Biology I Chapter 15

1. Biology I Chapter 15 Theory of Evolution

2. Do Now • What is the estimated age of the Earth? • 4 billion years

3. Review Genotype-genetic information for one or many genes AA Aa aa Phenotype-outward expression of genotype Hair color

4. Theory Theory-a well-supported explanation for some aspect of the natural world that incorporates many observations, inferences, and tested hypotheses.

5. George Cuvier Reconstructed the appearance of unique organisms from fossil bones Extinct-A species that has disappeared permanently

6. Charles Lyell Uniformitarianism-states that the geologic processes that shaped Earth in the past continue to operate in the same way today

7. Jean-Baptiste Lamarck Inheritance of acquired characteristics-individuals acquire traits during their lifetime as a result of experience or behavior and then pass those traits to offspring.

8. Charles Darwin English Naturalist December 1831-HMS Beagle Galapagos Islands Evolution-A heritable change in a species over time 1859-”Origin of the Species”

9. Do Now • What does HMS stand for?

10. Darwin’s Ideas Descent with Modification-the term used by Darwin to describe the process of evolution.

11. Natural Selection Natural selection-the process by which organisms with traits well suited to their environment survive and reproduce more successfully than organisms less suited to the same environment.

12. Natural Selection 1. Overproduction 2. Genetic Variation 3. Struggle to Survive Adaptation- The process by which a population becomes better suited to its environment 4. Differential Reproduction

13. Natural Selection Fitness-a measure of an individual’s hereditary contribution to the next generation.

14. Do Now The theory of endosymbiosis provides a possible explanation for how eukaryotic cells came into existence. The presence of chloroplasts in photosynthetic organisms is one phenomenon explained by this theory. Based on the theory of endosymbiosis, what was the significance of the development of chloroplasts? • A. The development of chloroplasts caused a large increase in carbon dioxide levels in Earth's atmosphere, which allowed the evolution of organisms that perform cellular respiration. • B. The development of chloroplasts led to the oxygenation of Earth's atmosphere, which allowed the evolution of more complex oxygen-breathing organisms. • C. The development of chloroplasts caused a large increase in the amount of water on Earth, which led to the existence of living organisms. • D. The development of chloroplasts led to the initial formation of DNA, which allowed organisms to replicate through asexual reproduction.

15. Fossils Fossil-the remains or traces of an organism that died long ago Shells or old bones Any traces of dead organisms Insects trapped in tree sap

16. Fossil Formation Animal fossils may form when: An animal is buried by sediment An animal is buried on the ocean floor, in swamps, in mud, or in tar pits An animal’s tissue is replaced by harder minerals (petrification).

17. Fossils Relative Age-a fossil’s age compared to that of other fossils Absolute Age-the time since formation

18. Fossils Transitional species-have features that are intermediate between those of hypothesized ancestors and later descendant species.

19. Do Now • The instructions for building proteins necessary for all life functions are coded within an organism's genetic code. The genetic code of an organism consists of codons, or sequences of three nucleotides, that each code for a specific amino acid. Amino acids are the building blocks of proteins. • The amino acids coded by specific codons • A. are different for every organism on Earth. • B. differ between plants and animals. • C. differ between members of different species. • D. are almost universal among all living things.

20. Biogeography Biogeography-the study of the locations of organisms around the world

21. Anatomy and Embryology The study of embryological similarities and differences among species is called comparative embryology.

22. Anatomy and Embryology The diagram below shows a variety of animals at different stages of development. Which of the following statements is supported by this diagram? A. Humans undergo more stages of development than other animals, such as salamanders, tortoises, chickens, and pigs. B. The developmental stages of animals are radically different; they do not possess any similarities at all. C. There are similarities in the developmental stages of different organisms in the animal kingdom. D. Diverse organisms in the animal kingdom possess more similarities during the fetal stages of development than during their embryonic stages.

23. Anatomy and Embryology Homologous structures-structures are similar because they originated in a common ancestor (Same structure; different function) Ex. Human arm, Penguin wing, Alligator leg, Bat wing Cat Bat Whale Human

24. Anatomy and Embryology Analogous structures-have closely related functions but do not derive from the same ancestral form. (Different structure; same function.) Ex. Bird, bat, and moth wings

25. Anatomy and Embryology Vestigial Structure-Anatomical structures that appear to be derived from a functional structure in an ancestor, but that currently do not serve an important function Ex. Human tailbone & appendix

26. Biological Molecules Comparative biochemistry is the study of similarities and differences in DNA sequences among organisms. Organisms share proteins & nucleic acids. Organisms that share many traits should have a more recent common ancestor than organisms that share fewer traits. Ex. The occurrence of the same blood protein in a group of species provides evidence that these species descended from a common ancestor.

27. Do Now • The following data table summarizes the number of differences in amino acid sequences found for four different species. • Amino Acid Dissimilarities • for Beta Hemoglobin Protein • Based on the data table, which two species are most closely related? • A. species B and species C • B. species B and species D • C. species C and species D • D. species A and species B

28. Developing Theory Modern Synthesis: closely related species will show similarities in amino acid & DNA sequences. If species have changed over time, their genes should have changed. Phylogeny-relationships by ancestry among groups of organisms. Fossil evidence, anatomical evidence, DNA, and other molecular evidence to model

29. Phylogenetic Tree- shows a hypothesized phylogeny. Developing Theory

30. Evolution in Action Convergent Evolution-different species evolve similar traits (analogous structures) Divergent Evolution-the accumulation of differences between populations that once formed a single population (homologous structures).

31. Divergent Evolution W X Y Z The figures above show the forelimb structure of four extinct species of crawling animals. The circles represent wrist bones, and the digits extend from the wrist. All living descendants of this group have three digits attached to a single wrist bone. Based on the evidence provided, which species diverged from the common ancestor earliest? A. W B. X C. Y D. Z

32. Evolution in Action Adaptive Radiation-a new population in a new environment will undergo divergent evolution until the population fills many parts of the environment.

33. Artificial Selection Artificial Selection-a human breeder chooses individuals that will parent the next generation Speeds up the process of divergent evolution.

34. Coevolution Coevolution-occurs as two or more species change over time due to each other’s influence

35. Cut W Cut X Cut Y Cut Z • The figures above show four vertical cuts through different canyons. The top layer is the youngest layer, and the bottom layer is the oldest. In the layers are fossils of shellfish. Which cut would be possible evidence that a circular shellfish evolved from a hexagonal shellfish? • A. Cut W C. Cut Y • B. Cut X D. Cut Z

36. Why did Darwin think that the finches he observed and collected in the Galapagos Islands shared a common ancestor? Essay

37. Write 3 lines explaining natural selection. Do Now