Unit 8 Lesson 9: Organizing Data About Expressed Traits

Question 1

What are traits

Answer 1

Traits are individual characteristics of organisms, such as hair color, eye color, or blood type.

Question 2

Wht are traits determined by

Answer 2

Traits are determined by genes which are found on sections of DNA.

Question 3

What do genes carry

Answer 3

Genes carry codes that make proteins, and these proteins are responsible for the different traits that can be found.

Question 4

How can the expression of traits be organized

Answer 4

The expression of traits can be organized by the frequency, distribution, and variation of the traits in a population.

Question 5

What are alleles

Answer 5

Alleles are the different versions, or variants, of traits that are available for a gene.

Question 6

Where do alleles come from

Answer 6

One allele will come from each parent.

Question 7

When is the dominant allele expressed and what effect does its presnt have on the recessive allele

Answer 7

The dominant allele for the trait is expressed when it is present and will mask the recessive allele.

Question 8

When will recessive alleles be present

Answer 8

The recessive allele will be seen when two recessive alleles are present for the gene.

Question 9

What is genotype?

Answer 9

The combination of alleles found on the DNA is known as the genotype.

Question 10

What does the genotype determine in an organism

Answer 10

The genotype, in turn, determines the phenotype of the organism.

Question 11

What is the phenotype

Answer 11

The phenotype is the characteristic that can be observed, such as red flower color.

Question 12

What is frequency

Answer 12

frequency – the number of times a particular trait is seen in a population

Question 13

The cross of the red-flowered plant and the white-flowered plant yields offspring with a phenotype of

Answer 13

1 red:1 white. In other words, the frequency of red flowers is 50 percent, or 0.50. The frequency of white flowers is also 50 percent, or 0.50.

Question 14

genetic drift

Answer 14

genetic drift – a change in the frequency of an allele in a population from generation to generation

Question 15

what may cause genetic drift

Answer 15

a natural disaster or a smaller group of individuals moving away from the original population.

Question 16

Where are the effects of genetic drift seen

Answer 16

This is a random sampling of the population, and the effects seem to be more evident in populations of smaller size.

Question 17

Does genetic drift create new combinations of alleles

Answer 17

Genetic drift does not create new combinations of alleles

Question 18

What does genetic drfit change

Answer 18

it just changes what alleles that the population contains are expressed.

Question 19

Is genetic drift a source of genetic variation

Answer 19

This is not a source of genetic variation.

Question 20

distribution

Answer 20

distribution – how the variation in traits is spread across a population

Question 21

What does the distribusion show

Answer 21

The distribution shows how the variation in traits is spread across a population.

Question 22

How can populations with normal distributions of traits be represented

Answer 22

Populations with normal distributions of traits can be represented in a bell curve

Question 23

What is the meaning of polygenic traits

Answer 23

Polygenic traits are traits that are influenced by the genetic material in more than one gene.

Question 24

What are some examples of Polygenic traits

Answer 24

Examples of polygenic traits include skin color, hair color, and height.

Question 25

Can polygenic traits be predicted through Punnet Squaes

Answer 25

These traits are not as easy to predict through Punnett squares because they are often influenced by other environmental factors.

Question 26

What does graphing the frequencies of the different presentations of traits show

Answer 26

Graphing the frequencies of the different presentations of traits will show that most organisms in the population are in the middle, with a few at each of the extremes at the ends

Question 27

What is hair color influenced by

Answer 27

only about 2% of the world’s population have blonde hair. Hair color is also influenced by environmental factors which may cause variance in how these traits are expressed.

Question 28

Founder effect

Answer 28

occurs when a small group of individuals establish a new population away from the original and can have a reduced diversity compared to the original

Question 29

what impact does the founder effect have

Answer 29

The founder effect can impact the distribution of genetic diversity in a population.

Question 30

When does founder effect occur

Answer 30

The founder effect is when a small sample of an original population leaves and establishes a new population.

Question 31

How does founder effect impact the small population

Answer 31

The small population now has less genetic diversity than the original population because it is only a small sample from a much larger, diverse group.

Question 32

inheritable genetic variation –

Answer 32

inheritable genetic variation – changes in genetic material that can be passed to offspring

Question 33

What does genetic variation enable

Answer 33

Genetic variation enables natural selection and will increase the chances that some members of the population will survive.

Question 34

natural selection

Answer 34

natural selection – the process in which organisms better adapted to their environment tend to survive and produce more offspring

Question 35

Effect of natural selection

Answer 35

If there are any changes in the environment, the phenotype that is advantageous for the population will be the one that allows some organisms to adapt and survive.

Question 36

Is genetic drift a source of genetic variation? Why or why not?

Answer 36

No, because there are no new combinations of alleles. Genetic drift is caused by either a random event that reduces the population or a smaller group leaving the original population. Both of these events will decrease the diversity of the gene pool but does not result in genetic variation.

Question 37

Explain why graphing the distribution of traits in a population is important.

Answer 37

Graphing the distribution of traits can show where the majority of the organisms fall in the population. Any changes in the graph can indicate that there is an occurrence of natural selection taking place.

Question 38

A population of meerkat is descendent from a few light gray tailed meerkats from a large population on the southern tip of Africa. Today, the new population has a high frequency of light gray tails whereas light gray tails were rare in the original larger population. Is the high frequency of gray tails in the new population a result of natural selection or founder effect? Support your answer.

Answer 38

This is known as the founder effect. The light gray tails were rare in the original population. A few individuals carried the rare trait and established the new population, where the trait was seen with a higher frequency

Question 39

Where is genetic information located

Answer 39

Genetic information is located on DNA that make up chromosomes.

Question 40

Where are chromosomes located

Answer 40

These chromosomes are located in the nucleus of cells and control the genetic makeup of organisms

Question 41

What are genes

Answer 41

Genes are the codes for proteins that determine what traits are expressed.

Question 42

The different versions of the genes that are available for traits are known as

Answer 42

alleles

Question 43

What are examples of alleles

Answer 43

For example, there are alleles for eye color and hair color.

Question 44

There are usually two different versions of alleles, what are they

Answer 44

dominant and recessive.

Question 45

role dominant and recessive alleles

Answer 45

Dominant alleles mask or cover up other recessive traits. The recessive traits are seen only if two recessive alleles are present, and there are no dominant alleles for that gene.

Question 46

What happens if there are two dominant alleles in gene pairs?

Answer 46

In this case, neither allele can mask the other, meaning that the alleles are codominant.

Question 47

Codominance

Answer 47

neither allele is either completely dominant or completely recessive so both traits appear simultaneously

Question 47

Examples of codominance include color in some flowers and coat colors in some cattle. Elaborate

Answer 47

For example, white cows have a dominant white allele while red cows have a dominant red allele. When a white bull mates with a red cow, both colors are seen in the coat of the offspring.

Question 47

Examples of codominance

Answer 47

Examples include color in some flowers and coat colors in some cattle.

Question 48

What is **roan**

Answer 48

When a white bull mates with a red cow, both colors are seen in the coat of the offspring. This red and white spotted appearance of the coat is called Roan.

Question 49

There are some gene pairs where neither allele is dominant; what happens then

Answer 49

There are some gene pairs where neither allele is dominant, and when both alleles are present, both are expressed. The phenotype is typically somewhere between the two alleles. This is known as incomplete dominance.

Question 50

Incomplete Dominance

Answer 50

a completely dominant allele is not present so a new version is expressed as a hybrid of the two

Question 51

What are examples of incomplete dominance

Answer 51

Examples include some flower colors and curliness of human hair.