Unit 8 Lesson 10: Analyzing Data About Traits Flashcards
The environment can play an important role in the
characteristics of organisms.
The environment can play an important role in the characteristics of organisms. Elaborate
For example, a dry season can ruin crop yields for plants that are not drought tolerant.
distribution
distribution – how the variation in traits is spread across a population
variation
variation – the different traits that are found in a population
he variation and distribution of traits in a population is due to
The variation and distribution of traits in a population is due to genetic and environmental factors.
Scientists can compare a species with two genetically similar populations that express different phenotypes under different environmental conditions. What impact do these studies have
These studies can help determine if certain traits are influenced by environmental factors. Examples of traits that can be influenced by environmental factors include gender and skin (or fur) color.
Determining the average temperature of the beach where turtles lay their eggs is one way that scientists discovered how temperature affected the gender of sea turtles. Elaborate
The temperature of the sand surrounding the developing eggs of sea turtles determines if the hatchlings will be male or female. When the sand is warmer, there are more female turtles hatched
How is the gender of alligators and croocodiles determined
The gender of alligators and crocodiles is also dependent on temperature.
Mendelian Traits
Mendelian Traits – traits that are controlled by a single gene and have little variation
Examples of a flower with mendelian traits
pea plant flower color
Some traits are expressed through polygenic inheritance, whats that
polygenic inheritance – a trait is controlled by more than one gene
Example of polygenic inheritance
An example is kernel color in wheat. The three different genes and their alleles allow for a range of variation in color.
When analyzing polygenic inheritance traits, what will scientists
When analyzing polygenic inheritance traits, scientists will observe a wide variation of the trait.
When analyzing polygenic inheritance traits, scientists will observe a wide variation of the trait. What kind of distrubiuion pattern will this result in
This will result in a bell-shaped distribution pattern, where there are not very many organisms at the extreme ends.
On a bell-shaped distribution where are the most common triats
The more common traits are those that lie in the middle of the bell-shaped distribution.
What kind of traits can a bell-shaped distubtion represent
his type of statistical analysis of expressed traits are only for traits that are given a quantitative or numerical value.
Mendelian traits tend to fall into a few distinct classes such as
the color of pea pods, plant height, and flower color. These classes do not lend themselves to this type of analysis.
Mendelian traits have limited variation in
phenotypes
Traits such as crop yield, weight of animals, and disease resistance in plants can be easily
quantified and analyzed in a distribution graph.
This bell-shaped curve is called
normal distribution
normal distribution is found all over nature. What does it mean
normal distribution – a distribution that has a bell-shaped curve with more traits being expressed in the middle and the extreme variations at each end
Most of traits in nature follow what kind of distribution
Most of traits in nature follow a normal distribution where most organisms display middle ranged traits with fewer at the extremes.
A survey of 100 high school seniors in the United States showed the following results in IQ scores.
Test Score Range
Number of Students
0 - 60
0
61 - 75
10
76 - 100
27
101 - 110
50
111 - 150
12
151 - 180
1
Would this survey of 100 students result in a normal distribution?
Look at the number of students that tested in each of the ranges. Without having to graph, we can determine that this is a normal distribution because the number of students in the middle or average range is higher than those at both extremes.
What are some examples of how the environment can influence the traits of an organism?
Dry conditions such as a drought or dry year can ruin crops that are not drought resistant. Temperature during egg development can affect the gender of some animals such as turtles and crocodiles.
Populations can be genetically similar and express different phenotypes. Analyzing the environment can help determine if it is the cause of the differences.
Is the second statement true or false?
true; Environmental factors can influence the phenotypes of organisms.
genotype vs phenotype
The genotype of an organism is the set of genes that can be found on the DNA, and the phenotype is the physical characteristics of an organism due to the genotype.
What are examples of mendelian traits
reckles on the face or dimples in the cheeks. Other examples could include a hitchhiker’s thumb and widow’s peak.
Mendelian traits are typical examples that are used to
teach genetics.
What are examples Polygenic Inheritance
An example is height in humans. There is a wide variation in height in humans, unlike other species, such as pea plants, which can be classified as simply short or tall. Additional examples of polygenic inheritance include skin color, eye color, weight, and hair color.
Where would a person who has all dominant alleles for tallness fall on the bell curve?
Since having both dominant alleles for tall would be an example of an extreme case, the person would be on the far right of the bell curve. The middle area would be for average height and the far left would be for the shortest of the population.
Where would a person who has all dominant alleles for tallness fall on the bell curve?
Since having both dominant alleles for tall would be an example of an extreme case, the person would be on the far right of the bell curve. The middle area would be for average height and the far left would be for the shortest of the population.
Think about the different variations of some traits for humans. Decide which of the following is not an example of a polygenic trait.
skin color
freckles
height
brown hair
freckles
The condition phenylketonuria, or PKU, is caused by the toxic buildup of the amino acid phenylalanine, which is found in all proteins and even some artificial sweeteners. The buildup in the blood affects nerve and brain development. PKU is caused by a mutation in a gene that affects the breakdown of phenylalanine. When foods that contain phenylalanine were removed from the diet, the effects of PKU were reduced. How does this demonstrate the relationship between a trait’s occurrence and environmental factors? Should evidence of an environmental influence cause scientists to completely ignore genetic tendencies?
The effects of PKU are not seen as often when certain foods are removed from the diet, showing that the condition is also related to environmental factors. Scientists should not ignore genetic tendencies, since a person’s environment is subject to change throughout their lifetime. Traits that may be hidden or overshadowed by an environmental effect at this moment, may prove significant when the environment changes or later in life.
