Causes of Diversity and Evolution of Life on Earth Charles Darwin Alfred Russell Wallace.
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Transcript of Causes of Diversity and Evolution of Life on Earth Charles Darwin Alfred Russell Wallace.
Causes of Diversity and Evolution of Life on EarthCauses of Diversity and
Evolution of Life on Earth
Charles Darwin Alfred Russell Wallace
Causes for Diversity of LifeCauses for Diversity of Life
1. All populations have the potential to increase in size2. Many populations retain a constant size
• Many individuals die young3. Individuals in a population differ in their abilities
• Some of these abilities affect survival4. Best adapted individuals are most likely to survive and
produce offspring (Natural Selection)• “Abilities” are passed on to offspring (Genetics)
5. Over time the “abilities” of the population shift to include advantageous traits (Evolution)
1. All populations have the potential to increase in size2. Many populations retain a constant size
• Many individuals die young3. Individuals in a population differ in their abilities
• Some of these abilities affect survival4. Best adapted individuals are most likely to survive and
produce offspring (Natural Selection)• “Abilities” are passed on to offspring (Genetics)
5. Over time the “abilities” of the population shift to include advantageous traits (Evolution)
Note:
Natural Selection Affects Individuals
Evolution Affects Populations
Note:
Natural Selection Affects Individuals
Evolution Affects Populations
Net Result:
Populations change with time to become better
adapted to their environment (Evolution)
Net Result:
Populations change with time to become better
adapted to their environment (Evolution)
Example: Microbe Resistance
Example: Microbe Resistance
Apply Antibiotic
Survivor’s with Resistance Reproduce
Why is there Genetic Variation?Why is there Genetic Variation?(How do will fill the Gene Pool?)
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How does it Work?How does it Work?Variation is a result of (1) Mutations and (2) Sex
Errors occur in DNA Replication
On average 1:10,000-100,000genes per individual per generation
Errors increased by exposure to radiation, etc.
Most Mutations are bad or at least neutral
What is “good” depends on environmental conditions
Evidence for EvolutionEvidence for Evolution
Evidence for Evolution: Fossils
Evidence for Evolution: Fossils
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Evidence for Evolution: Analogous Structures
Evidence for Evolution: Analogous Structures
Evidence for Evolution:Homologous StructuresEvidence for Evolution:Homologous Structures
Evidence for Evolution:Embryology
Evidence for Evolution:Embryology
Evidence for Evolution:
Biochemistry of Life
Evidence for Evolution:
Biochemistry of Life
Evidence for Evolution:
Gene Sequencing
Evidence for Evolution:
Gene Sequencing
Evidence for Evolution:Artificial Selection
Evidence for Evolution:Artificial Selection
Evidence for Evolution:Artificial Selection
Evidence for Evolution:Artificial Selection
Evidence for Evolution:Modern Examples
Evidence for Evolution:Modern Examples
Some InterestingEffects of EvolutionSome Interesting
Effects of Evolution
Evolution & PsuedoextinctionEvolution & Psuedoextinction
Species A Species B
Through time Species A evolves into Species B
In effect, Species A goes extinct
ExtinctionExtinction
Species A
Sometimes a species cannot adapt fast enough to environmental change or competition
“Background Extinction”:Species Lifespan
“Background Extinction”:Species Lifespan
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Mass ExtinctionMass Extinction
Evolution & SpeciationEvolution & Speciation
Species A
Species B
Species C
Species A is separated into 2 isolated populations, each affected by different environmental conditions
In effect, Species A goes Extinct
Speciation ofKaibab & Abert Squirrels
Speciation ofKaibab & Abert Squirrels
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Speciation of Hawaiian
Honeycreepers
Speciation of Hawaiian
Honeycreepers
Diversity IncreasesDiversity Increases
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Classification:Based on
Evolutionary Relationships
Classification:Based on
Evolutionary Relationships
Species
Genus
Family
Convergent EvolutionConvergent Evolution
Coevolution:Plants and Pollinators
Coevolution:Plants and Pollinators
Coevolution:Predator/PreyCoevolution:Predator/Prey
Conclusions:
Biodiversity, genetic diversity, and community complexity are all the result of 100’s million of
years of evolution
Conclusions:
Biodiversity, genetic diversity, and community complexity are all the result of 100’s million of
years of evolution