Natural vs Artificial Selection
True or False: both natural selection and artificial selection can lead to evolutionary change
true
The size of a larvae depends on selective pressure and is eaten by 2 organisms: birds and wasps. Birds eat the large larvae because they are easier to spot from far away. Wasps choose the smaller larvae as they are easier to eat. What type of selection pattern does this represent?
stabilizing selection
Fossils of lobe-finned fishes, which are ancestors of amphibians, are found in rocks that are at least 380 million years old. Fossils of the oldest amphibian-like vertebrate animals with true legs and lungs are found in rocks that are approximately 363 million years old.
Three samples of rocks are available that might contain fossils of a transitional species between lobe-finned fishes and amphibians: one rock sample that is 350 million years old, one that is 370 million years old, and one that is 390 million years old.
Select the most appropriate sample of rocks to search for a transitional species between lobe-finned fishes and amphibians. Justify your selection.
Selection: Rocks from 370 MYA sample.
Justification: Transitional fossils are found between 380 MYA (when lobe-finned fishes lived) and 363 MYA (when amphibians appeared) OR between different strata/layers in the correct order.
Several different phylogenies (evolutionary trees) have been proposed by scientists. These phylogenies are useful because they can be used to
a. determine when two similar populations of a species evolved into two separate species
b. evaluate which groups of organisms may be most closely related
c. demonstrate that all photosynthetic organ-isms are members of the Kingdom Plantae
d. demonstrate that natural selection is the prevailing force in evolution
e. demonstrate which taxa (groups of organisms) contain the most highly evolved species
b. evaluate which groups of organisms may be most closely related
Finch populations were separated in the Galapagos islands by the ocean. This lead to speciation. What type of speciation does this represent?
allopatric speciation
Define evolution
the change in the genetic makeup of a population over time
In a small group of people living in a remote area, there is a high incidence of “blue skin”, a condition that results from a variation in the structure of hemoglobin. All of the “blue-skinned” residents can trace their ancestry to one couple, who were among the original settlers of this region. The unusually high frequency of “blue skin” in the area is an example of what mechanism of microevolution?
genetic drift (specifically founder effect)
Which of the following pieces of evidence best supports the hypothesis that birds and crocodilians (crocodiles and alligators) are more closely related to each other than they are to other organisms?
a. Modern birds and crocodilians utilize different niches within the same geographical region
b. Like turtles and snakes, modern birds and crocodilians build nests in which they lay shelled eggs.
c. The skulls of birds and crocodilians have an opening that is absent in the skulls of other reptiles.
d. Fossil evidence indicates that both modern birds and crocodilians originated during the Jurassic Period.
c. The skulls of birds and crocodilians have an opening that is absent in the skulls of other reptiles
Phylogeny is the evolutionary history of a species.
Describe TWO types of evidence — other than the comparison of proteins — that can be used to determine the phylogeny of organisms.
fossil records - observe past organisms.
Homology - comparison of organismal structure/form. vestigial structures. morphology of embryos; changes in gene expression during development. comparison of reproductive strategies or life cycles
DNA sequence - comparison of DNA sequence in specific genes, molecular homology
Biogeography - analysis of organism distribution
If a species goes extinct, a new niche opens up. If another species can exploit this new niche, what type of speciation may occur?
sympatric speciation
How is our general understanding of the phrase "survival of the fittest" misleading?
In vernacular “survival of the fittest” is understood to be the strongest, fastest, and healthiest organisms, but scientifically fitness is measured by the ability to survive and reproductive success.
What are the 4 random occurrences that drive evolution?
1. mutations
2. genetic drift
3. migration/gene flow
4. natural selection
List and describe 3 pieces of evidence of evolution
Can describe any of the following
fossil record, comparative morphology, biogeography, DNA/genetic info
Identify the type of prezygotic barrier that each example represents:
1.A type of fruit fly lays its eggs on the leaves of plants while other fruit fly species lay their eggs in tree bark.
2. Grey squirrels mate from August to October while brown squirrels mate from April to June.
3. The males from one species of bird have a specific mating call, while birds from another species have a different mating call.
1. Habitat isolation
2. Temporal isolation
3. Behavioral isolation
Why is evolution a theory?
Evolution is a theory because it contains a set of ideas intended to explain how organisms change over time, it is based on a wide range of data, and has been scientifically tested and supported.
9% of a population is homozygous recessive (aa) at a certain locus. Assuming that the population is in Hardy-Weinberg equilibrium, what is the frequency of the recessive allele (a)?
q = .3
The hormone prolactin has varying effects in many different animal species. All vertebrates produce prolactin, which is involved in signal transduction pathways. In mammals, prolactin stimulates the production of milk in mammary glands. In fish, prolactin plays an important role in osmoregulation. In birds, prolactin is involved in lipid metabolism.
Which of the following best explains the presence of prolactin in various vertebrate species?
a. Though all vertebrates produce prolactin, its varied uses indicate it arose as a result of convergent evolution and not as a result of common ancestry.
b. Prolactin is a homologous hormone because it has a common origin but different functions in various species.
c. Prolactin will bind only to intracellular receptors in animal species with phospholipid bilayers, so its effects are varied in different species.
d. Because of different receptors activating different signal transduction pathways within the same species, it is likely that prolactin production is a trait with highly selective pressure.
b. Prolactin is a homologous hormone because it has a common origin but different functions in various species.
Identify the type of postzygotic barrier that each example represents:
1. A male donkey and a female horse can mate to produce a mule, but mules are sterile
2. When different species of frogs and salamanders mate the zygote fails to develop or mature.
1. Reduced hybrid fertility
2. reduced hybrid viability
The theory of natural selection is based on two main observations that Darwin made... what were these observations?
2. overproduction of offspring leads to competition for limited resources
In a certain species of dog wire hair (H) is dominant and smooth hair (h). In a large randomly mating population of dogs, 15% have smooth hair. Assuming this population is in Hardy-Weinberg equilibrium. calculate the percentage of the population that is heterozygous.
48% Hh
Experimental evidence shows that the process of glycolysis is present and virtually identical in organisms from all three domains, Archaea, Bacteria, and Eukarya. Which of the following hypotheses could be best supported by this evidence?
a. All organisms carry out glycolysis in mitochondria.
b. Glycolysis is a universal energy-releasing process and therefore suggests a common ancestor for all forms of life.
c. Across the three domains, all organisms depend solely on the process of anaerobic respiration for ATP production.
d. The presence of glycolysis as an energy-releasing process in all organisms suggests that convergent evolution occurred.
b. Glycolysis is a universal energy-releasing process and therefore suggests a common ancestor for all forms of life.
What were the results of Stanley Miller’s and Harold Urey’s experiments?
They found that organic compounds and amino acids formed.