Unit 7 Lesson 7: Color and Natural Selection Flashcards
causation
when an observed event or action makes another event or action happen
Causation is always difficult to prove because there are so many external factors that are hard or impossible to eliminate during the experiment. Correlation does not always imply causation. Give an example
For example, there might be a high correlation between ice cream sales and shark attacks. This does not mean that one is causing another. However, sometimes correlation does indicate causation.
The skin has undergone many adaptations to help humans to survive in different environments. What adapations did those who live in hot open environemnts go through
Those living in hot open environments developed more sweat glands to keep cool and less hair on the body to allow the sweat to evaporate more effectively.
if one variable increases, the other would as well. This is known as a
positive correlation
If one variable increases and the other variable decreases, this is known as a
negative correlation
correlation
a relationship between two sets of variables in which one variable responds to changes in another variable
Those living in hot open environments developed more sweat glands to keep cool and less hair on the body to allow the sweat to evaporate more effectively. What did this mean
However, less hair meant that the skin was exposed to more ultraviolet radiation from the sun.
What is melanin
Melanin is the pigment that gives people their hair, eye, and skin color, and the more melanin that is present, the darker the color is.
Melanin is produced by cells known as
melanocytes
What are melanocytes
melanocytes, and it is a natural sunscreen, protecting the skin against damage from the sun.
There are two vitamins in the skin that are influenced by UV light, and they have played a role in the
natural selection of human skin color
What is folate
Folate is an important vitamin that plays a part in the activities of DNA and fetal development.
Effect of an unsuffiecnt ammount of folate in pregant women
Not enough folate in pregnant women can lead to a neural disorder known as spina bifida
UV light and folate
UV light breaks down folate when it is in blood plasma. Darker skin has more melanin, which absorbs the UV light from the sun which helps protect folate from UV breakdown.
spina bifida
the vertebra fails to fuse completely around the spinal cord. Spina bifida is severely debilitating or deadly.
Vitamin D is another essential vitamin that relies on the sun as a part of evolutionary fitness, or the ability to survive and reproduce. What are thebenfits of vitaim d
Vitamin D aids in the absorption of calcium and supports healthy bones and the immune system.
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There are certain wavelengths of UV light that start the process of making vitamin D in the skin. How does this affect people farther away from the equator
Farther away from the equator, the UV light needed for cells to make vitamin D is not enough for most of the year.
Natural selection favored people with lighter skin as they moved away from the
equator
Natural selection favored people with lighter skin as they moved away from the equator. Why
Lighter skin allowed more UV rays to penetrate the skin so that more Vitamin D could be produced by the body.
Human skin color has evolved to be advantageous in different geographical locations to support the balancing act of protecting folate and producing Vitamin D.Whats the correlation of they study
The correlation in the study is between the variables of the location of human populations and the amount of melanin in their skin.
The correlation in the study is between the variables of the location of human populations and the amount of melanin in their skin. Elaborate
As you move away from the equator, human populations tend to have less melanin and lighter skin, and as you move toward the equator, human populations tend to have more melanin and darker skin
Describe the correlation and causation in Nina Jablonski’s research.
The correlation from the research was between where populations of humans live and the amount of pigment in their skin. The causation was demonstrated when people moved away from the equator, some populations of people lost their skin pigment over time due to the need to take advantage of lower UV radiation levels in order to produce Vitamin D for proper bone maintenance.
What is the relationship between the atmospheric pollution and the color changes in the moth population?
The changes in the environment of the moths caused the change in the populations of the moths. The proportion of the melanic moths compared to the pale-colored moths increased dramatically because the melanic moths were better adapted to their environment during the industrial revolution.
A student states that the reason for the change in the moth population was due to genetic mutations. Is this statement correct? If this statement is correct, can it be made stronger? If the statement is not correct, what is the correct answer?
The statement is partially correct because mutations are due to genetic variations. However, these variations can cause some individuals to have traits that give them an advantage. When this variation is passed to offspring and is widespread in populations, then natural selection has taken place. So, the change in the moth population was not due only to genetic mutations, but also to natural selection.
