Evidence for Evolution Genetic change over time in a population = 6 lines of evidence you should know: Artificial Selection Adaptations Fossils Anatomy Embryology Biochemistry Evolution!! 1

Evidence for Evolution discussion: What is evidence?

Similar to Natural Selection but done by humans to select traits… http://www.youtube.com/watch?v=EoB0pdhxfZs Silver fox experiment http://www.youtube.com/watch?v=0jFGNQScRNY 1. Artificial Selection Selective Breeding of organisms to produce offspring with desired traits (has been around since ancient times) Similar to Natural Selection but done by humans to select traits…

Exit Questions (Full sentence answers!) What is artificial selection, in your own words? Compare and contrast artificial selection and natural selection. Why is artificial selection considered to be evidence for evolution? Explain

2. ADAPTATIONS AN ADAPTATION IS ANY Genetic VARIATION THAT AIDS AN ORGANISM’S CHANCES OF SURVIVAL IN ITS ENVIRONMENT.

Structural Adaptations FOR EXAMPLE – A GIRAFFE’S NECK http://www.youtube.com/watch?v=ktIGVtKdgwo venus fly trap http://www.youtube.com/watch?v=ymnLpQNyI6g venus fly trap 2

Exit Questions (Full sentence answers!) Describe how the modified leaves of the Venus fly trap and the pitcher plant help them to survive in their environment. These modified leaves are great adaptations for a swampy bog, but they are not beneficial in all environments. Why don’t all plants need to have these types of modified leaves? Explain.

Mimicry A STRUCTURAL ADAPTATION THAT ENABLES ONE SPECIES TO RESEMBLE ANOTHER SPECIES. Two Types: Batesian– harmless species resembles a harmful species. (viceroy butterfly) Mullerian– harmful species resemble each other (wasps, bees, etc.)

Camouflage Photo courtesy David Parks A cryptic frog - This species has developed a coloring, texture and form that are similar to the leaves found in its environment. A STRUCTURAL ADAPTATION THAT ENABLES A SPECIES TO BLEND WITH THEIR SURROUNDINGS.

Exit Questions (Full sentence answers!) Compare and contrast mimicry and camouflage, giving an example of each to support your explanation. Stick bugs resemble sticks in order to blend in with their environment and avoid predation (getting eaten). Is this mimicry or camouflage? Explain.

Fossil: A remnant or trace of an organism from long ago… 3. FOSSILS Fossil: A remnant or trace of an organism from long ago… TRACE FOSSILS CASTS PETRIFIED FOSSILS

IMPRINTS AMBER PRESERVED FROZEN MOLDS

Analyzing fossils Hard body parts are more likely to become fossils Fossils are usually found in sedimentary rock Law of superposition– The older layers of rock will be deeper than newer layers of rock. Fossil animation: http://www.classzone.com/books/earth_science/terc/content/visualizations/es2901/es2901page01.cfm Fossil animation: various ways to fossilize http://www.bbc.co.uk/sn/prehistoric_life/dinosaurs/making_fossils/

Which layer is oldest? Youngest? Notice the differences in species.

Important thought Question How would you recognize a Mass extinction in the fossil record? Mass extinction Video (13 min.) http://www.pbs.org/wgbh/nova/sciencenow/3318/01.html (link works in Chrome) http://www.wgbh.org/programs/Nova-ScienceNow-390/episodes/Mass-Extinction-6556 (alternative link) http://www.pbs.org/wgbh/evolution/library/03/2/l_032_02.html Permian-Triassic extinction fossil record.

Dating Fossils Relative Dating = Comparing location of fossil in rock strata to determine whether it is older or younger than other fossils Absolute Dating = Radiometric dating gives age in years. Uses the half lives of radioactive isotopes to estimate age.

Geologic time scale The earth is thought to be 4.6 billion years old. http://www.pbs.org/wgbh/evolution/library/03/3/l_033_01.html Radiometric dating video

T-Rex Blood? http://www.pbs.org/wgbh/nova/nature/t-rex-blood.html Exit Questions: Why is this discovery useful to understanding dinosaurs? How is it thought that these soft tissues were preserved?

Transitional Forms Fossils or organisms that show the intermediate states between an ancestral form and that of its descendants

Transitional Forms Video clip: Transitional Tetrapod Fossil: http://www.pbs.org/wgbh/evolution/library/03/4/l_034_49.html Exit Questions: What is a transitional form? Why is the fossil in the video considered to be transitional? Describe.

4. ANATOMY Anatomy = Body Structures 3 types (see next slides)

Homologous Structures Structures thought to have common origin that are similar in structure, but modified for different functions Homologous Structures Alligator Cat Whale Bird Human Bat

Analogous Structures Similar function, but different origin Example – wings on a bird & butterfly

Vestigial Structures Body structures that are of little to no use in a modern organism. Examples: Appendix Wisdom teeth Thigh bones in snakes & whales

Exit Questions Explain the difference between homologous, analogous and vestigial structures giving an example of each in your explanation.

Homologous vs. Analogous Virtual Lab http://evolution.berkeley.edu/evolibrary/article/0_0_0/similarity_ms_01 Get computer lab to do this!

FISH CHICK PIG HUMAN 5. EMBRYOLOGY THE SIMILARITIES AMONG THE YOUNG EMBRYOS MAY SUGGEST EVOLUTION FROM A DISTANT, COMMON ANCESTOR. FISH CHICK PIG HUMAN http://www.pbs.org/wgbh/evolution/library/04/2/l_042_02.html

6. BIOCHEMISTRY Comparisons of the DNA, RNA, or proteins of different species produce biochemical evidence for evolution. Common Genetic Code: http://www.pbs.org/wgbh/evolution/library/04/4/l_044_02.html Genetic Tool kit: http://www.pbs.org/wgbh/evolution/library/03/4/l_034_04.html

Explain how biochemical evidence may provide evidence for evolution.   Describe the biochemical evidence discussed in the videos and the inferences derived from this evidence in a chart like this:  Evidence (The Facts) Inferences (interpretation)

Theories of how evolution may occur gradualism—slow, gradual build-up of adaptations punctuated equilibrium— evolution occurs in fast bursts followed by long periods of genetic equilibrium.

Exit Question Compare and contrast punctuated equilibrium and gradualism.

End of evidence portion These next slides were originally the beginning of the presentation. (Darwin and Natural selection) Used other ppt. for this part.

Just for Fun! Linguistic Evolution: French --> Southern Accent

THE THEORY OF EVOLUTION CHARLES DARWIN 1809-1882

The voyage of the HMS Beagle 1831, when Darwin was 21 years old

CHARLES DARWIN WAS A NATURALIST WHO STUDIED & COLLECTED BIOLOGICAL SPECIMENS AT EVERY PORT ALONG THE SHIP’S ROUTE.

DARWIN’S OBSERVATIONS LED HIM TO CONSIDER THE POSSIBILITY THAT SPECIES CAN CHANGE OVER TIME. HIS IDEA WAS CALLED: NATURAL SELECTION

Species change over time Natural Selection Species change over time Organisms produce more offspring than can survive. 2. In any population individuals have variations. 3. Individuals with certain useful variations survive in their environment, passing those variations to the next generation. 4. Over time, offspring with certain variations make up most of the population and may look entirely different.

MECHANISM FOR CHANGE IN POPULATIONS NATURAL SELECTION MECHANISM FOR CHANGE IN POPULATIONS