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Review Chapter 11
Evolution
Evolution: change of population of organisms over generations
Explain Darwin’s theory of Evolution
 Voyage around the world and many discoveries on Galapago’s Islands

Natural selection: organisms best suited to their environment reproduce more
successfully than other organisms

Galapagos’s finches: each had a different beak shape that allowed them to eat a
certain food that was on that island: all descended from one species

Galapagos’s tortoises: different shell shape on different islands
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Darwin waited over 20 years to publish his findings
Explain Darwin’s Two Theories
1. Descent with modification
 All species descended from a few original types of life
 Species must be able to change over time
2. Natural selection: process by which individuals that are better adapted to their
environment survive and reproduce more successfully than less well adapted individuals
Four main parts of natural selection
1. Overproduction: more offspring can be produced than can survive to
maturity
2.
Genetic variation: within a population, individuals have different traits and
the traits can be inherited
3.
Struggle to survive: compete for food and shelter
4.
Differential reproduction: organisms with the best adaptations are most
likely to survive and reproduce
Define
 Adaptation: trait that makes an individual successful in its environment

Fitness: organisms ability to reproduce and pass on it traits
Ideas of Darwin’s Time
1.
2.
Species did not change
Earth was only a few thousands year old
3.
Lamarck’s idea: acquired trait: organisms could acquire traits during their
lifetimes as a result of experience or behavior and then pass on those traits to
offspring (not correct)
Types of fossils and where fossils are found
Types
 Bones
 Shells
 Footprints
 Imprints
Oldest fossils found in lowest level (strata) of rock
Evidence of evolution
1.
2.
3.
4.
5.
6.
Fossils
Homologous and analogous structures
Biogeography
Vestigial structures
Similarities in embryology
Similarities in biological molecules (DNA)
Homologous structure: similar features that originated in a shared ancestor (limb bones)
Analogous: serve identical functions and look alike but evolved independently (wings)
Biogeography: study of the location of organisms around the world
Vestigial: features that were useful to an ancestor but they are not useful to the modern
organism (appendix)
Phylogeny: relationships by ancestry among groups of organism (family tree)
Types of evolution
1. Coevolution: two or more species have evolved adaptations to each other
Example: predator and prey
2. Convergent evolution: process by which different species evolve similar traits
even though they had different ancestor
Example: sharks and dolphins have similar body shape
3. Divergent evolution: descendants of a single ancestor become more and more
different due to different environments
Example: Galapagos’s finches
4. Artificial selection: human breeder chooses individuals that will parent the next
generation
Example: Horses, dogs, crops