Concept 1: Natural Selection
What is natural selection?
Survival of the fittest
What is a species?
A group of organisms that can successfully interbreed and produce viable, fertile offspring
What are the five (or six) areas of science that provide evidence for evolution?
- Paleontology
- Morphology/Anatomy
- Biogeography
- Embryology
- Biochemistry
- Direct Observation
What is taxonomy?
Classification of organisms
What is evolution?
Change over time
What does "fitness" mean in evolutionary terms?
"Fitness" is how well you can survive and reproduce successfully in your environment
What are the seven patterns of evolution?
- Speciation
- Extinction
- Gradualism
- Punctuated Equilibrium
- Divergent Evolution
- Convergent Evolution
-Coevolution
How are transitional fossils used as evidence for evolution?
They provide a link between ancestral species and their more recent descendants
Ex. Archaeopteryx (birds and dinosaurs)
What is phylogeny?
The evolutionary history of a species
What are the five mechanisms through which evolution can occur?
1. Natural Selection
2. Gene Flow
3. Mutations
4. Non-Random Mating
5. Genetic Drift
What are the four principles of natural selection?
- Variation
- Overproduction
- Descent with Modification
- Adaptation
What is the difference between a prezygotic barrier and a postzygotic barrier?
A prezygotic barrier prevents fertilization from ever occuring, while a postzygotic barrier prevents the offspring from living/reproducing successfully
What is a homologous structure and what type of evolution leads to homologous structures?
Simliar structures that suggest evidene of common ancestry, a result of divergent evolution
Ex. mammal arms
As you move futher along a phylogenetic tree, do you move forwards or backwards in time?
Forwards
Do individuals evolve? If no, what does?
Individuals do not evolve, populations evolve over time
What is an adaptation?
A feature/characteristic that allows an organisms to better survive in its environment
What is divergent evolution? Give an example.
Many different species arising from one common ancestor because they adapt to different environments
Ex. mammals, fish, birds, any larger category of different species
What is an analogous structure and what type of evolution leads to analogous structures?
Features that are different structurally but the same functionally due to living in similar environments, evolved indepdently due to serving similar purposes, a result of convergent evolution
Ex. wings of different organisms, streamlined bodies
What do nodes (where a branch forms) represent on a phylogenetic tree?
A recent common ancestor between the following species on a tree
What is a vestigial structure? Give an example.
Structures with little of no function to an organism, a result of divergent evolution (common ancestry)
Ex. ostrich wings, wisdom teeth, whale leg bones
What is the ultimate source of variation in a population?
Random genetic mutations
What is convergent evolution? Give an example.
Unrelated species evole similar characteristics because they live in similar environments.
Ex. sharks vs. fish, bats vs. birds vs. insects
How is biochemistry (comparing DNA sequences) used to provide evidence for evolution?
They more similar DNA sequences between different organisms are, the more closely related they are
What does the root of a phylogenetic tree represent?
The most recent common ancestor for all of the species on the tree
Why is it bad to not finish all of a prescribed antibiotic?
Bacteria has very short life cycles, therefore many generations can be established quickly. If antibiotic resistance evolves in the population, the bacteria that survive can reproduce and pass on this advantageous trait quickly, leading to populations of bacteria that are unaffected by prescribed antibiotics. To avoid this, give the full strength of an antibiotic to kill the bacteria by completely finishing your prescription.