Evidence for evolution powerpointPresentation Transcript
Evolution: Evidence SC.912.L.15.1 Explain how the scientific theory of evolution is supported by the fossil record, comparative anatomy, comparative embryology, biogeography, molecular biology, and observed evolutionary change
Types of Evidence we will be covering
Fossils support the idea of evolutionary progression.
By looking at fossils Paleontologists/zoologists can:
Identify extinct animal species
Follow the path of evolution through different stages of development
Evolution of the Whale
Key Points of the Fossil Record
Provides evidence of evolution from one species to another
Shows ancestral intermediates
Only hard tissue is preserves
FLASH CARD ALERT:
TRANSITIONAL FOSSIL: fossils that show transitions in evolution.
Transitional fossils are RARE findings
Small proportion of organisms become fossils
Many fossils represent dead evolutionary branches
Support: Comparative Anatomy
Homologous Structures: Similar features found in different species that are derived (come from) a common ancestor
Ex. Tetrapod limbs, fur, lungs
Bone formation: developmental and evolutionary similarities
Evidence of intermediates
FLASH CARD ALERT:
Analogous Structures: a trait or an organ that appears similar in two unrelated organisms
Happens because of convergent evolution:
FLASHCARD ALERT: CONVERGENT EVOLUTION: Species evolve in similar environments and have similar environmental stressors/survival factors
Vestigial Structures : characteristics found in existing species that have no known function
Provide evidence of common ancestry
As species evolve their structures change
Two things will happen
Species will adapt the organ/structure to a new use
The organ or structure will no longer have a use
Whale pelvis/snake feet.
Useless for Flying but excellent for swimming
Stubs on pythons, boas, and other snakes
Useless Vestigial structures are BETTER sources of evidence for evolution
What is the major difference between analogous and homologous structures?
What structure is the best evidence of evolution: analogous, homologous or vestigial
What kind of tissue/part of an animal is preserved in fossils?
What type of fossils are paleontologists most interested in?
Why are they hard to find?
Incredible similarities in embryos of different species provides evidence of common ancestor
Patterns of embryo development are also important.
Zoologists seek to understand how very closely related species ended up in completely different parts of the world
Support for Pangaea
Key Point of Biogeography
Seeks to answer the question: how/why different but similar species exist in similar yet separate parts of the world
Can be explained by geological changes, migrations, convergent evolution
Support ideas of common ancestor and Pangaea
What are the five steps of evolution?
How does the environment affect the process of evolution?
Adaptations help the organism:
The three types of structures that support evolution are:
Paleontologists are excited to find what kind of fossil and why?