Charles Darwin (16.1-16.2)
Natural Selection
(16.3)
(16.3)
Evidence of Evolution (16.4)
Genes and Evolution (17.1-17.2)
Speciation (17.3)
100
Define Evolution
A process of change over time
100
What three principles did Darwin apply for natural selection?
1. The struggle for existence
2. Survival of the fittest
3. Variation and Adaptation
100
Divergent evolution, otherwise called _____, is when one species evolve into several forms due to different environmental pressures.
Adaptive Radiation
100
T or F: Mutation in a skin cell will be passed down to offspring because it is a change in the gene.
False.
Only mutations in germ cells (sperm and egg cells) can be passed down to offspring.
100
Different birdsongs that cause the birds not to mate with each other is an example of __________.
Behavioral isolation
200
What are the 3 distinctive patterns of biological diversity?
Species vary globally, Species vary locally, and Species vary over time.
200
What does fitness mean? What affect's fitness?
Fitness describes how well an organism can survive and reproduce in its environment. According to Darwin, differences in adaptations affect an individual's fitness.
200
What are the three common structures exhibited by vertebrate embryos?
Tail, notochord, pharyngeal pouch
200
Name the 3 sources of genetic variation
1. Mutation
2. Recombination during sexual reproduction
3. Lateral gene transfer
200
If two species are sympatric, what types of isolation could be preventing them from interbreeding?
Behavioral isolation and temporal isolation.
300
What did Hutton and Lyell conclude about the Earth? What is the term to describe Lyell's "way of thinking"? How did their conclusions affect Darwin?
Hutton and Lyell concluded that Earth is extremely old (thousands of years -> Millions) and that the processes that changed Earth in the past are the same processes that operate in the present.
Lyell's way of thinking: Uniformitarianism.
Darwin thought, if Earth can change over millions of years, could life change too?
300
What can lead to "The Struggle For Existence"?
Overpopulation.
300
Homologous genes and proteins are some of the most powerful evidence of common ancestry. Give an example of each (1 gene, 1 protein).
*Try explaining their functions!
Gene: Hox gene, determines head to tail axis in embryonic development
Protein: Cytochrome c, functions in cellular respiration in almost all living cells
300
Name the 5 criteria for genetic equilibrium
No natural selection, no mutation, no migration (no gene flow), no sexual selection (random mating), large population
Tip: Remember 4 No's
300
What is mechanical isolation?
Mechanical isolation is a prezygotic reproductive isolating mechanism where physical incompatibility, like differences in genitalia or flower structure, prevents successful mating or pollination between species.
400
In artificial selection, how are genetic variations important?
Natural genetic variations provided the raw material for evolution and artificial selection because they provide a variety of traits, allowing humans to choose the "best" one to breed.
400
Explain the natural selection process of antibiotic resistance in bacteria.
Bacteria in a population show variation, with some having natural resistance to antibiotics due to random mutations. When exposed to antibiotics, there is a struggle for existence, and only the resistant bacteria survive and reproduce. This is an example of survival of the fittest, as the resistant bacteria are better adapted to their environment. Over time, this leads to a population dominated by antibiotic-resistant bacteria through natural selection.
400
Why do vestigial structures degrade over time?
They lose much of their original function due to different selection pressures on the descendants, so the structures no longer serve a purpose and degrade.
400
Draw how the distribution graphs will change after the following selections occur. (Draw 3 separate graphs)
1. Directional
2. Stabilizing
3. Disruptive
400
Explain how the Galapagos Finches formed several species when they all descended from mainland finches. Explain using what we've learned (reproductive isolation)
Migration and founder effect (new population on an island after migrating from mainland)
Birds fly to other islands → geographical isolation
Different habitat conditions → adaptation → natural selection acts differently
Behavioral isolation → speciation
500
How was Lamarck's Evolutionary Hypothesis incorrect? How did he pave the way for other biologists and naturalists?
Incorrect:
1. Evolution does not mean that over time a species becomes“better”.
2. Traits acquired by individuals during their lifetime cannot be passed on to offspring.
How he paved the way:
1. Suggested that species changed
2. Tried to explain evolution scientifically with natural processes
3. Recognized a link between environment and organism's body structures
500
What are some properties / characteristics of Natural Selection? (E.g. Natural selection only acts on ____)
List 4.
1. The environment (not a farmer / animal breeder ) influences fitness.
2. Well-adapted individuals survive and reproduce.
3.From generation to generation, populations continue to change as their environment changes.
4. Natural selection acts only on inherited traits.
5.Natural selection does not make organisms “better.”
6. Natural selection doesn’t move in a fixed direction.
500
How does environmental change lead to evolution?
*Try naming examples of environmental change!
Environmental changes affect some varieties more than others, so the best adapted ones survive and breed to pass on their alleles → more frequent in the species (natural selection). As more organisms with the favorable trait survive, the frequency of the alleles changes → evolution.
Example: antibiotic resistance
500
In a certain population of plants, a partial dominant gene for flower color has two alleles, R (red) and W (white). The frequency of the R allele is 0.6, and the frequency of the r allele is 0.4. In a sample of 100 plants, 36 are red, 39 are pink, and the rest are white. Is the population in genetic equilibrium? Use expected frequency to explain.
No, it is not in genetic equilibrium.
Expected numbers with genetic equilibrium are: 36 red, 48 pink, 16 white.
*Anyone can explain potential reasons? A: Pollen from another flower population could have fertilized some flowers, causing gene flow.
500
Give two ways how destructive selection can lead to speaciation.
1. The organisms with two extreme phenotypes no longer recognize each other for reproduction purposes, resulting in behavioral isolation → gene pools no longer mix → speciation
2. Extreme phenotypes tend to survive most successfully in different areas where either extreme variation is most advantageous. Organisms migrate to areas suitable for either extremes, causing geographical isolation → gene pools change separately → speciation