Overview and Extras
A scientist performs a genome-wide analysis on chimpanzees, then compares this analysis to his own data on seven chimpanzee families to attempt to find genes correlated with late-onset fertility in chimps. What type of scientific method would this be considered? (Reductionist, Systems, etc?)
Systems biology
What is one of the main problems with the fossil record as evidence for evolution?
-Will not show soft-bodied creatures
-Environment not the best for preserving every species
A crew of about 50 White Salmon, of a 1000 individual population, begin to move south into a population of Pink Salmon. Because they are reproductively compatible, they begin to reproduce with one another. What type of force of evolution is this?
Gene flow. This is increasing the genetic variation, in this case.
Define relative fitness.
A flood creates a new river on the bank of a North Carolina beach, separating a species of the grey seagull from one another. What could this event lead to?
Allopatric speciation
What is the most general level of biological organization? What is the most specific?
Kingdom= most general
Species= most specific
Analogous. Same function, different ancestor. This is an example of convergent evolution.
Mutations always _____ genetic diversity.
Increase
Between muskrats, males often fight to have a chance to approach a female. What type of natural selection is this specifically?
Sexual selection- intrasexual selection.
In an area between the edge of a forest and the start of a swamp, round beetles and pointed beetles begin to mingle. When they attempt to mate, however, the round beetle's sperm are unable to enter the pointed beetle's eggs. What type of barrier is this? BONUS: What hybrid zone will this result in?
Gametic isolation, resulting in reinforcement of the hybrid zone.
Worms in a part of Northern Africa perform the same job as worms in a part of China-- one biologist thus classifies them as the same species, despite their outward differences. What species concept is he employing?
Ecological species concept.
Natural selection and ____ selection are both evidence for evolution.
Artificial selection. Both work to "pick" the fittest, heritable traits, (one by nature, other by humans) causing selection that leads to evolution.
You are talking to a student in 1911 who is explaining to you how individuals can evolve as communities do. Is this correct? Why or why not?
No. The smallest unit of evolution is populations.
In a population of deer, having brown fur allows them to better avoid predators in the fall season. Eventually, the proportion of brown-haired deer, compared to tan or black haired deer, increases. What type of natural selection is this?
Stabilizing.
Important: this maintains genetic variation, but lowers genetic diversity. (Think variants vs. breadth of variants)
The biological species concept says that the formation of a new species relies on...
Explain the difference between Darwin's definition of evolution and the modern definition.
"change in allele frequency" vs. "descent w/ modification."
How does Lamarck's definition of evolution differ from Darwin's? Why is he wrong?
Lamarck said acquired traits could be inherited. He was wrong because they can not-- only traits encoded in gametes.
You develop a mutation after being exposed to radiation in Beury (yikes). Why will this not act as a force of evolution?
Only gametic genetic material with mutations will be passed on and contribute to evolution. (Needs to be heritable).
In humans, being homozygous recessive for the gene 4rr makes you more prone to heart disease later in life. Being homozygous dominant for this gene, however, puts you at risk for developing lung buildup. What type of natural selection will act on humans, when talking about the 4rr gene, as a result?
Balancing selection.
In a hybrid zone, a species of yellow-bellied toad mates with a species of red-bellied toad, producing a hybrid. However, an error takes place in mitosis, leading to double the chromosome number and a fertile hybrid offspring of a new species. What is this offspring an example of?
Mutations may not contribute as much to natural selection because they are often _____ or ______. (only need 1!)
Neutral, harmful (cause death)
In a population of 100 birds, 20% are purple-tailed, while the others are multicolor-tailed. The purple-tailed trait has been shown to be recessive. Assuming this population is in Hardy-Weinberg equilibrium, what is the number of individuals in this population that are heterozygous.
.2= q^2
therefore, q= .44
therefore, p= .56
therefore 2pq=.49
about 49 individuals will be heterozygous
A hurricane leads to a massive wipe-out of a species of butterfly. What type of force of evolution is this? Does it increase, maintain, or decrease the genetic variation?
This is the Bottleneck Effect, a type of genetic drift. It decreases the genetic variation, always.
Frequency-dependent natural selection ____ genetic variation.
Preserves. Keeps many phenotypes in!
In the beginning of spring, a species of black bear and a species of lion cub produce hybrid "bions" that are also able to produce their own offspring ("bion babies"). However, by the winter of next year these "bion babies" seem to be ill-adapted to the cold, and begin to die off rapidly. What type of barrier is this an example of?
Hybrid breakdown