Evolution Chapter 15

Student Performance Standards SB5. Students will evaluate the role of natural selection in the development of the theory of evolution. SB5. Students will evaluate the role of natural selection in the development of the theory of evolution. a. Trace the history of the theory.a. Trace the history of the theory. b. Explain the history of life in terms of biodiversity, ancestry, and the rates of evolution.b. Explain the history of life in terms of biodiversity, ancestry, and the rates of evolution. c. Explain how fossils and biochemical evidence support the theory.c. Explain how fossils and biochemical evidence support the theory.

Lesson Essential Question How can we observe how species have changed over time? How can we observe how species have changed over time?

Charles Darwin ( ) English Naturalist English Naturalist Sailed on the HMS Beagle from Sailed on the HMS Beagle from His job was to collect biological and geological specimens during the ship’s travels to S. America. His job was to collect biological and geological specimens during the ship’s travels to S. America. Collected rocks, fossils, plants, and animalsCollected rocks, fossils, plants, and animals

Darwin (continued) Influenced by: Influenced by: Charles Lyell - proposed that the Earth was millions of years old.Charles Lyell - proposed that the Earth was millions of years old. Thomas Malthus - predicted that one day, the human population would outgrow it’s food supply which would lead to competition for survival. Said that those better suited would survive.Thomas Malthus - predicted that one day, the human population would outgrow it’s food supply which would lead to competition for survival. Said that those better suited would survive.

Darwin Reached the Galapagos Islands in 1835: A series of islands off the coast of S. AmericaA series of islands off the coast of S. America Each island had it’s own slightly different variety of animals.Each island had it’s own slightly different variety of animals. Collected mockingbirds and finchesCollected mockingbirds and finches In 1836, John Gould classified the birds and determined them to be new species. However, the birds resembled species from mainland S. America.In 1836, John Gould classified the birds and determined them to be new species. However, the birds resembled species from mainland S. America. Darwin began to suspect populations from the mainland changed after reaching the Galapagos.Darwin began to suspect populations from the mainland changed after reaching the Galapagos. Hypothesized that new species could appear gradually through small changes in ancestral species.Hypothesized that new species could appear gradually through small changes in ancestral species.

Galapagos Islands – a series of volcanic islands off the coast of Ecuador

Jean-Baptiste Lamarck (1801) Theory of Acquired Characteristics: Theory of Acquired Characteristics: Lamarck believed that organisms change to adapt to their environment and that those changes are passed on to its offspring.Lamarck believed that organisms change to adapt to their environment and that those changes are passed on to its offspring. elephant trunk length elephant trunk length giraffe neck length giraffe neck length This theory is FALSE. Why?This theory is FALSE. Why?

Natural Selection Natural Selection Artificial Selection – Selective breeding (dogs). Artificial Selection – Selective breeding (dogs). Darwin inferred that the same process could happen in nature. Perhaps over time, this process could produce new species. Darwin inferred that the same process could happen in nature. Perhaps over time, this process could produce new species. Natural Selection – if given enough time, natural selection could modify a population enough to produce a new species. Natural Selection – if given enough time, natural selection could modify a population enough to produce a new species.

Principles for Natural Selection (Change Over Time): 1. Variations or differences within a population are visible. 2. Variations can be inherited. 3. Overpopulation = “struggle for existence” because not enough available resources for survival. 4. Variations that increase reproductive success (fitness) will have a greater chance of being passed on than those that don’t.

The Origin of Species 1859 – Darwin compiled evidence for evolution and published On the Origin of Species by Means of Natural Selection 1859 – Darwin compiled evidence for evolution and published On the Origin of Species by Means of Natural Selection Main Points: Main Points: The diverse forms of life have arisen by descent with modification from ancestral species.The diverse forms of life have arisen by descent with modification from ancestral species. The mechanism of modification has been natural selection working over enormous tracts of time.The mechanism of modification has been natural selection working over enormous tracts of time. Darwin used the term evolution only on the last page. Darwin used the term evolution only on the last page.

What is Evolution? - Any change in the relative frequencies of alleles in a population’s gene pool. - Evolution works on populations not individuals. - Evolution is CHANGE OVER TIME.

Support for Evolution 1. Fossil Record:

GlyptodontsArmadillos

2. Comparative Anatomy - the study of similarities and differences in the anatomy (body plan) of an organism: a. Homologous Structures – anatomically similar structures inherited from a common ancestor. b. Vestigial Structures – structures that are the reduced forms of functional structures in other organisms. (see Table 15.2, page 425) c. Analogous Structures – not inherited through common ancestors.

Homologous Structures

Vestigial Structures The wings of kiwis are too small to be of any use in flight. Snake Pelvis Appendix

Analogous Structures Wing of an eagle and the wing of a beetle have the same function but are constructed in different ways from different material.

3. Comparative Embryology – vertebrae embryos exhibit homologous structures during certain phases of development but become totally different structures in the adult form. 1. Head 2. Pharyngeal Pouches 3. Tail Bird EmbryoHuman Embryo

4. Comparative Biochemistry – scientific data shows that common ancestry can be seen in metabolic molecules: - cytochrome c (see Fig. 15.9, page 427) - DNA/RNA - other proteins, as well

5. Geographic Distribution – of plants and animals - Darwin observed that animals on the S. American mainland were more similar to other S. American animals than they were to animals living in similar environments in Europe.

Ratite Birds

PBS Video Clips ators/teachstuds/svideos.html ators/teachstuds/svideos.html ators/teachstuds/svideos.html ators/teachstuds/svideos.html Watch “Isn’t Evolution Just a Theory?” Watch “Isn’t Evolution Just a Theory?” Watch “Who Was Charles Darwin?” Watch “Who Was Charles Darwin?”