1. APES C HAPTER 5 Evolution and Biodiversity: Origins, Niches, and Adaptation

2. O RIGINS OF L IFE -2 PHASES : Evolution of the organic molecules, biopolymers, and systems of chemical reactions needed to from the first protocells Lasted approx. 1 billion years Evolution of single- celled organisms (prokaryotes and then eukaryotes) and then multi-cellular organisms Took approx. 3.7-3.8 billion years. Chemical evolutionBiological evolution

3. C HEMICAL EVOLUTION 4.6-4.7 billion years ago—cosmic dust cloud condensed to from earth. 4.4 billion years ago—atmosphere was formed— contained NO oxygen. Energy available—lightening, heat from volcanoes, and UV radiation. Stanley Miller and Harold Urey provided experimental support the inorganic molecules could combine to form simple organic molecules under the conditions of the primitive Earth. Organic molecules may have formed membrane – bound protocells.

4. B IOLOGICAL E VOLUTION Protocells evolved into single-celled prokaryotes 2.3-2.5 billion years ago, evolution of photosynthetic prokaryotes started producing O 2 1.2 billion years ago the first eukaryotic cells formed. 400-500 million years: first plants on land, then mammals, then man.

5. O RIGINS OF L IFE Fig. 5-2 p. 96; Refer to Fig. 5-4 p. 98

6. H OW DO WE KNOW ORGANISMS LIVED IN THE PAST ? Fossils Relative dating—superposition and index fossils Absolute dating—radioactive decay rate (half life)

8. E VOLUTION AND A DAPTION Evolution—the change in a population’s genetic makeup through successive generations. Individuals do not evolve, only populations evolve.

10. Fish Salamander Turtle Chick Hog Calf Rabbit Human

11. Microevolution—describes the small genetic changes that occur in a population. Macroevolution—describes the long-term, large-scale, evolutionary changes among groups of species. 1. speciation (new species formed from ancestral species) 2. species lost through extinction.

12. M ACROEVOLUTION

13. H OW M ICROEVOLUTION W ORKS There must be a change in the Gene Pool (sum total of all genes possessed by the individuals of a population). 1. mutations—only changes in reproductive cells are passed on to offspring Random and unpredictable Most are harmful

14. M ICROEVOLUTION

15. N ATURAL S ELECTION Three conditions necessary for evolution by natural selection to occur. 1. natural variability 2. heritable trait 3. differential reproduction-greater chance for one form to reproduce. Three types of natural selection 1. directional 2. stabilizing 3. diversifying

17. D ARWIN ’ S N ATURAL S ELECTION

18. Directional Natural Selection Natural selection Proportion of light-colored snails in population increases Number of individuals Snail coloration best adapted to conditions Average Coloration of snails New averagePrevious average Number of individuals Coloration of snails Average shifts F IGURE 5-6 (1) P AGE 102

20. Coloration of snails Snails with extreme coloration are eliminated Number of individuals Stabilizing Natural Selection Average remains the same, but the number of individuals with intermediate coloration increases Natural selection Coloration of snails Light snails eliminated Dark snails eliminated Number of individuals F IGURE 5-6 (2) P AGE 102

22. Number of individuals with light and dark coloration increases, and the number with intermediate coloration decreases Coloration of snails Number of individuals Snails with light and dark colors dominate Diversifying Natural Selection Coloration of snails Number of individuals Light coloration is favored Dark coloration is favored Intermediate-colored snails are selected against Natural selection F IGURE 5-6 (3) P AGE 102

24. C OEVOLUTION Interaction between species that results in microevolution in each of their populations. Ex: flowers and pollinators predators and prey

25. The parasites have often evolved eggs that closely mimic those of the host, and young with characteristics that encourage the hosts to feed them. In response, some hosts have developed the ability to discriminate between their own and parasitic eggs, and various methods of destroying the latter.

26. H OW M ACROEVOLUTION W ORKS Evolution that takes place over an extremely long time involving groups of species. Speciation—forming a new species Geographic isolation  reproductive isolation  speciation

27. M ACROEVOLUTION How do species become extinct? When environmental conditions change, a species may cease to exist if it cannot adapt. Background extinction—disappearance of species’ at a low gradual rate. Mass extinction—abrupt rise in extinction rate above the background level catastrophic and worldwide where large numbers of species are eliminated. We have had five major extinctions with the last being 65 million years ago (at the end of the mesozoic era). A sixth mass extinction is currently happening and caused by humans.

28. M ACROEVOLUTION Adaptive radiation—period of recovery, rapid divergent evolution leading to speciation, following mass extinctions. There are two theories about how rapidly macroevolution occurs: 1. gradualist model of evolution 2. punctuated equilibrium hypothesis—gradual evolution interrupted periodically by rapid speciation.

29. G RADUALISM VS. P UNCTUATED E QUILIBRIUM

30. G RADUALISM

31. P UNCTUATED E QUILIBRIUM

32. E COLOGICAL N ICHES AND A DAPTATION Ecological Niche—the species’ way of life or role in an ecosystem. Includes: Range of tolerance Type of resources it uses How it interacts with components of the ecosystem  Fundamental niche—full potential range of physical, chemical, and biological conditions under with an organism could survive.  Realized niche—the actual part of the fundamental niche occupied by the organism.

35. Species can have broad niches ( generalists : roaches, flies, coyotes, humans) while other have narrow niches ( specialists : spotted owls, giant pandas) Habitat—the physical location where a species lives.

36. C OMMON M ISCONCEPTIONS C ONCERNING E VOLUTION

37. E VOLUTION M ISCONCEPTIONS Misconception: “Survival of the Fittest” means survival of the strongest. Truth: To biologists, Fitness is a measure of reproductive success NOT strength. Misconception: Evolution involves some grand plan of nature in which organisms are becoming more complex/perfect with time. Truth: From a scientific standpoint, no plan or goal exists in the evolutionary process.

38. Plants begin invading land Evolution and expansion of life First fossil record of animals Plants invade the land Age of reptiles Age of mammals Insects and amphibians invade the land Modern humans (Homo sapiens) appear about 2 seconds before midnight Recorded human history begins 1/4 second before midnight Origin of life (3.6–3.8 billion years ago) noon midnight