Tusk-less elephants are proving beneficial against poachers & are living to reproduce offspring without tusks as well

EXAMPLES:

African Elephant

http://www.wildlife-pictures-online.com/elephant_epkp4.html

HSW- LINK (elephant evoln) 4 min

• During Industrial Revolution, soot covered the trees in Europe. White moths stood out & were eaten; black moths reproduced & white moths almost gone

EXAMPLES:

Peppered moth

http://sisu.typepad.com/sisu/pepperedmothslichen.jpg

www.amentsoc.org/about/news/0111/

http://radaractive.blogspot.com/2009/07/in-regards-to-canards-natural-selection.html

• Pesticide resistance: resistant individuals live to reproduce & pass on resistant genes. Insects produce LOTS of offspring

EXAMPLES:

http://www.grapes.msu.edu/images/pesticResist.gif

www.grapes.msu.edu/pesticideResist.htm

• Super viruses

• Same flu shots not work each year

• Antibiotic resistance

EXAMPLES:

virusBacteria: staph

www.healthheap.com/tag/bacteria http://health.howstuffworks.com/medicine/modern/light-virus.htm

• Speciation formation of a new species; species become so different, they can’t mate any longer

• Separation new adaptation can’t mate when go

back to originalpopulation

SEPARATORS:

Canyon

Mountain range

humans

VIDEO: Evolution Adaptation 2 min

VIDEOS:Discovery Education: Greatest Discoveries with Bill Nye: The Origin & Evolution of Life pr25173 35 min DISC LINK

HSW- LINK (evolution) 20 min

Earth’s geologic History LINK (30 min)