Chapter 4: Organization of Life 4.2 Evolution. Evidence of Evolution Comparative Anatomy –Atavisms...
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Chapter 4: Organization of Life 4.2 Evolution
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Transcript of Chapter 4: Organization of Life 4.2 Evolution. Evidence of Evolution Comparative Anatomy –Atavisms...
Chapter 4: Organization of Life
4.2 Evolution
Evidence of Evolution• Comparative Anatomy
– Atavisms• A recurrence of a trait from ancestral origin
– Small tail in human babies– Legs in snakes
– Homologous Structures• A body part with similar structure and origin
– Forelimbs in mammals– Vestigial Structures
• A body part that has lost all or most of its function – Hind legs in whales– Appendix/wisdom teeth in humans
Evidence of Evolution• Physiology/Biochemistry
– DNA sequences are similar• Chimpanzees: 1.2% difference• Gorillas: 1.6% difference
– Embryonic development begins nearly identical across classes of vertebrates
• Distribution– Common animals found on different continents
• Monkeys: S & Central America/Africa/Asia• Observation
– Experimentation and artificial selection
Natural Selection• Proposed by Darwin in the Origin of Species• Sequence of Ideas:
– 1. Overpopulation• 1-4 Polar Bear Cubs; Average: 2
– 2. Competition• Arctic is cold and void of food/water
– 3. Survival of the Fittest• 43% Survival rate in Beaufort Sea
– 4. Reproduction• Survivors reproduce
– 5. Speciation• Further reproduction promotes “fit” organisms
Adaptations• An anatomical, physiological, or behavioral change that
improves the ability to survive– Anatomical
• Physical features of an organism– Size, Color, Jaw structure
– Physiological• Specialized body functions
– Digestion, Reproduction, Venom– Behavioral
• Inherited or learned actions– Migration, Mating, Predator Fear
– Many adaptations are interconnected
Convergent Evolution• Convergent Evolution
– Organisms of uncommon ancestry develop similar traits• Wings: Birds, mammals, fish, insects• Fins: Fish and mammals• Long, sticky tongues: Anteaters, pangolins,
armadillos.• Echolocation: bats and whales
• Divergent Evolution– Organisms of common ancestry develop different traits
• Darwin’s Finches
Coevolution• Coevolution
– Change in the genetics of one organism in response to another• Flowers and Pollinators
– Hummingbirds & Flowers» Curved beak ideal for corolla» Vision is centered on red
– Long-nosed Bats and Saguaros• Evolutionary arms race
– Predator vs. Prey Speed– Venom vs. Anti-venom
Artificial Selection• Selective breeding of organisms by humans for
specific desirable characteristics– Domestic dogs are descendents of wolves– Broccoli, Brussels Sprouts, Cauliflower, Cabbage
are all engineered from wild mustard seed– All modern corn is genetically engineered– All wheat/grains are genetically engineered
Resistance• Ability of an organism to tolerate a chemical or disease-causing
agent– Studies indicate bacteria are becoming more resistant to
antibiotics over time• MRSA
– Highly resistant “Staph” infection• Strep is becoming more resistant over time
– Responsible for Pneumonia and Meningitis– Studies indicate that insects are becoming more resistant to
pesticides over time• House Flies are becoming resistant to DDT• DDT is also becoming limited in malaria prevention• English Rats can consume 5x rat poison of US rats before
showing signs of fatality• Potato Beetle is immune to >52 insecticides
Homework
• Page 109-111• 11, 13, 20, 21, 23, 24
