Practice Quizzes Part 1 Flashcards
As a population geneticist, you find a species of snails with more genetic diversity than humans. What does this mean?
There is more variety in the gene pool of snails than humans
From an evolutionary perspective, germ-line mutations are more significant than somatic mutations. This is because:
Somatic mutations affect only one or a few cells and only germ-line mutations will appear in an individual’s descendants
What is the result of a mutation that occurs in somatic cells?
The mutation may be expressed in the individual, but will not be passed along to its offspring
Why is genetic variation critical for evolution?
It is the source material for natural selection
Female starlings that lay clutches of four or five eggs have more surviving young than those with either larger or smaller clutches. This is an example of:
(A) genetic drift acting on clutch size
(B) directional selection acting on clutch size
(C) disruptive selection acting on clutch size
(D) stabilizing selection acting on clutch size
(D)
A particular gene in a given population of individuals has 2 alleles, A and a. The frequency of the A allele equals the frequency of the a allele. What are the expected genotype frequencies, assuming the population is in Hardy-Weinberg equilibrium?
AA=0.25
Aa=0.5
Aa=0.25
Using visual observation of phenotype to identify allele frequency rarely works because:
Multiple genes may control phenotype
Which of these 5 evolutionary forces is rare and usually not considered by population genetics?
- Non random mating
- Mutation
- Selection
- Immigration
- Genetic drift
Mutation
All the alleles present in all individuals in a species are referred to as the WHAT of that species?
Gene pool
If an assumption for the Hardy-Weinberg equation is violated, what does this mean?
(A) The allele frequencies or genotype frequencies are undergoing evolutionary change
(B) The population is adapted to its environment
(C) Mutations are increasing in frequency in the population
(D) An allele is fixed in the population
(A)
What term correctly describes change in allele frequency due to random effect of a small population?
- Immigration
- Selection
- Non random mating
- Genetic drift
- Mutation
- Genetic drift
Genetic variation in a population refers to…
Multiple alleles within a gene pool
In a hypothetical population for 1000 frogs there exists a gene with 2 alleles. 280 of the frogs are homozygous dominant (DD), and 220 are homozygous recessive (dd). What is the frequency of heterozygous in the population?
0.50
In genetics, two organisms are part of the same population if:
They are the same species and are in the same geographic area
What does the term 2pq represent in the Hardy-Weinberg relation?
The frequency of heterozygous
The differential success of alleles is called:
Selection
What does it mean to say that an allele is “fixed” in the population?
It is an indication of no genetic variation at that locus in the population
Genetic variation has two sources-mutation and:
Recombination
At the genetic level, evolution is:
A change in the frequency of an allele or genotype over time
The Hardy-Weinberg equilibrium has 5 conditions, what are they?
- A large breeding population
- Random mating
- No change in allele frequency due to mutation
- No immigration/emigration
- No natural selection
What are the 2 equations of Hardy-Weinberg equilibrium?
P + q = 1 P^2 + 2pq + q^2 =1 P=frequency of dominant allele Q=frequency of recessive allele P^2= frequency of homozygous dominant 2pq= frequency of heterozygous genotype Q^2= frequency of homozygous recessive
Ring species such as the greenish warbler complicate the biological species concept because:
At least some of their populations are reproductively isolated from one another but can still exchange genetic material
In some large groups of plants, including dandelions, oaks, and willows, the biological species concept is complicated because the process of WHAT allows gene flow to occur between good WHAT that can be Ashly distinguished based on appearance
- Hybridization; morphospecies
- Polyploidy; ring species
- Polyploidy; evolutionary species
- Hybridization; ecological species
- Allopathic speciation; ring species
- Hybridization; morphospecies
Unlike the biological species concept, the morphospecies concept relies on:
Phenotype
Which of the following species concepts might differentiate species on the basis of specific dietary requirements?
- Evolutionary species
- Ring species
- Ecological species
- Ecological species
All members of a species can in principal mate with members of the same species but of the different sex. Two populations would not be considered part of the same species if they do not actively breed (even if they potentially could)
TRUE OR FALSE?
FALSE
Horses and donkeys can interbreed, but their offspring (mules) are infertile. This is an example of what kind of reproductive isolating mechanism?
Post-zygotes, genetic incompatibility
Male birds of different species sing species-specific songs to attract mates. Females only mate with males that sing their specific song. This is an example of:
Pre-zygotes isolation
New species can form through allopathic or sympathetic speciation. Which of the following mechanisms will act more strongly on populations that are initially separated in allopathy than those initially separated in sympathy? (A) disruptive selection (B) reinforcement (C) Temporal isolation (D) Pre-zygotes isolation
(D) Pre-zygotes isolation
The longer 2 species have been separated, the greater the number of genetic differences between them?
TRUE OR FALSE?
TRUE
Is the following a representation of genetic incompatibility?
Two groups of snakes do not produce offspring because they have a different number of chromosomes
YES OR NO?
YES
In general, sympatric speciation require the action of WHAT selection acting against hybrids?
Disruptive
Two species of antelope ground squirrels are separated by the Grand Canyon. They are hypothesized to descend from a common ancestor, populations of which were separated as the canyon formed. If this hypothesis is correct, it would be an example of:
Allopathic speciation by variance
WHAT is a special case of explosive speciation in which new species form rapidly in response to numerous "open" ecological niches? (A) Allopatric speciation (B) Adaptive radiation (C) Peripatric speciation (D) Sympatric speciation (E) Co-speciation
(B) Adaptive radiation
If an organism has 4 copies of each chromosome, then it is:
Tetraploid
Imagine a scenario in which a common population of animals is separated into 2 groups by a natural event. Over-time, you might expect the 2 populations to become WHAT genetically similar. This process is known as WHAT speciation.
- More; sympatric
- More; allopatric
- Less; sympatric
- Less; allopatric
- Less; allopatric
When 2 populations have undergone divergence in allopathy long enough to be unable to produce fertile offspring, then they are different enough to be considered different species?
TRUE OR FALSE?
TRUE
Speciation can occur in the absence of natural selection; for example, in speciation that results from instances of genetic drift
TRUE OR FALSE?
TRUE
The process by which sympatric speciation might occur would most likely be the result of:
Natural selection
Define sympatric speciation
Evolution of a new species from a surviving ancestral species while bothe continue to inhabit the same geographical region
Define allopatric speciation
2 types
When biological populations of the same species become isolated from rather to an extent that prevents/interferes with gene flow
Dispersal: in which some individuals colonize a distinct place such as an island far away from the main source population
Vicariance: in which a geographic barrier arises within a single population, separating it into 2+ island populations
Define peripatric speciation
A new species is formed from an isolated peripheral population
Difficult to distinguish from allopatric
The specific types of homologies used to develop phylogenetic are shared derived characters or:
Synapomorphies
Why is the fossil record not a complete catalog of biological history?
Not all organisms fossilize with equal probability
The Burgess Shale preserves a remarkable fossil record of:
Marine life during initial diversification of animals in the Cambrian Period (505 million years ago)
In a phylogenetic tree, a node or branching point represents:
The common ancestor from which the descendent species diverged
Organisms in the same family will be all from the same genus
TRUE OR FALSE?
FALSE
Which of the following best describes the purpose of phylogenies?
- Phylogenetics names species, genus, rider, class, phylum, and kingdom
- Phylogenetics compares anatomical or molecular features
- Phylogenetics looks for patterns in relatedness
- Phylogenetics looks for patterns of relatedness and compares anatomical or molecular features
4.
Imagine you are chatting with 1 of your friends. He states that reptiles are obviously a monophyletic group, as this group contains all of the organisms (outside fish) that posses scales. This statement is:
False; as reptiles are a paraphyletic group; this group does not include birds, even through birds share a common ancestor
The tips of the branches on a phylogenetic tree represent:
Present-day groups or extinct taxa
Characters that are similar because of descent from a common ancestor are WHAT; character that are similar due to convergent evolution are WHAT?
Homologous; analogous
When selecting among multiple possible phylogenetic trees that fit our date, we commonly use the principal of _________, which means we choose the ________ possible hypothesis. In phylogenetic analysis, that means selecting the tree that represents the __________ evolutionary changes or mutations.
Parsimony; simplest; fewest
The extinction of the _________, during the end of the Cretaceous mass extinction allowed mammals to diversify through the process of _________.
Dinosaurs; adaptive radiation
To which superkingdom does the organism that causes amoebic dysentery belong?
Amoebozoa
Green algae are most closely related to:
Land plants
What superkingdom do corn and wheat belong to?
Archaeplastida
The genes in chloroplasts more closely match the genes found in cyanobacteria compared to the genes found in the nuclei of photosynthetic eukaryotes.
TURE OR FALSE?
TRUE
Why haven’t more groups within the archaeplastids developed multicellularity?
Evolution is not goal-oriented toward producing an end product with complex multicellularity; each group is successful with its current morphology