Evolution
What is evolution?
In this process, there is a change in heritable characteristics, and eventually changes in the gene of a population over time
Whats enables for us to study species that are now extinct or have evolved into other species?
Fossil records
What are principle differences between Lamarck and Darwin's theories on evolution?
Lamarck: inheritance of acquired characteristics and use and disuse
Darwin: Only the individuals that were the best fit could survive and these get to pass on their traits to the next generation
What are the 3 sources of variation in population?
Mutation, Genetic drift, Gene flow
T or F the heterotroph hypothesis states that the first cells on earth were anaerobic heterotrophic eukaryotes
false - everything is correct except it needs to be prokaryotes
T or F: individuals throughout their lifetime can evolve characteristics as long as these characteristics are adaptations to the environment to help them survive
False: Individuals can never evolve
The human appendix is a vestigial structure that no longer has a function in the body
True
Which scientist had the correct theory about a giraffe's long neck and why?
Darwin: Darwin suspected that ancestral giraffes actually had short necks. But because of the competition for survival, the ones with longer necks had an easier time surviving because they could find food more easily. So over time, it was these tall giraffes that were able to pass on their genes onto the next generation. So this naturally passed on tall genes or taller genes per say
What three things are needed for a stable population?
1. The population needs to be large
2. The population must be isolated from other populations
3. No mutations in the population
What is the theory behind why scientists believe eukaryotes evolved from prokaryotes and what is the key reason as to why this relationship still continues?
Theory of endosymbiosis and because this was a mutually beneficial symbiotic relationship
What are the 2 classifications of evolution and how are they different?
Microevolution is the changes in one gene pool of a population over generations and Macroevolution is speciation, the formation of an entirely new species
Organisms that have similar anatomical structure, share a common ancestor, and are most likely related to each other have Comparative ____?
Anatomy
This process can alter the frequency of inherited traits in a population in 3 different ways
Natural Selection
The process of pollen moving from one valley by the wind into another valley causing movement of alleles into or out of a population is called
Gene flow
This time period was defined as the time span (40 million years) in which virtually every major phylum appeared
Cambrian explosion
What are 6 key evidence of evolution?
Fossil records
Comparative anatomy
Comparative biochemistry
Comparative embryology
Molecular biology
Biogeography
T or Forganisms that are more closely related will have similar biochemical pathways and embryonic development
True
What are 3 general trends in which natural selection can affect a population and how are they different?
Stabilizing selection:eliminates the numbers of extremes and favors the more common intermediate forms
directional selection: One phenotype replaces another in the gene pool
Disruptive selection: This increases the number of extreme types in a population
What are the 2 types of Genetic Drifts and how do they each affect a population?
Bottleneck effect: Some major disaster or event kills off the population leading to reduction in genetic variation. The resulting population is much smaller and is not representative of the original one
The founder effect: When a small population breaks away from a larger one to colonize a new area, most likely this new group will not be representative of the old group.
Explain the cretaceous extinction and its effects
Cretaceous: 10Km asteroid crashed into Yucatán peninsula in Mexico. The theory is that this collision caused a huge cloud of debris to billow into the atmosphere, blocking sunlight for months and thus a lot of plants died. This meant a huge loss in food source for lots of animals and marine animals
Explain the difference between divergent, convergent, parallel, coevolution, and adaptive
Divergent: Occurs when a population becomes isolated (for any reason) from the rest of the species and becomes exposed to new selective pressures (causing it to evolve into a new species)
Convergent: When an unrelated species occupies the same environment, they are subjected to similar selective pressures and show similar adaptations
parallel: Describes 2 related species that have made similar evolutionary adaptations after their divergence from a common ancestor
coevolution: When 2 or more species reciprocally affect each other’s evolution through the process of natural selection
adaptive: The emergence of numerous species from a single common ancestor introduced into an environment
What are the 3 categories used to define comparative anatomy and how are they different?
Analogous structures: When something has a different underlying structure but is used for the same purpose
vestigial structures: An anatomical feature or behavior that no longer seems to have a purpose in the current form of an organism of the given species
Homologous structures: these are structures that have similar or the same underlying anatomical features
A rare disease which is due to a recessive allele (a) that is lethal when homozygous, occurs within a specific population at a frequency of one in a million. How many individuals in a town with a population of 14,000 can be expected to carry this allele?
28 individuals
What are the 6 different forms of isolation commonly cause a new species to form?
1. Geographic isolation
2. Polyploidy
3. Habitat isolation
4. Behavioral isolation
5. Temporal isolation
6. Reproductive isolation
Due to what reason did animals/plants move to land and what are some characteristics that allowed them to do so
As competition for limited resources increased in the oceans and as they evolved the traits necessary to live in a dry environment, animals and plants moved to land. They developed lungs, skin, limbs, roots, seeds, etc.