Bio II Ch. 7 &11

Consider a gene with two alleles that show complete dominance. When two heterozygotes for this gene breed, they have a 25 percent chance of producing a homozygous recessive offspring. The next time these two individuals breed, what are the chances that they will once again have a homozygous recessive progeny?

25%

If an individual is a carrier for a recessive disorder (with one copy of the recessive allele) and his or her partner is also a carrier, what is the probability that they will produce a child affected by the disorder? Explain your answer.

25% chance they will produce a child affected by the disorder. If each is just a carrier of the disorder and doesn't have it, then they are both heterozygous. When two heterozygous traits are crossed, the ration is 3:1.

Different versions of a given gene

Allele

A change in the overall inherited characteristics of a group of organisms (populations) over multiple generations

Biological evolution

Define gene in both classical and molecular ways.

Classical: The traits that are carried from one generation to the next. Molecular: DNA must code for protein

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

Codominant traits

What type of cross did Mendel use to help him form the law of independent assortment?

Dihybrid cross

The study of organisms prior to birth or hatching is called _____.

Embryology

Dolphin embryos develop hind limb buds, but these buds disappear after a short time. What is one mechanism to explain how this change occurs in the embryo?

Embryonic development

In Mendel's controlled mating experiments, what is the name the individuals produced by crossing two true-breeding parents?

F1 generation

Two fossils are found in a hillside. Fossil A was found in an upper layer and fossil B was found in a lower layer. Which of the following statements is true?

Fossil B is the oldest

Enables biologists to reconstruct the history of life on Earth

Fossil Record

Most traits in humans involved complex inheritance where the trait is governed by the action of more than one _____

Gene

The genetic makeup of an organism is its

Genotype

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

When Mendel proposed the law of segregation, what information did he NOT have?

He did not know the location of the alleles of his traits

_____ consists of one dominant allele and one recessive allele.

Heterozygotes

Both humans and whales evolved from a common ancestor. Although our forelimbs are quite different, they are made of the same bones. What kind of trait is indicated here?

Homologous structure

Why do human embryos develop gill slits?

Human ancestors use to have gills

According to Mendel's law of _____, when gametes are formed, the separation of alleles for one gene is unrelated to the separation of alleles for other genes.

Independent assortment

Bears have thinner bones than whales. Hippopotami have intermediate bone thickness. What hypothesis does this support?

It supports that hippopotami spend part of their time living in water and part living on land.

Name the event during which Mendel's law of segregation and independent assortment are applicable

Meiosis

The two alleles of a gene are separated during meiosis and end up in different gametes- egg or sperm.

Mendel's Law of Segregation

_____ traits controlled by a single gene and unaffected by environmental conditions.

Mendellin Trait

What are the ratios of Mendel's monohybrid and dihybrid crosses.

Monohybrid: 3:1 Dihybrid: 9:3:3:1

_____ is any change in the DNA sequence that makes up a gene.

Mutation

Kangaroos are found only in Australia; this would be an example of what kind of biogeography?

Narrow biogeography

Process by which individuals with advantageous inherited characteristics for a particular environment survive and reproduce at a higher rate than do individuals with other, less useful characteristics

Natural selection

Physical expression of a gene - What you can observe as an individual

Phenotype

The observable physical characteristics of an organism are known as its _____.

Phenotype

Differentiate between pleiotropy and polygenic traits.

Pleiotropy is when a single gene influences several different traits. Polygenic genes are single traits controlled by more than one gene.

_____ traits are controlled by more than one gene.

Polygenic

What are the uses of Punnett squares?

Predict the genotype and phenotype of genetic cross

In a particular plant, two genes control leaf shape and color. Round leaves (R) are dominant to jagged leaves (r). Yellow fruits (Y) are dominant to white fruits (y). A true-breeding round-leaved, yellow-fruited plant is mated with a true-breeding jagged-leaved, white-fruited plant. What are the genotypes of the plants involved in this cross?

RRYY and rryy

Why did Mendel analyze thousands of plants while conducting his research?

There is more of a likelihood of seeing clear patters with a large data set

What would be the distribution pattern of the fossils of organisms that lived on Pangaea?

They would be widely dispersed around the world

Although they are protected in many countries, humans still hunt elephants for their ivory tusks. A mutation that results in tuskless elephants is increasing in frequency in some elephant populations. Is this an example of artificial or natural selection? Support your answer.

This is natural selection because humans are not the ones controlling the mutation in the elephants. Artificial selection is when humans control the desired traits by breeding.

The fact that small, nonfunctioning hind legs are found in the skeletons of many snakes. What does it suggest?

This suggests snakes evolved from an organism wit legs. They are called vestigial traits.

A fossil is found in Africa and South America but nowhere else in the world. What does this tell us about this organism?

This tells us that the organism once lived on the southern part of Pangaea. The organisms evolved before the Pangaea separated.

A Punnett square shows the possible ways that alleles combine to form

Trait

What do you understand by true-breeding parents?

True-breeding parents are homozygous, with two of the same alleles for a gene.

Breeding programs for farm-raised chickens result in a variety of unusual colors and feathers. Is this an example of evolution?

Yes

Can addition or loss of traits of an existing organism result in evolution?

Yes

Cultivation of corn over thousands of years has resulted in a modern corncob that looks very different from the tiny ancestral cob. Does this support the concept of evolution?

Yes

A single gene with one dominant allele for black hair (B) and one recessive allele for brown hair (b) controls hair color in mice. A male mouse with black hair mates with a female mouse with brown hair and they have 12 offspring. Are you able to determine the predicted ratio of hair color in their offspring using a Punnett square? Explain your answer.

You cannot predict the genotype without knowing if the male mouse has a homozygous dominant or heterzygous dominant trait

The evolutionary process by which a population becomes better suited to its environment over time because advantageous traits are passed from one generation to the next is called ____.

adaption

Indohyus's thick bones made it easier for this animal to wade and dive in water to evade predators and find plants to eat on the river bottom. This is an example of a(n) _____, a feature that gives an individual improved function in a competitive environment.

adaptive trait

Humans bred cows specialized for milk production by allowing female cows that produce large quantities of milk to mate only with male cows with mothers that also produced large quantities of milk. This is an example of ________ selection.

artificial

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

biogeography

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

In a genetic cross in which the heterozygous phenotype is intermediate between the two homozygous phenotype, _____ dominance is expressed.

incomplete

Continental drift is the _____ of Earth's landmasses through geologic time.

movement

The increase in antibiotic resistance in E. coli as a result of treating healthy animals with antibiotics is an example of _____ driving evolution.

natural selection

The human appendix is an example of a(n) _____ structure.

vestigial