1. Chapter 4 4-1 origins of life.

2. Key Concepts Origins of life- Life started about 3.7 billion years ago. Origins of life- Life started about 3.7 billion years ago. Evolution and evolutionary processes: Micro (small genetic changes) and Macro (long-term, species wide changes) Evolution and evolutionary processes: Micro (small genetic changes) and Macro (long-term, species wide changes) Ecological niches: Species adapting to a specific role in their ecosystem. Ecological niches: Species adapting to a specific role in their ecosystem. Species formation: Unique adaptations of small populations. Species formation: Unique adaptations of small populations. Species extinction: a failure to adapt. Species extinction: a failure to adapt.

3. Fig. 4-3, p. 66 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) Biological Evolution of Life

4. Biological Evolution Evolution: Change in the genetic make-up of a population over time. Evolution: Change in the genetic make-up of a population over time. Theory of evolution: Life comes from life. All species descended from ancestral species. Theory of evolution: Life comes from life. All species descended from ancestral species. Microevolution: occurs on a genetic level. Mutations are either advantageous or deleterious. Microevolution: occurs on a genetic level. Mutations are either advantageous or deleterious. Macroevolution: Successive changes over generations of a population. Macroevolution: Successive changes over generations of a population.

5. Microevolution Gene pool: All the genes in an individual. Gene pool: All the genes in an individual. Genetic variability: Genetic diversity amongst a population. Allows for adaptation, key to population survival. Genetic variability: Genetic diversity amongst a population. Allows for adaptation, key to population survival. Mutations: Random changes in the structure of DNA. Can be advantageous or deleterious. Mutations: Random changes in the structure of DNA. Can be advantageous or deleterious. Mutagens: capable of changing DNA. Radiation, certain chemicals. Cigarettes… Mutagens: capable of changing DNA. Radiation, certain chemicals. Cigarettes… Natural selection: Certain populations having traits that allow them to be more successful than others. Natural selection: Certain populations having traits that allow them to be more successful than others.

6. Natural Selection Differential reproduction: Some species reproduce better than others (competitive). Differential reproduction: Some species reproduce better than others (competitive). Adaptation (adaptive trait): Heritable trait that allows an organism to survive and reproduce. Adaptation (adaptive trait): Heritable trait that allows an organism to survive and reproduce. Coevolution: Biological Arms Race. Species gaining a temporary genetic advantage over competitors. Coevolution: Biological Arms Race. Species gaining a temporary genetic advantage over competitors.

7. Ecological Niches and Adaptation Ecological niche: Species way of life or functional role in an ecosystem. Ecological niche: Species way of life or functional role in an ecosystem. Habitats: Physical location of a species. Habitats: Physical location of a species. Fundamental niche: Potential range of a species. Resources it could use. Fundamental niche: Potential range of a species. Resources it could use. Realized niche: What it does use. Realized niche: What it does use.

8. Broad and Narrow Niches and Limits of Adaptation Generalist species: broad niches. Variety of potential foods and habitats. Rats, roaches, coyotes, catfish. Generalist species: broad niches. Variety of potential foods and habitats. Rats, roaches, coyotes, catfish. Specialist species: Very adapted. Limited foods and niches. Pandas, red cockaded woodpeckers… Specialist species: Very adapted. Limited foods and niches. Pandas, red cockaded woodpeckers… Limits of adaptation: Gene pool, and reproduction speed. Limits of adaptation: Gene pool, and reproduction speed.

9. Fig. 4-4, p. 68 Niche separation Specialist species with a narrow niche Generalist species with a broad niche Niche breadth Region of niche overlap Niches of Specialist and Generalist Species Resource use Number of individuals

10. Specialized Feeding Niches for Birds Black skimmer seizes small fish at water surface Flamingo feeds on minute organisms in mud Scaup and other diving ducks feed on mollusks, crustaceans, and aquatic vegetation Brown pelican dives for fish, which it locates from the air Avocet sweeps bill through mud and surface water in search of small crustaceans, insects, and seeds Louisiana heron wades into water to seize small fish Oystercatcher feeds on clams, mussels, and other shellfish into which it pries its narrow beak Dowitcher probes deeply into mud in search of snails, marine worms, and small crustaceans Knot (a sandpiper) picks up worms and small crustaceans left by receding tide Herring gull is a tireless scavenger Ruddy turnstone searches under shells and pebbles for small invertebrates Piping plover feeds on insects and tiny crustaceans on sandy beaches Fig. 4-5, p. 68-69

11. Fig. 4-6, p. 70 Unknown finch ancestor Fruit and seed eaters Insect and nectar eaters Greater Koa-finch Kona Grosbeak Akiapolaau Maui Parrotbill Kuai Akialaoa Crested Honeycreeper Apapane Amakihi Evolutionary Divergence of Honeycreepers

12. Misconceptions of Evolution “Survival of the fittest”: Reproductive strength, not individual health. “Survival of the fittest”: Reproductive strength, not individual health. “Progress to perfection” More evolved does not mean better, in fact, the loss of traits often leads to extinction. “Progress to perfection” More evolved does not mean better, in fact, the loss of traits often leads to extinction.

13. Speciation What is speciation? What is speciation? -A new species arises when members of one population are isolated. -A new species arises when members of one population are isolated. Geographic isolation: members of one population become physically isolated from the other. Geographic isolation: members of one population become physically isolated from the other. Reproduction isolation: Members of the separated population can no longer interbreed with the original population. Reproduction isolation: Members of the separated population can no longer interbreed with the original population.

14. Fig. 4-7, p. 71 Spreads northward and southward and separates Arctic Fox Gray Fox Adapted to cold through heavier fur, short ears, short legs, short nose. White fur matches snow for camouflage. Adapted to heat through lightweight fur and long ears, legs, and nose, which give off more heat. Different environmental conditions lead to different selective pressures and evolution into two different species. Northern population Southern population Early fox population Geographic Isolation can Lead to Speciation

15. Factors Leading to Extinction Plate tectonics Plate tectonics Sinking/uplifting Sinking/uplifting Climatic changes over time Climatic changes over time Ice ages. Ice ages. Droughts Droughts Natural catastrophes Natural catastrophes Volcanos Volcanos Meteors Meteors Human impacts Human impacts Habitat degradation Habitat degradation Invasive species Invasive species

16. Extinctions Background extinctions Background extinctions Species disappearing a low rate, mainly by “Natural Causes”. 99.9% of all species. Species disappearing a low rate, mainly by “Natural Causes”. 99.9% of all species. Mass extinctions: Rise in extinction rates above the background level. Mass extinctions: Rise in extinction rates above the background level. Mass depletions: High rates, but not that high. Mass depletions: High rates, but not that high. Human impacts: During the 20 th century, extinction rates increased 100-1,000 times. Humans change the environment faster than species can adapt. Human impacts: During the 20 th century, extinction rates increased 100-1,000 times. Humans change the environment faster than species can adapt. Biodiversity = Speciation – Extinction. Biodiversity represents the planets raw genetic material for future evolution. Lack in biodiversity = inability to adapt. Biodiversity = Speciation – Extinction. Biodiversity represents the planets raw genetic material for future evolution. Lack in biodiversity = inability to adapt.

17. PANGAEA GONDWANALAND LAURASIA NORTH AMERICA ANTARTICA AUSTRALIA AFRICA EURASIA SOUTH AMERICA INDIA MADA GASCAR 225 million years ago135 million years ago 65 million years agoPresent Fig. 4-8, p. 72 “Continental Drift” (Plate Tectonics): The Breakup of Pangaea

18. Top 5 best mass extinctions of all time! Ordovician: 500 million years ago. 50% of animal families wiped out. Ordovician: 500 million years ago. 50% of animal families wiped out. Devonian: 30% of agnathan and placoderm fishes. Devonian: 30% of agnathan and placoderm fishes. Permian: 90% of all animal species. 95% of marine species. All trilobites. Permian: 90% of all animal species. 95% of marine species. All trilobites. Triassic: 35% of animal families, lots of reptiles. Triassic: 35% of animal families, lots of reptiles. Cretaceous: up to 80% of all animal species. Cretaceous: up to 80% of all animal species.

19. Mass Extinctions of the Earth’s Past Fig. 4-9, p. 73

20. Fig. 4-10, p. 74 Terrestrial organisms Marine organisms Quaternary Tertiary Cretaceous Jurassic Triassic Permian Carboniferous Devonian Silurian Ordovician Cambrian Pre-cambrain 1.80651452052502903554104405005453500 0 1600 1200 800 400 Number of families Millions of years ago Changes in Biodiversity over Geologic Time