section 2: evidence of evolution
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Section 2: Evidence of Evolution. Evidence of Evolution. Fossils. FORMS OF EVIDENCE. Similar body structures Patterns of early development DNA sequences Fossils. Comparative anatomy : The comparison of the structures of different organisms. - PowerPoint PPT PresentationTRANSCRIPT
Evidence of EvolutionEvidence
of Evolution
Similar body structures DNA and proteins
Comparative anatomy
Patterns in early development
Homologous structure
All vertebrates have a tail and rows
of slits in their throats.
Similar DNA mightMean that they
Evolved from the Same acestor
1.Molds and casts2.Petrified fossils3.Trace fossils4preserved remains
Fossils
FORMS OF EVIDENCE
1. Similar body structures2. Patterns of early development3. DNA sequences4. Fossils
Body structures
Comparative anatomy: The comparison of the structures of different organisms.
Homologous structures: Body parts that are structurally similar in related species.
Early Development
In early development, all vertebrates have a tail and tiny slits in their throats.
Learning from Fossils
The fossil record provides evidence about the history of life and past environments on Earth.
Scientists use fossils to study the rate at which evolution has occurred.
Past environments
Fossils can show how an environment has changed: EX. Coal in Antarctica – coal can only form from the remains of plants that grow in warm regions. (hmmm….)
Gradualism
Scientists are not sure how rapidly species change.
Gradualism proposes that evolution occurs.. but it happens steadily – tiny changes in a species gradually add up to major changes over long periods of time.
Fossil record show sudden change (lack of intermediate forms) – incomplete fossil record?