All categories

2 years ago

"What if speciation occurred in humans?" Your essay should give a clear and precise example of speciation.

Biology

1 answer:

Luda [366]2 years ago

8 0

The term speciation refers to the process by which two or more different species are produced from a single original population by different speciation mechanisms. Speciation occurs in three main steps: separation of the original population, divergence (trophic divergence, reproductive divergence, genetic divergence, etcetera), and isolation.

The most related option to speciation is B. Two populations of humans living on separate sides of the ocean. After a catastrophic event, travel across the ocean is not possible. After millions of years of separation, the two groups are no longer able to produce viable offspring together, but can still produce within their isolated groups.

Speciation occurs when the original population is divided into two groups. They inhabit different places and are exposed to varying environmental conditions. With time, each group experience many genetic changes. These mutations depend on each group´s environment and its ecological pressures, and they accumulate in time. Pressures act on individuals and make them adapt to the new environmental conditions. Generation after generation, the genotype of individuals will increase the fitness to survive and reproduce. Fixation of mutations will increase the difference between the two groups, up to the diverging point into two new species. Even is they get together again, these species will not be able to mate and produce offspring, and if they do, the new generations will not be viable or fertile.

The exposed case of two human population living on different sides of the ocean, is an example of allopatric speciation.

Allopatric speciation refers to the geographic separation of a continuous genetic background, originating two or more new geographically isolated groups. During these events of speciation, emerging new barriers impede genetic flow between groups, as the two new populations that are separated can not get together and mate anymore. These barriers might be geographical or ecological.

Different stages are involved in the allopatric speciation process:

• The emergence of the barrier.

• Interruption in the genetic flow

• Slow and gradual differentiation due to the occurrence of mutations in each population and their accumulation in time.

• Genetic divergence by natural selection and reproductive isolation, impeding the two groups to mate even if the barrier disappears.

• Prezigotic isolation mechanisms favored by selection a secondary contact between the new species occurs.

You might be interested in

What type of glial cell acts locally to maintain normal electrolyte composition of the cerebrospinal fluid?

nikitadnepr [17]

Answer:

Astrocytes

Explanation:

Astrocytes are specialized glial cells found in the brain and spinal cord, they are responsible for maintaining the electrolytic composition of the cerebrospinal fluid, induce the formation of the blood-brain barrier and act as a support and guide for neurons during migration. They keep the ionic composition of the extracellular fluid of the central nervous system through the water channels, Aquaporin-4 (AQP4) and K channels, located in the pedicle processes of the astrocytes in the perivascular space, these cells exchange K and water in said perivascular medium away from the neurons. Astrocytes selectively edematize during hypotonic stress, while neurons do not.

7 0

3 years ago

What determines whether a resource is considered renewable? *

solmaris [256]

C bc the key word is replaced

7 0

3 years ago

Is the neurone a cell, tissue or an organ?

cupoosta [38]

Answer:

Cell

Explanation:

Glial cells and neurons are the two types of cells that make up the nervous system. Four tasks are carried out by glial cells, which make up the nervous system's supporting framework: Give the neurons structural support. protect the neurons. A neuron is a specialized, impulse-conducting cell that is the functional unit of the nervous system, consisting of the cell body and its processes, the axon and dendrites. Three components make up neurons (nerve cells), which perform the integration and communication processes. Axon terminals, dendrites, and axons. The cell body, also known as the soma, is their fourth component and is responsible for the fundamental functions of neurons. In the illustration to the right, a "typical" neuron is depicted. The neuron, a specialized cell created to send information to other nerve cells, muscle cells, or gland cells, is the basic functional unit of the brain. Neurons are nervous system cells that communicate information to other nerve, muscle, and gland cells. Axons, dendrites, and a cell body make up the majority of neurons.

5 0

1 year ago

Read 2 more answers

in order for the human body to maintain homeostasis, the breakdown of glucose to release energy must be followed by the

kaheart [24]

It must be folowed by the cytoplasm. Once it pops out everything will be smooth.

7 0

3 years ago

What type of scientist is most likely to study how an ocean current changes according to the season?

Lemur [1.5K]

An oceanographer would study this (my sister is an oceanographer)

3 0

3 years ago