1 Evolution, Biodiversity, and Community Processes Dr. E

Evolution – What Next? Evolution – What Next? 2

3 What types of Life exist on the Earth?

4 Types of Organisms Prokaryotic Kingdom: single- celled organisms containing no internal structures surrounded by membranes (therefore there is no nucleus)Prokaryotic Kingdom: single- celled organisms containing no internal structures surrounded by membranes (therefore there is no nucleus) –Monera – bacteria and cyanobacteria

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6 Aerobic bacteria Ancient Prokaryotes Ancient Anaerobic Prokaryote Primitive Aerobic Eukaryote Primitive Photosynthetic Eukaryote Chloroplast Photosynthetic bacteria Nuclear envelope evolving Mitochondrion Plants and plantlike protists Animals, fungi, and non-plantlike protists Endosymbiotic Theory

7 Types of Organisms Eukaryotic Kingdoms: all organisms consisting of cells which contain membrane-bound nucleiEukaryotic Kingdoms: all organisms consisting of cells which contain membrane-bound nuclei –Protista - mostly one-celled organisms – have characteristics of all three other Eukaryote Kingdoms –Fungi - organisms which decompose stuff –Plantae - organisms which use photosynthesis to make their own food Annuals complete life cycle in one seasonAnnuals complete life cycle in one season Perennials live for more than one seasonPerennials live for more than one season –Animalia - organisms which must get organic compounds from food they eat - most are able to move Invertebrates – no backboneInvertebrates – no backbone Vertebrates – Fish, Amphibians, Reptiles, Birds and MammalsVertebrates – Fish, Amphibians, Reptiles, Birds and Mammals

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9 Naming Species

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12 EVOLUTION is Gradual Change

13 How did Life Originate? Or Chemical Evolution

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24 Biological Evolution

25 Evolutionary Bush One life-form splits into two and those branches split (independently) to make more. Time   Phenotypic ‘distance’ 

26 Evolutionary Bush -- thousands of earlier and later branches.

27 At any given moment (e.g. the ‘present’), all we see is current diversity… all extinct forms are gone (99.9%) Time 

28 Charles Darwin British naturalist Proposed the idea of evolution by natural selection Collected clear evidence to support his ideas

29 Darwin’s finches 13 species of finches in the Galápagos Islands Was puzzling since only 1 species of this bird on the mainland of South America, 600 miles to the east, where they had all presumably originated

30 Darwin’s finches Differences in beaks –associated with eating different foods –adaptations to the foods available on their home islands Darwin concluded that when the original South American finches reached the islands, they adapted to available food in different environments

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32 What did Darwin say? Organisms reproduce more than the environment can support –some offspring survive –some offspring don’t survive –competition for food for mates for nesting spots to get away from predators

33 Survival of the fittest Who is the fittest? –traits fit the environment –the environment can change, so who is fit can change Peppered moth

34 Adaptive Radiation When one species splits into many species to fill open habitats. –Darwin’s finches

35Speciation One species can evolve into two or more species 2 step process –Geographical isolation –Reproductive isolation When a group becomes geographically isolated over time it will become reproductively isolated = new species formed.

36 Geographic isolation When a population becomes divided by a natural barrier. Mountains, river, body of water, landslides Groups can’t interbreed or intermix Become adapted to a different environment Harris’s antelope squirrel inhabits the canyon’s south rim (L). Just a few miles away on the north rim (R) lives the closely related white-tailed antelope squirrel Ammospermophilus spp

37 Reproductive Isolation Differences in isolated groups become so great, they can no longer interbreed –Physical changes –Behavioral changes –Biochemical changes

38 Stephen Jay Gould ( ) Harvard paleontologist & evolutionary biologist –punctuated equilibrium –prolific author popularized evolutionary thought

39 Punctuated Equilibrium

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41 Speciation Evolution of new species

42 Four causes of evolutionary change: 1.Mutation: fundamental origin of all genetic (DNA) change.

43 Four causes of evolutionary change: 1.Mutation: fundamental genetic shifts. 2.Genetic Drift: isolated populations accumulate different mutations over time. 1.Mutation: fundamental genetic shifts. 2.Genetic Drift: isolated populations accumulate different mutations over time. In a continuous population, genetic novelty can spread locally.

44 Four causes of evolutionary change: But in discontinuous populations, gene flow is blocked.

45 Four causes of evolutionary change 1. Mutation: fundamental genetic shifts. 2. Genetic Drift: isolation  accumulate mutations 3. Founder Effect: sampling bias during immigration. When a new population is formed, its genetic composition depends largely on the gene frequencies within the group of first settlers. 1. Mutation: fundamental genetic shifts. 2. Genetic Drift: isolation  accumulate mutations 3. Founder Effect: sampling bias during immigration. When a new population is formed, its genetic composition depends largely on the gene frequencies within the group of first settlers.

46 Founder Effect.-- Human example: your tribe had to live near the Bering land bridge…

47 Founder Effect.-- …to invade & settle the ‘New World’!

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49 Four causes of evolutionary change: 1.Mutation: fundamental genetic shifts. 2.Genetic Drift: isolation  accumulation of mutations 3.Founder Effect: immigrant sampling bias. 4.Natural Selection: differential reproduction of individuals in the same population based on genetic differences among them. 1.Mutation: fundamental genetic shifts. 2.Genetic Drift: isolation  accumulation of mutations 3.Founder Effect: immigrant sampling bias. 4.Natural Selection: differential reproduction of individuals in the same population based on genetic differences among them.

50 Four causes of evolutionary change: 1.Mutation: fundamental genetic shifts. 2.Genetic Drift: isolation  accumulation of mutations 3.Founder Effect: immigrant sampling bias. 4.Natural Selection: reproductive race These 4 interact synergistically 1.Mutation: fundamental genetic shifts. 2.Genetic Drift: isolation  accumulation of mutations 3.Founder Effect: immigrant sampling bias. 4.Natural Selection: reproductive race These 4 interact synergistically

51 Evidence of Evolution

1. Biogeography: Geographical distribution of species

2. Fossil Record: Fossils and the order in which they appear in layers of sedimentary rock (strongest evidence)

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55 Half-life for a given radioisotope is the time for half the radioactive nuclei in any sample to undergo radioactive decay

3. Taxonomy: Classification of life forms.

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Mammal Family Tree Mammal Family Tree 58

4. Homologous Structures: Structures that are similar because of common ancestry (comparative anatomy) TurtleAlligatorBirdMammals Typical primitive fish

5. Comparative Embryology: 5. Comparative Embryology: Study of structures that appear during embryonic development

6. Molecular Biology: DNA and proteins (amino acids)

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