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Warm Up 9/18/08. What conclusions can you make based on your observations of your geological timeline?. Ch 15.1 Notes. Natural Selection & Evidence for Evolution. Charles Darwin. English Scientist (1809-1892) Used fossils to shape ideas about evolution - PowerPoint PPT Presentation
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What conclusions can you make based on your observations of your geological timeline?
Warm Up Warm Up 9/18/089/18/08
Ch 15.1 Notes
Natural Selection & Evidence for
Evolution
Charles DarwinCharles DarwinEnglish Scientist (1809-1892)
Used fossils to shape ideas about evolution
Suspected species change or evolve over time
Darwin on HMS Beagle•Took many years to develop theory of evolution
•Ships naturalist studies and collects specimens
•Becomes curious about relationships
•These studies provide foundation for his theory
Darwin in Galapagos Islands
•Group of small islands near equator
•Species were unique to island but similar to species elsewhere
•These observations led him to believe species change over time
Darwin Continues His Studies
Works for another 20 years to refine his explanation
English Economist Thomas Malthus proposes idea about human population
Species produce large number of Offspring
Creates competition for food space an finding mates
Natural Selection
Mechanism for change in populationsOrganisms with favorable variations survive and reproduceThese variations are passed on to next generation
Interpretation of Evidence
Volumes of data collectedSubject to interpretationProcesses are difficult for humans to observeGenetics has added more data
Part Two
Adaptations: Evidence for Evolution
Structural Adaptations
According to Darwin’s theory species adaptations occur over many generations
Study the Mole–rat: Lives in ground and has many adaptations , is blind, has big claws, large teeth
MIMICRY is a structural adaptation that enables one species to look like another
CAMOUFLAGE adaptations that allow species to blend in environment
MIMICRY
Camouflage
Physiological Adaptations
Most structural adaptations develop over a millions of years
Physiological adaptations evolve quicker
Physiological adaptations are changes in organisms metabolic processes
Example: antibiotics and pesticides
Fossils
Provides record of early life Ancestors of whales where dog like
creatures The fossil record is incomplete Like putting together a jigsaw puzzle
ANATOMY Look at forelimbs of whale, crocodile, and bird Evidence that animals evolved from common
ancestor Homologous Structures: structural features with
common evolutionary origin Analogous Structure: do not have common
evolutionary origin but have similar function Vestigial Structure: body structure in modern day
organism that no longer serves it original purpose
Homologous Structures
Analogous Structures
Vestigial Structures
Embryology
Easy to distinguish between adult organisms but can you distinguish between there organisms?
It is the shared features in the young embryos that suggest evolution from an distant common ancestor
Biochemistry
Provides strong evidence for evolutionNearly all organism share DNA, ATP and many enzymesOrganisms that are biochemically similar have fewer differences in their amino acid squences