7.6,7,8: Evidence Of Evolution And Comparative Morphology Flashcards
Overwhelming evidence supports the theory of evolution. What are the three primary sources of evidence?
- The fossil record
- Comparative morphology
- Biogeography
What are fossils
- remains or traces of past organisms
What do fossil records give?
gives a visual of evolutionary change over time
How can fossils be dated? (2)
- by examining the rate of carbon 14 decay and age of rocks where the fossils are found
- gives geological data for the organisms found
What is the half- life of carbon 14? (2)
- Decay (half-life) every 5730 years
- only good for doing organisms up to 60000 years old
What is comparative morphology?
Analysis of the structures of living and extinct organisms
Comparative morphology: what is homology?
- characteristics in related species that have similarities even if the structures differ
Comparative morphology: What is embryonic homology?
Many species have similar embryonic development
What are vestigial structures?
- Structures that are conserved even though they no longer have a use
- tailbones and appendix in humans
What is molecular homology?
Many species share similar DNA and amino acid sequences
What are homologous structures?
- Characteristics that are similar in two species because they share a common ancestor
Ex. Arm bones of many species
What is convergent evolution?
- similar adaptations that have evolved in distantly related organisms due to similar environments
Ex. Sharks and dolphins (both have fins)
Convergent evolution: what are analogous structures?
Structures that are similar but have separate evolutionary orgins
Ex. Ducks and platypus, turtle and bird beaks
How are wings in birds vs bats vs bees examples of analogous structures?
Each species have wings, but the wings did not originate from a common ancestor
What indicates common ancestry of all eukaryotes?
Structurak evidence
What are conserved across all organisms?
- many fudamental and cellular features and processes
What are cellular examples of how many fundamental and cellular features and processes are conserved across organisms? (3)
- Membrane-bound organelles
- Linesr chromosomes (recall prokaryotic genomes are circular)
- Introns in genes (no-coding segments of genome that are removed)
In terms of natural selection, how can structures become vestigial (no longer used)? (2)
- A structure may have been useful at one time, but maybe there was a mutation that rendered it useless .
- Therefore it was conserved across generations, neither being selected for or against
