Life Science Chapter 4: Genetics

What are Mendel's three principles of heredity?

In a cross of purebred parents, all offspring will display the dominant trait Two alleles for a parent's gene separate and then each combines with an allele from the other parent to determine the offspring's trait Each allele is passed to the offspring independently of the other alleles

True/False: Natural selection has been observed to create new types of organisms.

False

True/False: Skin color, height and intelligence are controlled by a single gene.

False

True/False: The number of boxes in a Punnett Square with hybrid genotypes tells you exactly how many hybrid offspring will be produced.

False

A cross between purebred peas with inflated pods and purebred peas with pinched pods resulted in peas with inflated pods. What is the recessive trait?

Pinched pods

The process by which organisms with certain adaptations survive to pass on their traits to a greater number of offspring.

Natural Selection

How does natural selection affect a population differently than genetic drift?

Natural Selection causes the traits that best help an organism to survive and reproduce to be passed on more frequently. Genetic drift is random and unpredictable

In a population of bacteria, some of the bacteria are immune to penicillin, while most are not. After a pharmacist administers several rounds of penicillin to the bacteria culture, predict which type of bacteria will be more common. Explain

The bacteria immune to penicillin will be more common since they will be the most likely bacteria to survive and reproduce.

The allele for tall pea plants is dominant over the allele for short pea plants. Suppose a hybrid pea plant is crossed with another hybrid pea plant. Create a Punnett Square for the cross, determine the phenotypic of the offspring, and determine the percentages of the offspring that would have the recessive phenotype.

The possible phenotypes are tall (TT, Tt), the short (tt). The percentage of short plants would be about 25%.

True/False: According to Mendel, a recessive trait is hidden by the presence of a dominant trait.

True

True/False: Genetic drift would most likely occur in an animal population like a petting zoo with a dozen pygmy goats.

True

True/False: Natural selection cannot create new genetic information; it can only remove genetic information from a population.

True

True/False: Natural selection has the ability to produce the variety of dogs that we have today.

True

True/False: Some characters do not follow Mendel's principles of heredity.

True

The study of how traits are passed from one generation to the next is called the science of ?

heredity

When two traits produce a blended phenotype that is called

incomplete dominance

A population of foxes migrates into a desert region. The number of foxes with larger ears is most likely to increase or decrease?

increase

A gene has more than two possible alleles

multiple alleles

The gene that controls fur color in rabbits has 4 different alleles is an example of?

multiple alleles

An organism's genotype determines its ?

phenotype

A phenotype is what type of representation of a trait. (example: black fur)

physical

When two or more genes interact to produce a single trait

polygenic inheritance

The pod color of a pea plants is controlled by only on gene that has only two possible alleles which is an example of

simple dominance

Different forms of genes that result in different traits

alleles

A purebred pea plant with green pods (PP) is crossed with a hybrid pea plant with green pods (Pp). What is the probability that an offspring will be hybrid?

50%

If one parent contributes an (Ia) allele and the other parent contributes an (Ib) allele, their child will have what blood type?

AB

Where do Creationists and Evolutionists agree on the effects of natural selection? Where do they disagree?

Creationists and Evolutionists agree that natural selection affects populations and that those populations do change when the environment favors certain traits. They agree that certain population traits, such as fox ears, are likely to change, depending on the habitat. But Creationists do not believe that natural selection is able to allow all creatures to descend from an original common ancestor.

If a father is purebred for the dominant trait of dimples (DD) and a mother is purebred for not having dimples (dd), then you should expect the couple's children to be:

Dd

A plant that follows simple dominance and has the genotype Tt would exhibit the dominant or recessive trait?

Dominant

When Mendel crossed purebred pea plants having green pea pods with purebred pea plants having yellow pods, the offspring were all?

Hybrid peas with all green pods

A black sheep mates with a white sheep. If wool color is an example of incomplete dominance, describe the color of the offspring.

Offspring would be gray

A Tt plant is crossed with a tt plant. What genotype would you expect the offspring to have?

Some Tt and some tt

Gregor Mendel used pea plants to study heredity for what three reasons?

That it was relatively easy to cross different pea plants in order to observe the resulting offspring. That their characters, like pod color and height, were easy to observe. That the characters Mendel studies had at least two identifiable traits.

Both traits are present in hybrid offspring, but without blending is

codominance

Crossing a white horse and a black horse to produce a horse with both black and white hairs is an example of?

codominance

Crossing red-flowering camellias and white-flowering camellias to produce camellias that are both red and white is an example of?

codominance

The random change in the ratio of alleles in a population over time is called?

genetic drift

The letters that help visualize a pea plant's genetic makeup are called?

genotype

Alleles for a dominant trait are represented with what type of letters?

uppercase