Bio 1000 Exam 3

What is the total number of alleles present for any given gene in a population of 100 individuals?

200

Humans have ______ pairs of homologous chromosomes.

23

A pea plant that is heterozygous for the flower color gene makes gametes. What is the probability that a specific gamete contains the recessive allele for flower color

50%

What is biological evolution?

A change in properties of groups of organisms over many generation

What is genetic drift?

Chance evolutionary change occurring in small populations.

How closely related two DNA molecules, and the organisms from which they came, are is measured through

DNA sequence similarity

A population of mammals displays a variety of fur thicknesses. Over time as the climate cools, those individuals with the thickest fur survive better, live long enough to reproduce, and pass on their genes to their offspring. What kind of natural selection is represented here?

Directional selection

Convergent evolution occurs when natural selection causes distantly related organisms to

Evolve similar structure in response to similar environmental challenges

In Mendel's controlled mating experiments, the individuals produced by crossing two true-bleeding parents are referred to as the

F1 generation

The zygote fails to develop is an example of a postzygotic barrier.

False

Two organisms with the same genotype are homozygous.

False

The individual who used data from breeding garden peas to discover the patterns of inheritance that form the foundation of modern-day genetics was

Gregor Mendel

For a Mendelian trait, the genotype BB is also referred to as

Homozygous dominant

Horses and donkeys can reproduce and have viable offspring, a mule. Mules are not fertile and cannot reproduce. What barrier to reproduction is happening here?

Hybrid Sterility

Most human genetic characters are controlled by ____ than one gene

More

What are the functioning units of the kidneys where wastes are filtered from the blood?

Nephrons

Select the correct pathway of air through the respiratory system after leaving the nasal cavity.

Pharynx, trachea, bronchi, bronchioles, alveoli

In humans, the "master sex switch" that determines whether an embryo will become a male is the

SRY gene

One side of the heart pumps blood into the pulmonary circuit, and the other side of the heart pumps blood to the systemic circuit. How do these different functions affect the structure of the heart?

The left side of the heart has a thicker muscular wall than the right side

: All of the following can create reproductive isolation: prezygotic mating rituals, rapid and severe changes in geographic features, and gamete incompatibility.

True

A pedigree could be used to look at three young boys who are first cousins show symptoms of a neurological disorder. T

True

Both chromosomes in pairs 1-22 have the same genes at the same loci, but the alleles may be different on the two chromosomes.

True

For a woman who is heterozygous for a given gene all of her eggs will contain one allele or the other but not both alleles

True

Hemoglobin binds to oxygen and releases it near cells that are performing cellular respiration.

True

Mendel's law of segregation states the two alleles of a gene separate during meiosis and end up in different gametes.

True

There are animals that have DNA sequences for genes for some of the same proteins as humans do. This suggests humans and these animals evolved via common descent from a common ancestor.

True

Two fossils are found in a hillside. Fossil A was found in an upper layer, and fossil B was found in a lower layer. B is likely the oldest of these fossils

True

When Mendel proposed the law of segregation, he did not know the location of the alleles for flower color.

True

If a homologous trait is no longer useful in a specific organism, then it is referred to scientifically by what term?

Vestigial trait

In humans, on which chromosome is the master gene that determines the sex of an individual with help from other genes it controls?

Y chromosome

A genetic bottleneck is a type of genetic drift in which

a population is reduced to very to very few individual and alleles are lost

Birds and insects both have wings for flying through the air. In this example, wings are ____ ___.

adaptive trait

A large population of animals is split in two by a physical barrier. Over time, the genetic makeup of the two resulting populations becomes more and more different until each population becomes a separate species. This is an example of

allopatric speciation

In cystic fibrosis, parts of the respiratory tract can become clogged with mucus, inhibiting gas exchange. The areas of the respiratory tract where gasses are directly exchanged is the

alveoli

87. Pangaea is

an ancient, giant continent

Blood vessels that are designed to carry blood under high pressure are called ________. Blood vessel that have thin, porous walls are called

arteries; capillaries

Humans simulate the process of natural selection when they use _______ to develop new varieties of crop plants that better meet the needs of farmers

artificial selection

Chromosomes that are NOT involved in determining gender are known as

autosome

The liquid portion of human blood cannot absorb enough oxygen to meet the body's demands. However, _______ in red blood cells greatly increases the oxygen-carrying capacity of human blood.

bamoglobin

The geographic locations where an organism (or its fossils) can be found are described as the species

biogeography

Individual organisms with inherited characteristics that enable them to survive and reproduce are said to have greater _______ fitness than individuals who fail to survive and reproduce.

biological

. Based on the _______ concept, organisms that interbreed and produce fertile offspring are most likely classified as a species.

biological specials

The force of blood pushing against the walls of blood vessels is called

blood pressure

The parts of the central nervous system include the

brain and spinal cords

The blood vessels that allow diffusion between blood and nearby body cells are

capillaries

A female who is heterozygous for a sex-linked recessive condition is referred to as a

carrier

An X-linked carrier is a female individual with a _______ genotype, on her X chromosomes, who does not express the recessive trait but can pass it along to offspring.

carrier

On chromosomes within an individual, there are ________ alleles for a given gene found on ________ chromosomes.

chromosome; two homogous

When the effect of the two alleles is equally visible in the phenotype of the heterozygote, the pair of alleles shows which mode of inheritance?

codominance

If two different alleles for the same trait have an equal effect on the phenotype, the alleles are

codominant

In many predator-prey relationships, evolutionary change in the prey will result in evolutionary change in the predator, a phenomenon known as

coevolution

There is a species of ant that lives on Acacia trees. Over time, the ants have evolved behaviors that protect the tree from being eaten by herbivores. The Acacia tree has evolved hollow thorns in which the ants can live and build nests. This is an example of

coevolution

Two species evolving together in response to interactions between the two species is referred to as

coevolution

. An organism from which more than one species has evolved is referred to as a(n) _______. The group of organisms arising from it have a common descent.

common ancestor

. DNA is the genetic (hereditary) material found in all living things on planet Earth. The genetic code is the same for everything from bacteria to plants and humans; this is evidence that the great diversity of life evolved from a

common ancestor

About 600,000 people die of heart disease in the U.S. every year. Researchers have identified alleles associated with increased risk of heart disease, but it is estimated that 30 percent to 40 percent of the annual deaths due to heart disease could be eliminated by physical activity in people who are genetically predisposed to heart disease. This is an example of a

complex trait influenced by the environment_

Two unrelated species evolving to look more similar due to environmental pressures is called

convergent evolution

Two different species may have similar features because of _

decent from a common ancestor

The branched structures on a nerve cell that receive information are called

deodrites

The red-breasted nuthatch and the white-breasted nuthatch are similar in appearance and, in many regions of the United States, their ranges overlap. The two organisms do not interbreed. Based on this information, red-breasted and white-breasted nuthatches are

different species

In a shallow bay, a population of oysters is the food source for the local crabs. The lightest colored oysters blend with the color of the rocks, and darkest colored oysters are concealed in the shadows cast by the rocks. Oysters with an intermediate coloring are easily detected by the crabs and become a tasty meal for them. Over time, fewer and fewer oysters display the intermediate coloring, while more oysters are either the lightest coloring or the darkest coloring. This is an example of

disruption selection

Over time, two populations of a penguin species become increasingly genetically dissimilar from each other. This accumulation of changes in the DNA sequences is recognized first as

divergence

Two genes control fur color in Labrador retrievers. The first gene determines whether the pigment to be deposited in the hairs will be black or brown. The second gene determines whether the pigments are put into the dog's hairs at all. A dog homozygous for the recessive allele of this second gene will always be yellow because no pigment is deposited in its hairs, regardless of the alleles of the first gene. This is an example of

espistasis

The preserved remains of formerly living organisms are called

fossil

Mendel used _______ as his research organism to study patterns of genetic inheritance.

garden pea

Which of the following is a stretch of DNA coding for a single protein?

gene

Geographic isolation limits the ______ between separated populations of a species.

gene flow

Horizontal gene transfer is an example of

gene flow

Researchers hope to develop treatments for sex-linked genetic disorders such as Wiscott-Aldrich syndrome (WAS), by using a virus to insert a functioning gene into the patient's blood cells. This technique for correcting defective genes is called _______, which is one form of genetic engineering.

gene therapy

In a small population of beetles, some of the beetles were brown and others were green. A volcano erupted nearby. By chance, most of the beetles that survived were green. This is an example of

genetic bottleneck and genetic drift

Mutations will affect the

genotype

If an individual has two alleles at a given locus that are different, the individual is said to be ______ for the gene

heterozygous

Both humans and whales evolved from a common ancestor. Although our forelimbs are quite different, they are made of the same bones. This is an example of a(n)

homologous structure

Bacteria often store genes on small, circular pieces of DNA called plasmids. The process of transmitting these plasmids and the genes they contain to other bacteria is called____ gene transfer and is an example of gene flow

horizontal

Scientists use a pedigree for what purpose

learn about traits of family

Every gene in a human occupies a specific position or ______ on a chromosome.

locus

The trachea is part of the _______ respiratory system.

lower

Blood leaving the right ventricle of the heart travels next to the

lungs

Mendel's laws of segregation and independent assortment both have their biological basis in events that take place during

mitosis

For a population to evolve, there must be genetic differences between organisms in that population. These differences arise by

mutation

New alleles arise by

mutation

Grasshopper mice prey on venomous scorpions. Though the mice have some level of resistance to the scorpion venom, scorpions with more potent venom are better able to fend off attack by a grasshopper mouse. Over time, the population of scorpions all produce more potent venom. This is an example of __________ selection.

natural

Fossils found in deeper layers are _______ than fossils found in more shallow layers.

older

Gene flow occurs

one population joins another

Natural selection acts directly on _______ that increases survival and reproductive success.

phenotype

Snapdragon flower color displays incomplete dominance. Therefore, when a homozygous red flower is crossed with a homozygous white flower, the offspring will be

pink

The observation that individuals afflicted with albinism also always have vision problems is an example of

pletotrophy

Most inherited single-gene genetic disorders are inherited as _______ alleles.

recessive

In order to contribute to the evolution of one's species, an individual must survive in its environment long enough to

reproduce

The great diversity of life on Earth is caused by the formation of new species in a process known as

speciaiton

In gene therapy, a viral vector is mixed with bone marrow cells taken from the patient. The bone marrow cells are an example of which cell type?

stem cells

The two left chambers of the human heart form the _____ circuit and pump blood from the heart to the ____

system; cells of the body performing cellular respiration.

Girls inherit an X from their mom and an X from their dad.

true

A species of cave beetle that lives in total darkness is blind but has remnants of what looks like eyes. These "eyes" are

vestigial

Whales have tiny thighbones embedded in the skin next to their pelvis. This is an example of

vestigial structure

Fossils of organisms that lived on Pangaea are likely found

widely dispersed throughout the world