Download LECTURE 9 Evolution, Speciation, and Extinction I

LECTURE 9
Evolution, Speciation, and Extinction
I. Evolution and Speciation
A. Some Basic Genetics
B. Natural Selection
C. Isolation and Speciation
II. Geography and Evolution
III. Extinction
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I. Evolution and Speciation
Evolution: Genetically controlled changes in physiology,
anatomy, and behavior that occur to a species over time.
Speciation: The development of two or more genetially
differentiable species from a single common ancsetor.
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I. Evolution and Speciation
DNA
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I. Evolution and Speciation
Alleles and polymorphism.
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I. Evolution and Speciation
Natural Selection: The process by which the genes for
genetically controlled traits become more common in a
population over time because individuals with those traits
are reproductively more successful than other individuals.
Charles Darwin
(1809-1882)
Alfred Russel Wallace
(1823-1913)
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I. Evolution and Speciation
Isolation and Speciation:
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LECTURE 9
I. Evolution and Speciation
Isolation and Speciation:
LECTURE 9
I. Evolution and Speciation
Isolation and Speciation:
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I. Evolution and Speciation
Isolation and Speciation:
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I. Evolution and Speciation
Genetic Drift: Stochastic changes in the genetic
composition of a population that occur over time as
new genes arise via mutation and other genes are
lost through chance processes. (ex. Bottleneck and
Founder Effect)
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II. Geography and Evolution
Founder Effect:
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II. Geography and Evolution
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II. Geography and Evolution
Adaptive Radiation: The development of many species
from a single founding species.
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II. Geography and Evolution
Convergent Evolution:
The development of
similar morphological or
physiological traits in
unrelated species living
in geographically
separated regions that
have similar
environments.
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II. Geography and Evolution
Coevolution: Two unrelated species evolve traits
that are tied to their interactions.
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II. Extinction
Extinction: The loss of
all individuals in the
population of a given
species, genus, family, or
order.
Ex. Local Extinction
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II. Extinction
Ex. Global Extinction
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II. Extinction
Trophic Cascade
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Mass Extinctions:
II. Extinction
Extinction of megafauna
Extinction of marine mammals
Extinction of dinosaurs
Extinction of 50-90% plants and animals
Extinction of 50% animals
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II. Extinction
What factors contribute to extinction?
• Complex behavioral, physiological, or
morphological adaptations
•
Species that are large in size
•
Predators
•
Small population size
•
Confined to a small geographic area
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