Which of the following observations led to Darwin's major inferences?
- Members of a population vary in their heritable traits.
- Body parts that are not used deteriorate over time.
- Although organisms can produce huge numbers of offspring, many of these offspring do not survive.
- The first and fourth answers are correct.
The first and fourth answers are correct.
Both are important observations that led to Darwin's major inferences.
A group of small fish live in a lake with a uniformly light-brown sandy bottom. Most of the fish are light brown, but about 10% are mottled. This fish species is often prey for large birds that live on the shore. A construction company dumps a load of gravel in the bottom of the lake, giving it a mottled appearance. Which of these statements presents the most accurate prediction of what will happen to this fish population?
The proportion of mottled fish will increase over time.
The mottled fish will tend to escape predation because they are camouflaged against the mottled lake bottom. The mottled fish will most likely produce more offspring.
Which of these conditions should completely prevent the occurrence of evolution in a population over time?
-The environment is changing at a relatively slow rate.
-All phenotypic variation between individuals is due only to environmental factors.
-The population lives in a habitat where there are no competing species present.
-The population size is large.
- All phenotypic variation between individuals is due only to environmental factors.
Natural selection is based on all of the following except:
-genetic variation exists within populations
-individuals who survive longer tend to leave more offspring than those who die young
-populations tend to produce more individuals than the environment can support.
-individuals adapt to there environment and, thereby, evolve.
-the best-adapted individuals tend to leave the most offspring.
Individuals adapt to their environments and, thereby, evolve
Given a population that contains genetic variation, what is the correct sequence of the following events, under the influence of natural selection?
1. Well adapted individuals leave more offspring than do poorly adapted individuals.
2. A change occurs in the environment.
3. Genetic frequencies within the population change.
4. Poorly adapted individuals have decreased suvivorship.
2->4->1->3
A biologist studied a population of squirrels for 15 years. During that time, the population was never fewer than 30 squirrels and never more than 45. Her data showed that over half of the squirrels born did not survive to reproduce, because of both competition for food and predation. In a single generation, 90% of the squirrels born lived to reproduce, and the population increased to 80. Which inference(s) about the population might be true?
A. The amount of available food may have increased.
B. The subsequent generation of squirrels developed better eyesight due to improved diet; the subsequent squirrel generation inherited better eyesight.
C. The number of predators that prey upon squirrels may have decreased.
D. A and C could be true.
E. A, B, and C could be true
D. A and C could be true
Which of the following must exist in a population before natural selection can act upon that population?
-Sexual Reproduction
-Genetic variation among individuals
-Variation among individuals in reproductive success.
-Three of the responses are correct.
-Two of the responses are correct
Two of the responses are correct.
If Darwin had been aware of genes, and of their typical mode of transmission to subsequent generations, with which statement would he most likely have been in agreement?
-A single mutation in a single gene in a single gamete will, if perpetuated, produce a new species within just two generations.
-If natural selection can change one gene's frequency in a population over the course of generations then, given enough time and enough genes, natural selection can cause sufficient genetic change to produce new species from old ones.
-If an individual acquires new genes by engulfing, or being infected by, another organism, then a new genetic species will be the result.
-If an individual's somatic cell genes change during its lifetime, making it more fit, then it will be able to pass these genes on to its offspring.
If natural selection can change one gene's frequency in a population over the course of generations then, given enough time and enough genes, natural selection can cause sufficient genetic change to produce new species from old ones.
The role humans play in artificial selection is to
choose which organisms breed, and which do not.
Currently, two extant elephant species (X and Y) are placed in the genus Loxodonta, and a third species (Z) is placed in the genus Elephas. Thus, which statement should be true?
-Species X and Y are not related to species Z
-Species X and Y share a greater number of homologies with each other than either does with species Z.
-Species X and Y are the result of artificial selection from an ancestral species Z.
-Species X and Y share a common ancestor that is till extant.
-Species X, Y, and Z share a common ancestor, but nothing more can be claimed than this.
Species X and Y share a greater number of homologies with each other than either does with species Z.
The rise of methicillin-resistant Staphylococcus aureus (MRSA) can be considered to be an example of artificial selection because
humans synthesize methicillin and create environments in which bacteria frequently come into contact with methicillin
Currently, two extant elephant species (X and Y) are placed in the genus Loxodonta and a third extant species (Z) is placed in the genus Elephas. Assuming this classification reflects evolutionary relatedness, which of the following is the most accurate phylogenetic tree? (The length of the branches reflects evolutionary time.)
4
The following question refers to the evolutionary tree figure.
The horizontal axis of the cladogram depicted below is a timeline that extends from 100,000 years ago to the present; the vertical axis represents nothing in particular. The labeled branch points on the tree (VZ) represent various common ancestors. Let's say that only since 50,000 years ago has there been enough variation between the lineages depicted here to separate them into distinct species, and only the tips of the lineages on this tree represent distinct species.
How many separate species, both extant and extinct are depicted in this tree?
6
The following question refers to the evolutionary tree figure.
The horizontal axis of the cladogram depicted below is a timeline that extends from 100,000 years ago to the present; the vertical axis represents nothing in particular. The labeled branch points on the tree (VZ) represent various common ancestors. Let's say that only since 50,000 years ago has there been enough variation between the lineages depicted here to separate them into distinct species, and only the tips of the lineages on this tree represent distinct species.
According to this tree, what percent of the species seem to be extant?
66%
The following question refers to the evolutionary tree figure.
The horizontal axis of the cladogram depicted below is a timeline that extends from 100,000 years ago to the present; the vertical axis represents nothing in particular. The labeled branch points on the tree (VZ) represent various common ancestors. Let's say that only since 50,000 years ago has there been enough variation between the lineages depicted here to separate them into distinct species, and only the tips of the lineages on this tree represent distinct species.
Which of the five common ancestors, labeled VZ, has given rise to the greatest number of species. both extant and extinct?
Both species X and Y can be considered to have given rise to the greatest number of extant and extinct species.
The following question refers to the evolutionary tree figure.
The horizontal axis of the cladogram depicted below is a timeline that extends from 100,000 years ago to the present; the vertical axis represents nothing in particular. The labeled branch points on the tree (VZ) represent various common ancestors. Let's say that only since 50,000 years ago has there been enough variation between the lineages depicted here to separate them into distinct species, and only the tips of the lineages on this tree represent distinct species.
Which of the five common ancestors, labeled VZ, has been least successful in terms of percent of its derived species that are extant?
W
The following question refers to the evolutionary tree figure.
The horizontal axis of the cladogram depicted below is a timeline that extends from 100,000 years ago to the present; the vertical axis represents nothing in particular. The labeled branch points on the tree (VZ) represent various common ancestors. Let's say that only since 50,000 years ago has there been enough variation between the lineages depicted here to separate them into distinct species, and only the tips of the lineages on this tree represent distinct species.
Which of the five common ancestors, labeled VZ, has been most successful in terms of percent of its derived species that are extant?
Z
During a study session about evolution, one of your fellow students remarks, "The giraffe stretched its neck while reaching for higher leaves; its offspring inherited longer necks as a result." Which statement is most likely to be helpful in correcting this student's misconception?
-If giraffe's did not have to compete with each other, longer necks would not have been passed on to the next generation.
-Only favorable adaptations have survival value.
-Characteristics acquired during an organism's life are generally not passed on through genes.
-Spontaneous mutations can result in the appearance of new traits.
-Disuse of an organ may lead to eventual disappearance.
Characteristics acquired during an organism's life are generally not passed on through genes.