Ecology Ch. 4

Evolution is best described as a heritable change in a population over time

Which of the following is part of Darwin’s summarization of natural selection?

More offspring are produced each generation than can be supported by the environment.

Which of the following are an example of adaptation?

An evolutionary process that changes the physiology of a population.

An evolutionary process that changes the anatomy of a population.

Identify the attributes of alleles as Mendel investigated with pea plants.

There can be more than two alleles in a population.

A sexually-reproducing organism will inherit one allele from each parent.

They can be either dominant or recessive.

Identify the results that indicate genetic differences among populations.

Lowland clones had the highest growth and flower production in lowland areas.

Phenotypic plasticity is best described as the ability of an organism to alter its form and function as a result of changes in the environment

What would most likely happen in the absence of genetic variation?

There would be no natural selection and therefore no adaptive evolution.

Specifically, we can define evolution as a change in the allele frequencies of a population from one generation to the next

An individual that receives a dominant allele from one parent and a recessive allele from the other parent would be heterozygous where the dominant trait would be expressed while the recessive trait would not be expressed

Suppose you conduct a survey of Asian lady beetles and you find the frequency of the SS genotype to be 0.64, the frequency of the SA genotype to be 0.32, and the frequency of the AA genotype to be 0.04. What is the frequency of the S allele?

0.64 + (1/2)(0.32) = 0.8

A large population that where the individuals mate at random and lacks evolutionary forces is said to be Hardy-Weinberg equilibrium

Suppose you survey a population of the Asian lady beetle and find the frequency of the A allele to be 0.4 and the S allele to be 0.6. Calculate the combined frequency of homozygous genotypes in this population.

Frequency of AA = (0.4)^2 = 0.16

Frequency of SS = (0.6)^2 = 0.36

0.16 + 0.36 = 0.52

Identify the conditions required for a population to remain in Hardy-Weinberg equilibrium.

No mutations occur that create new alleles; The population is very large; The individuals within a population freely mate with each other.

What is the effect of genetic drift on a population? The random loss of alleles in a population leading to reduced genetic variability

Which of the following is an example of stabilizing selection?

A population of freshwater fishes whose average length is 5 cm. individuals larger than 7 cm or smaller than 3 cm suffer higher mortality.

Which of the following is an example of evolutionary fitness?

A single Laysan Duck lays six eggs that all survive. After several generations, her progeny number in the hundreds.

Directional selection is best defined as selection that favors an extreme phenotype over others in a population

Phenotypic variance can be subdivided into two components: variance due to environmental effects; variance due to genetic effects

Which of the following is an example of disruptive evolution?

A population of fish where two distinct sizes of males are maintained.

Which of the following best describes adaptation?

Island tortoises evolve to be much larger to store energy for the dry season.

An allele is best described as a different version of a gene

Disruptive selection is best defined as selection that favors two or more extreme phenotypes over the average phenotype

Which of the following are summarized as part of Darwin’s theory of natural selection?

Survival and reproduction are not random; the best fit individuals are most likely to survive and reproduce in a population.

Organisms beget like organisms.

Within a population, there is phenotypic variation between individuals.

Perhaps one of the most important reasons why Mendel’s experiments on pea plants worked was: the characteristics, such as flower color, are controlled by different genes on different chromosomes

Phenotypic variation is the result of genetic and environmental influences that affect the appearance of an individual

Select the best example of an ecotype. The lowland populations of the sticky cinquenfoil

The end of the Pleistocene was brought about by rising global temperatures

Identify the importance of isolation among populations.

It increases the genetic diversity among populations.

It allows the populations to diverge genetically.

Certain alleles may become fixed in the population.

Managers wishing to restock lakes with indigenous populations of fish in the genus Coregonus would use which of the following information?

Anatomical features such as fin-ray counts.

Genetic analysis using microsatellite DNA.

A combination of genetic and phenotypic data.

Which of the following would be an example of an evolutionary distinct unit?

A population of alpine fish living in a headwater stream that is isolated from other populations and has a different number of fin-rays.

Which of the following best explains the color variations among individuals of the Asian lady beetle (Harmona axyridis)? There are many alleles in the population. Each individual beetle can inherit any combination of two alleles.

The ultimate source of variation in a population is mutation

Which of the following populations would be evolving? A large population where the frequency of a specific allele changed from 0.9 to 0.8 between surveys

Stabilizing selection in a population would work by selecting for an everage body size in a population

Species distributions are different today than they were 12,000 years ago during the Pleistocene. Identify how certain species may have changed their distributions is response to the warming trend. Species adapted to warmer environments slowly spread northward as the temperature warmed; species adapted to colder environments, such as cold-water fish, became trapped in high elevation refugia, such as headwater streams.

As a result of isolation in the populations of alpine fish in the genus Coregonus, approximately how many distinct populations are recognized? 19

An organism where the genetic makeup has been altered by either introducing or deleting genes is known as a genetically modified organism.

Small populations are often subject to inbreeding, which is the mating of close relatives

Which of the following would be an example of a negative impact of inbreeding in a population?

Female butterflies in isolated patches produced smaller juveniles, which were less likely to survive the winter.

Florida panthers, which underwent a major reduction in population, had malformed sperm, which lowered reproductive success.

Greater Prairie Chickens in relic prairie habitat in Illinois laid eggs with low hatch rates compared to other populations.

Inbreeding and genetic drift can both lead to loss of genetic variability in a population; lower fecundity and higher juvenile mortality; higher probability of extinction

Genetic variability in endemic island population is lower compared to other non-endemic island populations and mainland populations

In a small population, genetic drift will most likely result in the loss of genetic variation

Which of the following is an example of artificial selection?

Farmers selecting corn for sweet taste.

Soybeans selected by farmers to grow as freestanding plants.

The effect of genetic drift are best described as a random process that leads to a loss of genetic variability

Species that are confined to a particular geographic region are known as endemic species

A population with very few allozymes would indicate low levels of genetic diversity

Which of the following traits are used by Darwin’s finches to choose mates?

The type of the mating song; the size and shape of the beak

Heritability increases with increased genetic variance and decreases with increased environmental variance

Artificial selection is best described as the selective breeding of domesticated plants and animals

The rise of GMOs that are herbicide resistant has helped farmers in the short term by helping to reduce soil erosion by not having to till fields; reduced production cost; reducing the need for mechanical control of weeds, which saves time and money

Select the reasons why egg size in the Ural owl is under stabilizing selection.

Females that produced very large or very small eggs fledged fewer young throughout their life.

Females producing small or large eggs often had shorter reproductive lives.

Very large eggs and very small eggs were less likely to hatch.

Based on heritability, which trait would be most likely to evolve due to directional selection?

Egg size of the Ural Owl with an h^2 = 0.60

Imagine that the Chihuahua spruce population had 15 individuals and a prolonged drought kills 5 trees. What would be the most likely result to the genetic variability in this population?

The genetic variability would be reduced.

Why did Caroll and Boyd conclude that the soap berry bug (Jadera haematolama) was under directional selection?

The trait beak length was shown to be a heritable trait.

When the insect switched host plants, extreme phenotypes were under selection.

When Johnsongrass was exposed to glyphosate for several generations it was able to survive in fields even with high applications of the herbicide. When Johnsongrass was moved from fields with no exposure of herbicide to fields with moderate exposure, they all died. What do the results of this test indicate?

The herbicide would become ineffective at controlling Johnsongrass.

The genes that allowed Johnsongras to adapt to the herbicide were heritable.

Johnsongrass exposed to the herbicide were under directional selection and were able to adapt to the herbicide.

Small repeated segments of 10 to 100 base-pairs long in nuclear DNA is referred to as microsatellite DNA.

Heterozygosity is best defined as the proportion of individuals in a population that have two different alleles for a given gene.

The introduction of new species of plants with different fruit sizes had what kind of effects populations of soapberry bugs (Jadera haematoloma)?

Populations that switched to the introduced plants underwent directional selection to adapt to the new plant.

Allozymes are best described as various forms of an enzyme found in a population

When Darwin published his theory of evolution by natural selection, the prevailing mechanism of inheritance was blended inheritance which posed a problem because it was believed that: favorable traits that were rare would be blended out of the population and lost

The use of herbicides to control weeds probably has what effect on weeds? It places them under directional selection, where traits that improved resistance are selected for.

How can natural selection decrease diversity in a population? Through stabilizing selection that will remove extreme phenotypes from the population