Lecture 8: Evidence for Evolution Flashcards
What are some predictions you can make based off of Darwin’s theories?
- There should be variation among individuals within a species and the variation should be heritable
- There should be evidence of differential survival and reproduction within populations
- If there has been common descent, then molecules and cells should indicate that life has a shared history
- The anatomy and structure of organisms should indicate they shared a common ancestor
- There should be evidence of transitional (or intermediate) forms in the fossil record
- There should be evidence for extinction
Darwin didn’t know about genetics and knew very little about the fossil record at the time (T/F)
T
What is another word for “differential survival and reproduction within populations”
What is an example?
Natural selection, Biston Betularia
Molecular homologies
When molecules and cells indicate that life has a shared history
Give a list of similarities of molecular features that are shared due to common ancestry (7)
- The Central Dogma
- Making proteins and RNA, and copying DNA
- All cells have membranes composed of lipid bilayers
- The same 20 amino acids
- DNA code for protein synthesis
- Basic biochemical pathways
- The Building blocks that create the diversity of chemicals
What are vestigial traits and Why are they important?
q
Structures that are reduced or incompletely developed but clearly show similarity to functioning structures in closely related species (such as the tailbone)
They give hints to common ancestry
Transitional feature
A trait in a fossil species that is intermediate between those of older and younger species
Important things about Archaeoptoryx
1) Their fossils have a few characteristics of modern birds that most dinosaurs did not have
2) Display many traits in common with dinosaurs
Therefore, it represents the transition from birds to dinosaurs
Why is it difficult to find transitional forms for some species
The fossil record is so sparse and the evidence for transitional forms are incomplete
Living fossils
Some organisms have remained unchanged throughout time despite being extinct ie. the coelacanth
End-Permian extinction
The largest mass extinction that occurred 205 million years ago in which 80-96% of all species disappeared (especially Marine)
End Cretaceous or the K-P Extinction
What is a possible reason for this?
The most recent and best known mass extinction which is when the last living dinosaur vanished from Earth
Evidence believes a large asteroid hit the Gulf of Mexico putting dust in the air and altering the environment
What is the current episode of mass extinction due to?
Human meditated extinction at a rate if 1000 to 10000 times above background
