EVOLUTION AND CLASSIFICATION

1. EVOLUTION AND CLASSIFICATION Biology EOC Boot Camp April, 2013 created by David Campbell

2. SC.912.L.15.1 Explain how the scientific theory of evolution is supported by the fossil record, comparative anatomy, comparative embryology, biogeography, molecular biology, and observed evolutionary change.

3. Evolution is defined as the change in a population of organisms over time.

4. Evidence for evolution shows: Change over time AND/OR Descent from a common ancestor.

5. Fossils show how species have evolved over time with many examples of intermediate stages • Fossils show: • the evolution of whales from land mammals • the evolution of land animals from fish • the evolution of mammals from reptiles • the evolution of humans from apelike ancestors • and the evolution of birds from dinosaurs

11. The fossil record is incomplete but there are thousands of fossils that support the theory of evolution.

12. Comparative anatomy shows how species evolved from a previous ancestor. • Homologous structures are made of the same basic parts but have evolved for very different functions. The wing of a bird, the front leg of a human, and the flipper of a whale all have the same bones but evolved from a common ancestor to do different things.

14. Comparative anatomy shows how species evolved from a previous ancestor. • Vestigial structures are structures that had a function in an ancestor but are now reduced and have no function. Wisdom teeth in humans are vestigial structures. Whales and some snakes still have the hind legs and hipbones used by their ancestors but not needed or used by them.

16. Comparative embryology shows that the early stages of embryos from very different organisms are often very similar. • Embryonic tissue goes through the same stages of development in early stage embryos. Early vertebrate embryos (including humans) all have tails. Early dolphin embryos have four legs.

19. Patterns in the distribution of living and fossil organisms tell us how modern organisms evolved from common ancestors. • Closely related organisms may look very different from each other if they evolved under different conditions like the finches and tortoises in the Galapagos and the honeycreepers in Hawaii.

23. The universal genetic code and homologous molecules provide evidence of descent from common ancestors. • The genetic code is the same for all organisms. The DNA codon TAC always codes for the amino acid methionine. • A gene taken from one organism (like a spider) and inserted into a goat will make the goat’s cells produce the spider protein.

24. The universal genetic code and homologous molecules provide evidence of descent from common ancestors. • Many basic development genes including the genes controlling production of legs and eyes in embryos are the same in insects, fish, and humans. • Many proteins are found in all living cells. Cytochrome c is a protein is a protein used in cellular respiration and is found in all eukaryotic cells. • Rhodopsin is a light detecting protein and is found in cells ranging from bacteria to the human eye.

25. Direct Observation of Evolutionary Change • Evolutionary change has been observed in: • Wild populations of guppies, birds, insects, and mammals. • It has also been observed in the laboratory in bacteria, fish, and insects.

26. SC.912.L.15.13 Describe the conditions required for natural selection, including overproduction of offspring, inherited variation, and the struggle to survive, which result in differential reproductive success. • All organisms produce more offspring than the environment can support. Giant puffballs can produce trillions of spores. A female sea urchin produces millions of eggs. Female fruit flies produce roughly 200 eggs. • Environmental resources are limited. The environment can’t support unlimited numbers of offspring. • This leads to competition for resources and a struggle for survival.

27. Genetic variation exists in organisms. Some variations are better than others. • Those organisms with the better combination of favorable adaptations survive better and produce more offspring. They pass their favorable genes on to their offspring. Organisms with less favorable traits do not survive and do not pass on their genes to offspring so those variations die out. • This is called differential reproduction.

28. Favorable variations spread throughout a population, changing the population. • This change is evolution by natural selection.

29. SC.912.L.15.15 Describe how mutation and genetic recombination increase genetic variation. • Mutations (changes in the DNA code) are the source of some variation in living organisms because they introduce new alleles into the gene pool.

30. SC.912.L.15.15 Describe how mutation and genetic recombination increase genetic variation. • Recombination is the production of new combinations of alleles by mixing alleles in new ways. • In sexually reproducing organisms the biggest source of variation is genetic recombination through meiosis and fertilization

31. SC.912.L.15.15 Describe how mutation and genetic recombination increase genetic variation. • Recombination occurs by: • Crossing over in Prophase I • Independent assortment in Metaphase I and Anaphase I • Fertilization

32. Discuss mechanisms of evolutionary change other than natural selection such as genetic drift and gene flow. • Genetic drift is the random change in the frequency of alleles in a population. It usually occurs in small populations. • Example – 99% of all Maya in Mexico and Inca in the Andes mountains have type O blood because the small groups of humans who migrated there had O blood

33. Gene flow is immigration into or emigration out of an area. Alleles will be lost when individuals enter or leave. • Example – The frequency of red hair and freckles rose sharply in New York and Boston in the 1850s due to the Irish immigration.

34. SC.912.L.15.4 Discuss how and why organisms are hierarchically classified and based on evolutionary relationships. • The goal of any classification system is to organize living things into groups that have biological meaning.

35. We classify organisms: • For easy reference and identification • To show relationships between organisms • To trace the origins of organisms

36. Classification is based on phylogeny, the evolutionary history of organisms.

37. The Linnaean System • Kingdom King Animalia • Phylum Phillip Chordata • Class Came Mammalia • Order Over Primate • Family For Hominida • Genus Great Homo • Species Spaghetti sapiens

38. The last two categories in the Linnaean system form an organism’s binomial scientific name. • The genus is capitalized and is a noun • The species is lower case and is an adjective • Scientific names are underlined or italicized. • Gammaracanthuskytodermagammarus loricatobaicalensis • Gammaracanthuskytodermagammarus loricatobaicalensis

39. Linnaeus used physical characteristics to classify. • Modern scientists use evolutionary relationships. • All the organisms in one group are descended from the same common ancestor.

40. Cladistics • All the organisms descended from a the same common ancestor are a clade. • Cladograms are diagrams that show how evolutionary lines or lineages branched off from a common ancestor. • Branching points are called nodes. A node is the last point at which two branches shared a common ancestor. • Nodes are defined by DERIVED CHARACTERS, characteristics that arose in the most recent shared common ancestor.

42. SC.912.L.15.6 Discuss distinguishing characteristics of the domains and kingdoms of organisms. • DOMAIN ARCHAEA • Single-celled • Prokaryotic • Live in extreme environmental conditions like high temperature, very low pH or no Oxygen. • Corresponds to Kingdom Archaebacteria

43. SC.912.L.15.6 Discuss distinguishing characteristics of the domains and kingdoms of organisms. • Domain Bacteria • Single-celled • Prokaryotic • Rigid cell walls • Corresponds to the Kingdom Eubacteria • Most of the bacteria you know and love fall into this domain

44. SC.912.L.15.6 Discuss distinguishing characteristics of the domains and kingdoms of organisms. • Domain Eukarya • Cells contain a nucleus • Consists of the other four kingdoms • Kingdom Animalia • Multicellular, heterotrophic, do NOT have cell walls and are capable of movement • Kingdom Plantae • Multicelluar, autotrophic, cell walls made of cellulose • Kingdom Fungi • Heterotrophic, cell walls made of chitin. Secrete digestive enzymes into their food and absorb digested nutrients • Kingdom Protista • Everything else

45. SC.912.L.15.8 Identify basic trends in hominid evolution from early ancestors six million years ago to modern humans, including brain size, jaw size, language, and manufacture of tools. • 6 Million years ago the lineage that led to humans split from the lineage that led to chimpanzees • Supported by both fossil and DNA evidence

46. During that six million years • Brain size quadrupled (grew 4X) • Jaw size and tooth size decreased as diet changed. Human jaws do not stick out like ape jaws do • Humans evolved language, allowing greater range of communications. • Homo habilis is the earliest KNOWN tool maker (2 million years ago). As genus Homo evolved a larger brain tools became more sophisticated. • Language and culture allowed tool making skills to be passed down.

47. SC.912.L.14.5 Explain the evidence supporting the scientific theory of the origin of eukaryotic cells (ENDOSYMBIOSIS). • Endosymbiotic theory – Eukaryotic cells evolved when a prokaryotic cell capable of aerobic respiration was engulfed by a larger prokaryotic cell and not digested • The smaller cell became the mitochondrion and the larger cell around it is the ancestor of all modern eukaryotic cells. • Chloroplasts are the result of one of the eukaryotic cells engulfing a photosynthetic bacteria and not digesting it.

48. Mitochondria and chloroplasts: • Contain DNA in a single, circular chromosome just like bacteria cells • Have “naked” DNA without attached proteins just like bacteria cells • Reproduce by binary fission just like bacteria cells

50. SC.912.L.15.8 Describe the scientific explanations of the origin of life on Earth. • Early Earth’s atmosphere was very different from the atmosphere today. • Little or no molecular oxygen • Made mostly of carbon dioxide, water vapor, nitrogen and some hydrogen sulfide.