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Andrej [43]
3 years ago
11

PLEASE PLEASE HELP ME!!!! (10 POINTS!)

Biology
1 answer:
Oksi-84 [34.3K]3 years ago
7 0

Answer:

 

en Espanol en Español     print print

Bottlenecks and founder effects

Genetic drift can cause big losses of genetic variation for small populations.

Population bottlenecks occur when a population's size is reduced for at least one generation. Because genetic drift acts more quickly to reduce genetic variation in small populations, undergoing a bottleneck can reduce a population's genetic variation by a lot, even if the bottleneck doesn't last for very many generations. This is illustrated by the bags of marbles shown below, where, in generation 2, an unusually small draw creates a bottleneck.

Loss of genetic variation as a result of a population bottleneck

Download this graphic from the Image library.

Reduced genetic variation means that the population may not be able to adapt to new selection pressures, such as climatic change or a shift in available resources, because the genetic variation that selection would act on may have already drifted out of the population.

Elephant seal

 

An example of a bottleneck

Northern elephant seals have reduced genetic variation probably because of a population bottleneck humans inflicted on them in the 1890s. Hunting reduced their population size to as few as 20 individuals at the end of the 19th century. Their population has since rebounded to over 30,000 — but their genes still carry the marks of this bottleneck: they have much less genetic variation than a population of southern elephant seals that was not so intensely hunted.

Founder effects

A founder effect occurs when a new colony is started by a few members of the original population. This small population size means that the colony may have:

reduced genetic variation from the original population.

a non-random sample of the genes in the original population.

For example, the Afrikaner population of Dutch settlers in South Africa is descended mainly from a few colonists. Today, the Afrikaner population has an unusually high frequency of the gene that causes Huntington's disease, because those original Dutch colonists just happened to carry that gene with unusually high frequency. This effect is easy to recognize in genetic diseases, but of course, the frequencies of all sorts of genes are affected by founder events.

Explanation:

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The purchasing function in the supply chain <em>manages everything related to the inputs of a firm, this means it deal with purchased goods, materials, and services.</em>

I hope you find this information useful and interesting! Good luck!

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Your town is planning on implementing a new wastewater reclamation plant (a connected wastewater plant and water treatment plant
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The reasons why the wastewater reclamation plant will be implemented are the well-being of the environment, as well as making the water suitable for usage for the people. By installing the plant, the wastewater will be cleaned in most part. That will mean that the water can be returned to the nature without it causing damage to it and polluting it, but instead contributing to its well-being and proper functioning. Also, part of the water will be used for irrigation, as flushing water in the toilets, for doing laundry, which will result in preserving the freshwater reserves while still having a source of water for certain needs. The fact that the water will be cleaned, also means that the local water bodies will be safe to use for recreation, as they will not be polluted.

6 0
2 years ago
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Involuntary muscle includes _________.
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Answer:

smooth muscle and cardiac muscle only.

Explanation:

because all of these muscles are involuntary meaning all of these muscles are not moveable by choice, you can not decide when to move these muscles. Foe example we can not control the heart muscles, the heart needs to pump involuntary, but the other muscles from the list we have control over. For example we can make a choice when it comes to moving some skeletal muscles, but not a choice when moving smooth muscle and cardiac muscle .

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Some molecules are too big to pass through the phospholipid bilayer of the cell membrane. These molecules need to pass through _
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These molecules need to pass through specific proteins or transmembrane proteins embedded in the cell membrane. A specific type of an integral membrane protein.
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What part of the body uses active transport to take up nutrients after concentration has reached equilibrium
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The villi of the small intestine use active transport to take up nutrients after concentration has reached equilibrium.

<h3>What is Active transport?</h3>

Active transport may be defined as the process that occurs against the concentration gradient and is mediated by carrier proteins. Metabolic energy is used to move ions or molecules against a concentration gradient.

During the process of digestion, the villi in the small intestine enthrall the soluble nutrients gradually. Over time, the concentration of nutrients in the villi acquires an equilibrium with the concentration in the gut. Until here, the nutrient uptake is carried by the process of passive diffusion.

But after attaining the equilibrium, the nutrient uptake is carried by the process of active transport.

The complete question is as follows:

What part of the body uses active transport to take up nutrients after concentration has reached equilibrium?

  • Lungs
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Therefore, the correct option for this question is C, i.e. small intestine.

To learn more about Active transport, refer to the link:

brainly.com/question/18434867

#SPJ1

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