Introduction into evolution (click Picture)

1. Introduction into evolution (click Picture)

2. Evolution Notes What can account for the diversity of life? • Evolution—change over time; process by which modern organisms have descended from ancient organisms

3. Theories of Evolution • Lamarck—Theory of Acquired Characteristics • By selective use or disuse of organs, organisms acquired or lost certain traits during their lifetime; these traits could then be passed on to their offspring Example: Giraffe could not reach the leaves so it stretched it’s so that all of its offspring had long necks. Problem: Did not know how traits were inherited— GENETICS (meiosis!!!)

5. Over timenatural selection results in changes in the inherited traits of a population • Darwin—Evolution by Natural Selection

6. You inherit blue eyes or curly hair from your parents. You acquire athletic skills or the ability to play a musical instrument

8. Darwin’s Influences A. Made observations in Galapagos Island as a naturalist-(travelled on a boat called HMS Beagle) Observations made: • Similar species well suited to the environment they inhabited (lived in). • Traits of similar species varied noticeably among different islands of the Galapagos Example: Darwin’s finches and tortoises

12. B. Hutton and Lyell (studied geology) • Helped scientists recognize that Earth is many millions of years old; older than anyone believed C. Malthus (studied human populations) • If the human population continued to grow unchecked, sooner or later there would be insufficient living space and food for everyone creating a struggle to survive

13. Farmers and Artificial Selection—Nature provided the variation among organisms and humans selected for the variations they found useful • Example: Farmer breeds largest hogs for most meat production.

14. Darwin’s Theory of Evolution by Natural Selection A. Struggle for existence—more offspring are produced than can survive; therefore, members of each species compete regularly to obtain food, living space, and other necessitiesof life

15. B. Survival of the Fittest (also called Natural Selection)—individuals with an adaptation (genetic difference) that makes them more “fit” for a certain environment will survive and reproduce; those not suited will die or produce few offspring

16. C. Descent with modification- each living species has descended, with changes, from a common ancestor • D. Darwin’s conclusions are published in a book called “Origin of Species”

18. Evidence of Evolution(5 different types) A. Fossil record- examples of many species that have lived for a time and then became extinct

19. B. Geographical Distribution of living species— when looking at similar environments on different continents, different animals had similar anatomies and behavior because of adaptation

20. Geographical Distribution of Species Beaver Beaver Muskrat Beaver andMuskrat Coypu Capybara Coypu andCapybara Muskrat Capybara Coypu

21. C. Homologous body structures—structures that have different mature forms but develop from the same embryonic tissues; provide strong evidence that all four-limbed vertebrates have descended, with modifications, from common ancestors Comparative anatomies realized that although these vertebrates evolved in different directions, with changes in size, shape, and function, they all used common bone elements, as well as homologous nerve systems, blood circulatory systems, and other organ systems, thus indicating a common vertebrate ancestor. In contrast to teleological explanation that emphasize design for particular function, the vertebrate forelimb uses a common underlying ancestral structure for different functions.

22. Homologous Body Structures Turtle Alligator Bird Mammal Ancient lobe-finned fish

23. D. Vestigial organs—organ that serves no useful function in an organism. (i.e. wisdom teeth, tail bone, appendix?)

24. E. Similarities in embryology—early stages, or embryos, of many animals with backbones are very similar

26. Evidenceof Populations • Populations—all individuals of a species that live together in one area B. Gene pool—consists of all genes, including all the different alleles that are present in a population

27. Sources of Genetic Variation (Where do inheritable differences come from?) • Mutations—change in a sequence of DNA • Gene shuffling—occurs during the independent assortment of chromosomes and crossing over of genes during meiosis

28. D. Process of speciation or how new species form • Species determined by organisms that reproduce naturallyonly with each other • As new species evolve, populations become reproductivelyisolated from each other.

30. Behavioral Isolation—two populations are capable of interbreeding but have differences in courtship rituals or other reproductive strategies that involve behavior. Eastern meadowlarks will not respond to western meadowlark mating songs. Western meadowlark Eastern meadowlark

31. b. Geographic Isolation—two populations are separated by geographic barriers such as rivers,mountains, or bodies of water

32. c. Temporal Isolation—two or more species reproduce at different times 3 similar species of orchid live in the same rain forest. Each species releases pollen only on a single day. Because the 3 species release pollen on different days, they cannot pollinate (reproduce with) one another.

34. Understanding Phylogenies—Evolutionary Classification Darwin’s ideas about descent with modification have given rise to the study of phylogeny, or evolutionary relationships among organisms.

35. Phylogenies—study of evolutionary relatedness among various groups of organisms • (ex: species, populations) • Biologists now group organisms into categories that represent lines of evolutionary descent not just physical similarities. • The strategy of grouping organisms together based on their evolutionary history is called evolutionary classification. • Relatedness based on measuring similarity ofDNA in the genome of the organisms.

37. Understanding a phylogeny is a lot like reading a family tree. The root of the tree represents the ancestral lineage, and the tips of the branches represent the descendents of that ancestor. As you move from the root to the tips, you are moving forward in time.

38. When a lineage splits (speciation), it is represented as branching on a phylogeny. When a speciation event occurs, a single ancestral lineage gives rise to two or more daughter lineages. Speciation—to form a new biological species from an existing one

39. Phylogenies trace patterns of shared ancestry between lineages. Each lineage has a part of its history that is unique to it alone and parts that are shared with other lineages.

40. Similarly, each lineage has ancestors that are unique to that lineage and ancestors that are shared with other lineages — common ancestors.

41. Trees, not ladders Several times in the past, biologists have committed themselves to the incorrect idea that life can be organized on a ladder of lower to higher organisms. • Similarly, it's easy to misinterpret phylogenies as implying that some organisms are more "advanced" than others; however, phylogenies don't imply this at all.

42. In this highly simplified phylogeny, a speciation event occurred resulting in two lineages. One led to the mosses of today; the other led to the fern, pine, and rose. Since that speciation event, both lineages have had an equal amount of time to evolve. So, although mosses branch off early on the tree of life and share many features with the ancestor of all land plants, living moss species are not ancestral to other land plants. Nor are they more primitive. Mosses are the “cousins” of other land plants.

43. So when reading a phylogeny, it is important to keep three things in mind: • Evolution produces a pattern of relationships A B C D among lineages that is tree-like, not ladder-like. • 2. Just because we tend to read phylogenies from left to right, there is no correlation with level of "advancement." • 3. For any speciation event on a phylogeny, the choice of which lineage goes to the right and which goes to the left is random. The following phylogenies are equivalent:

44. Misconceptions about Humans The points described above cause the most problems when it comes to human evolution. The phylogeny of living species most closely related to us looks like this: • It is important to remember that: • Humans did not evolve from chimpanzees. Humans and chimpanzees are evolutionary “cousins” and share a recent common ancestor that was neither chimpanzee nor human. • Humans are not "higher" or "more evolved" than other living lineages. Since our lineages split, humans and chimpanzees have each evolved traits unique to their own lineages.

49. Linnaeus’ Classification System • What is a species? • A population of organisms that share similar characteristics and can breed with one another and produce fertile offspring. What are some examples of species? Dogs, Cats, Humans,etc. • B. How many species have scientists identified (about 1.5 million) and how many have yet to be discovered? Between 2 and 100 million

50. 2. Why classify organisms? • Biologists must attempt to organize livingthings into groups that have biological meaning. • B. To study the diversity of life, biologists use a classificationsystem to name organisms and group them in a logical manner. • C. The study where scientists classify organisms and assign a universally accepted name is called taxonomy. • D. By using a scientificname, biologists can be certain that everyone is discussing the same organism. • E. Scientists organize organisms into groups that have biological significance. • In a good system of classification, organisms placed into a particular group are more similar to each other than organisms in other groups.