Biology 152 Unit 1 Practice Qs

In a Hardy-Weinberg population with two alleles, A and a, that in are in equilibrium, the frequency of the recessive allele a is .7. What is the percentage of the population that is homozygous for this allele? (answer in %, not decimals)

.49 (.7^2)

The whole point of doing cellular respiration is to?

"Make" energy in the form of ATP

Explain why it is populations that become more adapted to environments and not individuals.

An individual's genetic make-up can not change, so an individual can not adapt. An individual can grow and develop, but an adaptation refers to a change in the population of an entire species. The process of natural selection must occur for a species to adapt/evolve.

Give an example of a trait that may have evolved as a result of the handicap principle and explain your reasoning.

Any male dimorphism could potentially be attributed to the handicap principle. For example, male cardinals have a bright red color, which makes them easier for predators to see, while females are more likely to blend into their environment.

How did Darwin explain the differences in beak shape among Galapagos finches?

As adaptations over generations to eating different foods and as inherited characteristics that impacted survival and reproduction

Define missense mutation.

Change in one amino acid

_____________ evolution occurs when organisms that are NOT closely related become more similar over long periods of time.

Convergent

In multicellular organisms, mutations in either somatic or gametic cells can be passed on to offspring. T or F?

False

Every diploid individual has one allele for each trait. T or F

False, each diploid has 2 alleles for 1 trait

Evolution only occurs slowly and gradually. T or F

False. Evolution CAN occur slowly and gradually, however small population size, short generation time, and big shifts in environmental conditions can lead to rapid evolution.

Evolution explains the origins of life. T or F

False. Evolution explains how populations change over time, not the origins of the first cells, which define life.

Individuals can evolve. T or F

False. Evolution is a change in a population's genetic composition over generations. Individuals change over time, but their genes don't. Evolution is the change in the average value of a characteristic over time.

Natural selection gives organisms what they need to survive. T or F

False. If genetic variation allows an individual with a certain trait to survive challenges better, they may produce more offspring into the next generation.

Evolution is just a theory. T or F

False. It is a tested and verified explanation.

Survival of the fittest means only the fittest organisms of a population will survive. T or F

False. It sometimes has to do with something else - consider sexual selection (ex. peacocks and giraffes).

Natural selection involves organisms that are trying to adapt. T or F

False. Natural selection leads to the adaption of a species over time, but does not involve effort.

Every cell contains all of the DNA for an organism. What controls when and how specific genes are expressed?

Gene expression can be controlled by proteins and sequences in the DNA

Name 4 things that provide support for shared ancestry.

Genetic material that is composed of the same nucleic acids Similar nucleotide coding for amino acids Similar patterns of development in embryos (in vertebrates) Similar floral structure components in flowering plants

What do shared structural features of organisms often indicate?

Homologous developmental pathways Homologous embryonic cell groups Homologous gene sequences A shared common ancestor

Eukaryotic sexual life cycles show tremendous variation. Of the following elements, which do ALL sexual life cycles have in common? I. Alternation of Generations II. Meiosis III. Fertilization IV. Gametes V. Spores

II, III, IV

How could hybrid reproduction cause two species to fuse into one?

If the hybrid is as fit as the parents then there are no reproductive barriers

When closely related individuals mate with each other, or inbreed, the offspring are often not as fit as the offspring of two unrelated individuals. Why?

Inbreeding can bring together rare, deleterious mutations that lead to harmful phenotypes.

Define frameshift mutation.

Insertion/deletion alters sequence

In recent years, factories have become cleaner, and less soot is released into the environment. What impact do you think this has had on the distribution of moth color in the population?

Less soot accumulated on the trees, and thus, melanic moths were easier to spot. This may have led to more dark moths being eaten, therefore the proportion of light moths in the population may have increased.

What is the difference between micro- and macroevolution?

Microevolution describes the evolution of organisms in populations, while macroevolution describes the evolution of species over long periods of time.

Define silent mutation.

No change in resulting protein

What inherent characteristics of populations did both Darwin and Wallace propose were need for natural selection to lead to adaptation?

Population had to have variability within traits, Organisms often overreproduce resulting in competition for resources among offspring, Some individuals within a population are more successful at reproduction

Which of the following is a criteria for maintaining Hardy-Weinberg equilibrium involving two alleles for a gene?

Populations must be large, no mutations, no immigration or emigration

Define nonsense mutation.

Stop codon created

In what layer of rock strata would you find the oldest fossils?

The lowest layers

Name 3 things that contribute to the evidence for the theory of evolution

There are patterns in the fossil record that suggest other species have diverged from a single ancestor species. Anatomical structures in different groups appear to be modified versions of structures that might have been present in a common ancestor There are biogeographic patterns in the distribution of species that suggest a common ancestor.

How do vestigial structures support the theory of evolution?

There are some structures in organisms which appear to have no function at all. For example, penguins have reduced wings, despite being flightless. The existence of these vestigial structures supports the theory of evolution because they appear to be residual parts from a common ancestor.

What must be true in order for individuals best suited for growth and reproduction in a particular environment to contribute disproportionately to the next generation?

There must be genetic variation and favorable traits that can be inherited

The wing of the bat and the fore-limb of the dog are said to be homologous structures. What does this mean?

They are structures that are similar due to common ancestry

How does the sexual life cycle increase the genetic variation in a species?

Through independent assortment and crossing over in meiosis as well as random fertilization

Genetic variation must be present in a population before evolution can occur. T or F

True

Whether or not a trait is favorable depends on the environmental conditions at the time and thus the same traits are not always selected. T or F

True

What features do all cell's share?

a cellular solution bound by a cell membrane nucleic acids that contain genetic information ribosomes that can synthesize proteins a membrane composed predominately of phospholipids

Define adaptive radiation

a population of one species disperses throughout an area and different members adapt to unique niches/habitats

Which of the following populations is not in Hardy-Weinberg equilibrium?

a population undergoing natural selection

Changes in ____________ frequencies in a ________________ over time is part of the process of microevolution. Macroevolution focuses on changes in a _____________ over time.

allele, population, species

_____________ speciation involves geographic separation of a population while ______________ speciation occurs in a population in the same location.

allopatric, sympatric

Describe the difference between an allopolyploid and an autopolyploid

allopolyploids have chromosomes from two species, autopolyploids only have chromosomes from one species

Which type of selection results in greater genetic variance in a population?

diversifying selection

Continuing gene flow among all parts of the population is a part of punctuated equilibrium. T or F?

false

Punctuated equilibrium is most likely to occur in a large population that lives in a stable climate. T or F

false

When male lions reach sexual maturity, they leave their group in search of a new pride. This can alter the allele frequencies of the population through which of the following mechanisms?

gene flow

Allopatric speciation may occur because ____________ prevent ______________

genetic barriers, gene flow

One of the original Amish colonies rose from a ship of colonists that came from Europe. The ship's captain, who had polydactyly, a rare dominant trait, was one of the original colonists. Today, we see a much higher frequency of polydactyly in the Amish population. What is this an example of?

genetic drift, founder effect

Population genetics is the study of:

how selective forces change the allele frequencies in a population over time

What types of mutations can result in a change in the order of genes in chromosomes?

inversions, reciprocal translocations

When the hybrids are _____________ than the parental species, reinforcement of speciation in hybrid zones can occur.

less fit

Define post-zygotic isolation

mechanisms that prevent offspring from reproducing (make them infertile)

Define pre-zygotic isolation

mechanisms that prevent reproduction prior to embryo formation

The original source of all genetic variation is _____.

mutation

Which of the following evolutionary forces can introduce new genetic variation into a population?

mutation and gene flow

Most mutations are __________ and ____________

random, spontaneous

Which term is used to describe the continued divergence of species based on the low fitness of hybrid offspring?

reinforcement

When males and females of a population look or act differently, it is referred to as ?

sexual dimorphism

Define dispersal

some individuals from a main population colonize a distant place

What are some of the key aspects of adaptive radiation?

specialization of groups of individuals to specific niches/habitats multiple speciation events occurring

Two species of wild lettuce grow in the same areas, but one flowers in early spring and the other flowers in summer. What is this is an example of?

temporal isolation

Define vicariance

the isolation of two or more populations as a result of the rise of a geographic barrier within a single population

What has an impact on the rate at which mutations occur in cells?

the number of times DNA is replicated the efficiency of DNA proofreading and repair mechanisms the type of molecule used to store genetic information

A ____________ occurs when one purine is substituted for different purine. (or pyr. for pyr.)

transition

A ____________ occurs when a purine is substituted for a pyrimidine. (or pyr. for pur.)

transversion

What is assortative mating?

when individuals mate with those who are similar to themselves

The good genes hypothesis is a theory that explains what?

why individuals of one sex develop impressive ornamental traits