2. Ch. 14 Evolution Evolution : the process of change that produces new species from already existing species. Change in a species due to mutation of the DNA code that occurs over a long time. evolution: generation-to-generation change in the proportion of different inherited genes in a population that account for all of the changes that have transformed life over an immense time.

3. Species – group of closely related organisms that can mate and produce fertile offspring. Adaptation: inherited characteristic that improves an organism's ability to survive and reproduce in a particular environment.

4. Evolution of Air Breathing:

5. Evolution of Brains:

6. Early Ideas about Evolution Originally people thought that the species on Earth were permanent – the same species had always been here. They also thought that the Earth wasn’t that old – less than 10,000 years old. In the 1700’s, people began to find fossils. The discovery of fossils meant the Earth might be much older than thought. It was also noted that the fossils were different from known living creatures, and that different living species were often similar to each other while not being exactly the same.

7. Lamark’s early theory of evolution Lamark had the idea that species change over time. Evolution involves adaptations

8. Lamark’s Theory Species adapt because of what they need or want. Use of structure results in evolution – called “acquired characteristics”. acquired characteristics are passed on to next generation. Lamark’s theory is no longer accepted, but he was the first to suggest that evolution occurs and that it is related to adaptations.

9. Darwin’s Theory of Evolution 1859 - Charles Darwin publishes The Origin of Species.

10. Darwin’s Voyage on “Beagle” shaped many ideas of Biology Purpose of voyage – Sail around world & survey little known coastal areas HMS Beagle Voyage 1835

11. Charles Darwin Natural Selection: “Survival of fittest” Competition for resources Best adapted species survive The Fittest reproduce natural selection: process by which individuals with inherited characteristics well-suited to the environment leave more offspring than do other individuals

12. Darwin’s key ideas: A. REPRODUCTION: Organisms produce more offspring than can survive B. VARIATION:Variety in traits exist C. SURVIVAL OF THE FIT: Some traits allow survival & are passed on D. Over time certain variations make up most of a population & they may be different from their ancestors

13. Evolution Evidence: 1. Adaptations 2. Fossils 3. Comparative anatomy 4. Comparative embryology 5. Comparative Biochemistry 6. Plate Techtonics

14. 1.Adaptations: features suited to a particular environment that allow organisms to survive. Inuit people, who live in the extreme cold of the Arctic, have short, stout bodies that conserve heat.

15. Masai, people,who live in the arid lands of eastern Africa, have tall, lean bodies that disperse heat well.

16. Plant Adaptations: Venus Fly Trap Captures Animals Acquires Minerals For Photo- synthesis Help!!!

17. Leaf Adaptations: Succulents Thick Store Water Prevent Drying out

18. Leaf Adapatations: Pine Needles Shed snow Less water loss Reduced surface area Tolerate wind

19. 2. Fossil Evidence : Once living remains of organisms Limited: 1.Type of material preserved (bone, shell, impressions, amber) 2.Incomplete record 3.Easily disrupted

20. Plant Fossil:

21. 3. Comparative Anatomy: Structural similarities link related species

22. Comparative Anatomy Structures: Analogous: 1.Different ancestors 2.“analogy”=like 3.Different underlying structures 4.Same Function 5.Similar Environments Homologous: 1.Same ancestor 2.“homo”=same 3.Same underlying structures 4.Different Functions 5.Different Environments

23. Analogous Structures Different underlying structures (different ancestors) Same function, similar environments Fly wing Bird Wing

24. Homologous Structures: Same underlying structures, different functions, different environments & common ancestor Bird Wing Porpoise Flipper

25. 4. Comparative embryology : Similar embryo development in closely related species

26. 5.Comparative Biochemistry Similar DNA sequences= Similar Gene segments of the DNA Code for similar traits In closely related species

27. 6. Plate Techtonics Geological theory: Continental masses were one land mass that explains Closely related species have common ancestors on now separated continents

28. 14.3 population: group of individuals of the same species living in a particular area at the same time. Over time, the isolated populations would become more and more different. In the Galapagos islands, an original species of finch eventually spread out to the separate islands. variation: difference among members of a species And over many generations, the populations could become different enough to be separate species.

29. artificial selection: selective breeding of domesticated plants and animals to produce offspring with desired genetic traits. Sometimes artificial selection occurs when we don’t want it to. Examples of this include: insect populations that become resistant to pesticides germs that become resistant to antibiotics Artificial selection supports the idea that evolution could have created different species.

30. 14.4 Microevolution – genetics and natural selection. gene pool: all of the alleles in all the individuals that make up a population. microevolution: evolution on the smallest scale – the generation-to-generation change in the frequencies of alleles within a population

31. Gene pool Group of reproducing organisms Specific frequency of allele types: 25% AA 50% Aa 25% aa

32. Changes in the Gene Pool: New mix of allele frequencies: 10% aa 60% Aa 30% AA

33. Hardy-Weinberg equilibrium: condition that occurs when the frequency of alleles in a particular gene pool remain constant over time. When the frequency of alleles does not change, evolution is not occurring. Usually though, the allele frequencies change over time. This is called genetic drift.

34. genetic drift: change in the gene pool of a population due to chance. Genetic drift results from random mating and the randomness of meiosis in producing the genes in eggs and sperm. Genetic drift has the greatest effect on small populations.

35. The Bottleneck effect – when a natural disaster greatly reduces the size of a population. This can greatly change the allele frequencies. The Founder effect – when a few members of a population colonize a new area, genetic drift may greatly increase in the new area. Two special examples of genetic drift:

36. Genetic drift and natural selection change the gene pool’s frequency of alleles the most. Other processes that change the gene pool are: gene flow: exchange of genes between populations. mutations: changes in an organisms DNA. If mutations occur in gametes, they may introduce new genes into the population.