About 3 million years ago, the Isthmus of Panama (a narrow strip of land connecting North and South America) formed, dividing marine organisms into Pacific and Caribbean populations. Researchers have examined species of snapping shrimp on both sides of the isthmus. Based on the morphological species concept, there appeared to be seven pairs of species, with one species of each pair in the Pacific and the other in the Caribbean. The different species pairs live at somewhat different depths in the ocean. Using mitochondrial DNA sequences, the researchers estimated phylogenies and found that each of these species pairs, separated by the isthmus were indeed each other's closest relatives. The researchers investigated mating in the lab and found that many species pairs were not very interested in courting with each other, and any that did mate almost never produced fertile offspring. Which process led to the formation of the species pairs of Pacific and Caribbean snapping shrimp

Answers

Answer 1

Answer:

Allopatric speciation

Explanation:

Allopatric speciation refers to the geographic separation of a continuous genetic background, originating two or more new geographically isolated groups. These divergences of the original population might be related to migration in different directions, extinction of geographically intermediate populations, or geological events. 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.

The Panama isthmus is an example of allopatric speciation caused by an extrinsic geological barrier that interrupted the genetic flow between species driving to genetic changes and reproductive isolation.  

Two different groups that evolved in allopatry might meet again in secondary contact if the barrier that separated them, disappears. In the Panama isthmus example, the groups that did mate, could not produce any fertile progeny because of postzygotic reproductive isolation. And the groups that did not mate, were not attracted to each other because of prezygotic reproductive isolation.  


Related Questions

where does osmosis take place

Answers

Answer:

In Gastrointestinal system:

When we eat food or drink water, it travels from our mouth, down our oesophagus and into our stomach. In the stomach, the food is broken into tiny pieces that are mixed with stomach liquids. This mush of food and stomach liquids is called chyme. The chyme travels into the small intestine. This is where osmosis takes place.

In our Kidneys:

Our kidneys keep blood and tissue fluid (internal environment) 'clean' by removing urea, excess water and other wastes and excreting them. This controls the amounts of dissolved substances in blood and tissue fluid, a process called osmoregulation. If tissue fluid becomes too concentrated, cells will lose water by osmosis and become dehydrated and if it becomes too dilute, cells will take in excess water by osmosis.

Why is it that we use the two-name binomial nomenclature invented by Carl Linneaus still to this day?
A. Because mountain lions and pumas are actually very different animals.

B. Because the system is widely accepted and used all over the world universally.

C. Because everybody knows how to speak Latin and Greek.

D. Because Carl Linneaus was just that important.

Answers

Answer:

B. Because the system is widely accepted and used all over the world universally.

Explanation:

In contrast to earlier names that were made up of diagnostic phrases, binomial names (or “trivial” names, as Linnaeus himself called them) conferred no bias about the quality or value of plant species named. Rather, they served as labels by which a species could be universally addressed.

Answer:

B. Because the system is widely accepted and used all over the world universally.

Explanation:

We use the two-name binomial nomenclature invented by Carl Linneaus still to this day because, the system is widely accepted and used all over the world universally.

The Pearson Correlation Coefficient is a tool used in understanding the behavior of gene expression. A positive ratio means a gene is induced in cancer cells and is transcribed at a higher rate. A negative ratio means a gene is suppressed in cancer cells or is transcribed less frequently than in normal cells. What form of gene expression do you think would lead to a correlation coefficient of one

Answers

Answer:

the gene is being expressed at an equal rate in both cell types

Explanation:

In statistics, the Pearson correlation is a linear measure of the association between two continuous variables. The Pearson's Correlation Coefficient may exhibit values between -1 and +1. A value equal to 1 shows a perfect correlation, indicating that when one variable increases the second variable also increases (when this value is +1) or decreases (when this value is -1). Moreover, when the Correlation Coefficient is equal to 0 it means that there is no correlation.

What’s an opinion you have about genetic testing?

Answers

Answer:

Genetic testing is useful in many areas of medicine and can change the medical care you or your family member receives. For example, genetic testing can provide a diagnosis for a genetic condition such as Fragile X or information about your risk to develop cancer. There are many different kinds of genetic tests

1) A specialized function shared by the many cells lining the lungs and the lumen of the gut isA) decreased oxygen demand due to the lack of oxygen in foods.B) increased exchange surface provided by their membranes.C) greater numbers of cell organelles contained within their cytoplasm.D) greater protection due to increased cellular mass.E) lowered basal metabolic rate due to cooperation between cells

Answers

Answer:

B) increased exchange surface provided by their membranes

Explanation:

Alveoli are tiny air sacs that are responsible for exchanging oxygen (O2) and carbon dioxide (CO2) in the lungs. Alveoli have elastic fibers in order to expand and recoil depending on the volume of air breathed in. The alveolar epithelial cells (pneumocytes) may adopt a shape that serves to increase the surface area of gas exchange. On the other hand, intestinal epithelial cells have microvilli, which are microscopic projections in the plasma membrane. Microvilli serve to increase the cell's surface area, thereby facilitating the absorption of nutrients and water.

Answer:

B) increased exchange surface provided by their membranes.

Explanation:

The intestine that characterizes by being folded, and by having its walls covered by villi that project into the lumen. They are more concentrated in the first portion of the intestine, decreasing to the final region of the organ.  They are involved in nutrients absorption by increasing the absorption area.

Nutrients are absorbed by primary cells and transported to the bloodstream.  Mucus is secreted to protect the epithelium during digestion. Villi also transport water from the blood to the intestinal tract, which helps in food decomposition.

Besides the absorption function, the intestine characterizes by doing the peristaltic movement, secretion through special glandules, digestive function, absorptive functions, secretion functions, and endocrine functions.

Animals must have a respiratory membrane to make gas interchange. This surface must be humid, thin, and revested by a simple plane epithelium, plenty of vessels. The membrane must be permeable and exposed for gases to circulate. This membrane might be on the body surface or in specific respiratory organs, such as lugs. The gas exchange occurs by simple diffusion. Oxygen tends to diffuse to the interior of the organisms, while carbon dioxide tends to get out of it.

Help Brainliest to anyone who answers me ASAP!!!
Which scenario is an example of a negative feedback loop?
A.
When body temperature increases, sweat is produced as a cooling agent to lower body temperature.
B.
In some parts of the world, birth rates are far exceeding death rates, which has led to overpopulation.
C.
Ice reflects sunlight much better than water. A warmer atmosphere is turning ice to water, which is absorbing more of the Sun’s energy.
D.
A warmer atmosphere is leading to warmer oceans. A warm ocean releases more carbon dioxide, which traps more heat in Earth’s atmosphere.

Answers

Answer:

A)

Explanation:

Question has been asked before so I know the answer.

What will you have in 500 years????

Answers

Answer: You Palpatine, I'd still have you.

Explanation:

How does mining impact the enviorment

Answers

Environmental impacts of mining can occur at local, regional, and global scales through direct and indirect mining practices. Impacts can result in erosion, sinkholes, loss of biodiversity, or the contamination of soil, groundwater, and surface water by the chemicals emitted from mining processes.

Answer:

Mine exploration, construction, operation, and maintenance may result in land-use change, and may have associated negative impacts on environments, including deforestation, erosion, contamination and alteration of soil profiles, contamination of local streams and wetlands, and an increase in noise level, dust

Mitosis makes.....
A. cell phones

B. identical body cells

C. sperm and egg cells

Answers

B. identical body cells

hope it is helpful to you

Answer:

B. identical body cells

Explanation:

Mitosis produces new cells, and replaces cells that are old, lost or damaged. In mitosis a cell divides to form two identical daughter cells. ... Mitosis separates these chromatids, so that each new cell has a copy of every chromosome.

What is the difference between gene mutations and chromosome mutations?
A. Gene mutations are preventable and chromosome mutations are not

B. Gene mutations can happen easily and chromosome mutations are more difficult

C. Gene mutations only affect one gene while chromosome mutations affect many genes

Answers

Answer:

C. Gene mutations only affect one gene while chromosome mutations affect many genes.

Explanation:

The difference is that the gene mutations only affect one gene while chromosome mutations affect many genes.

water is warmers by the sun and ?

Answers

Answer:and then it evaporates into the atmosphere

Explanation:

What does stage 4 show?
A. A young female cone with fertilized eggs matures into a seed
cone.
B. A spore divides and grows into a pollen grain using mitosis.
C. Young male cones produce spores using meiosis.
D. A seed that contains an embryo plant grows into a young pine
tree.

Answers

Answer:

A.

Explanation:

It looks like the pine cone looks like is turning into a normal cone. That is why.

Answer: A. it looks as if its matured from being a young cone

Red-green color blindness is an X-linked recessive disorder that is passed through generations and can be traced by using a pedigree.

A pedigree is shown. Sam, Bella, Joshua, and Tim have filled-in shapes. Lisa and Monica have half-filled shapes.

Which individuals in the pedigree are identified and labeled carriers for red-green color blindness?
Lisa and Monica
Sam, Tim, Bella, and Joshua
Ben, Jenny, Mike, Carol, Katie, and Chris
Ben and Lisa

Answers

They all have the disease. However, carriers are generally consider those who can give the disease, but don’t have it themselves. This would make the answer Lisa and Monica as they have the recessive gene, but only have one allele, meaning they carry the gene for color blindness, but fortunately do not have it due to the dominant allele being normal.

Answer:

Lisa and monica

Explanation:

just took the test :))

Which is not a major reservoir of carbon?
O rivers and lakes
O oceans
O living things
O fossil fuels

Answers

Answer:

i think its fossil fuels but dont dont quote me on that

what find of spider of this kind of spider is this?

Answers

Answer:

Fishing Spider

Explanation:

Dolomedes is a genus of large spiders of the family Pisauridae. They are also known as fishing spiders, raft spiders, dock spiders or wharf spiders

That is a fishing spider!! Hope this helps!

What are substances that make the plant body erect?

Answers

Answer:

The root system, which supports the plants and absorbs water and minerals, is usually underground. The organ systems of a typical plant are illustrated below. The shoot system of a plant consists of leaves, stems, flowers, and fruits. The root system anchors the plant while absorbing water and minerals from the soil.

hi! can someone help with this question?

"Why is the nitrogen cycle essential to plant and animal life?"

Answers

Answer:

Plants and animals could not live without nitrogen. It is an important part of many cells and processes such as amino acids, proteins, and even our DNA. It is also needed to make chlorophyll in plants, which plants use in photosynthesis to make their food and energy

Scientists often look for similar genes in very dissimilar organisms as evidence that they are related.
O True
False

Answers

Answer:

True

Explanation:

What is a mutation?

A. A change that occurs in RNA only

B. A change that occurs in DNA only

C. A change that occurs in DNA or RNA

Answers

[tex]\huge\colorbox{purple}A\colorbox{blue}n\colorbox{purple}s\colorbox{blue}w\colorbox{purple}e\colorbox{blue}r [/tex]

[tex]\color{Violet}\rm{Heree!}[/tex]

For me the answer is letter B.

hope it's help✨

__________________________________

“‘The mountains may shift, and the hills may be shaken, but my faithful love won’t shift from you, and my covenant of peace won’t be shaken,’ says the Lord, the one who pities you.” — Isaiah 54:10 ❤

__________________________________

Answer:

C. A change that occurs in DNA or RNA

Explanation:

A mutation is a change that occurs in our DNA sequence, either due to mistakes when the DNA is copied or as the result of environmental factors such as UV light and cigarette smoke.

Name the site of erythropoiesis in adults

Answers

Answer:

Explanation:As stated above, in adults the principal sites of red cell production, called erythropoiesis, are the marrow spaces of the vertebrae, ribs, breastbone, and pelvis.

hey i would really appreciate if someone helps me out
1. Why should we care that the panthera tigris is going extinct? Explain how humans might be affected by the loss of the panthera tigris.

Answers

Answer: I believe tigers, also known as "Panthera tigris" are important to humans because they balance the ecosystem. When creatures go extinct they leave behind a scar that affects the ecosystem that is around them. Since Tigers are secondary consumers they control natural prey populations. The connection to the food web is very important and essential to keep this food web stable. Once something goes extinct it will cause the food web to shift and some primary producers will go out of control.

Explanation: Not sure if this helped at all this is just what I know about the food web. Panthera Tigris are secondry consumers so they control the primary producer population. This is just basic food web and ecosystem thinking. This is how they impact humans if they go extinct.

Which of the following best explains how meiosis, followed by fertilization, ensures genetic variation?

Answers

Answer:

Having two phases of meiosis allow for more unique cells to be produced. Meiosis is a form of asexual reproduction which leads to more genetic variation. Meiosis produces 4 haploid daughter cells which all contain identical DNA segments.

Explanation:

hope this helps  if not I'm sorry

Which of these can lead to the extinction of a species?
Plz help

Answers

Answer:

Explanation:

It would be A because if you lost your home they will be killed by predictors

A multicellular organism. Define multicellularity and explain how you know this organism is multicellular.

Answers

Answer:

A multicelular organism

Explanation:

You can tell an organism is multicellular because it contains more than one cell. It has many cells that help build the organism.

Which example below is a concern related to nuclear energy?

long-term storage of waste

supplemental energy may be needed if weather is not ideal for energy collection

can be unsightly and/or noisy

potential for floods

Answers

Answer:

C. can be unsightly and/or noisy

Explanation:

Answers A, B, and D correspond with fossil fuels (fracking, coal/gas mines), wind/environmentally-powered energy (turbines), and hydroelectric power (dams).

"Noisy" and "unsightly" are the most accurate descriptions of the nuclear energy process.

If this helped you, I'd appreciate Brainliest! <3 TY

which gland will need to produce hormone after eating banana?

A. pituitary gland

B. thyroid

C. adrenal glands

D. Pancreas​

Answers

Answer:

thyroid

Explanation:

Right after we eat a sugary meal, the glucose levels in our blood begin to rise. Conversely, if we haven't eaten for a couple of hours our blood glucose levels begin to drop. Our body has a mechanism whereby it maintains blood glucose levels.

Why did Gregor Mendel use peas in his experiments?
Peas grow very slowly.
Pea reproduction cannot be controlled.
Peas normally produce very few offspring.
Peas have characteristics that have two forms.

Answers

Answer: Peas have characteristics that have two forms

Explanation: He chose peas because they had been used for similar studies, are easy to grow and can be sown each year. Pea flowers contain both male and female parts, called stamen and stigma, and usually self-pollinate. Self-pollination happens before the flowers open, so progeny are produced from a single plant.

Peas having characteristics that have two forms is the reason they were

used by Gregor Mendel

Who was Gregor Mendel?

He was a biologist and is regarded s the father of modern genetics. He

performed various experiments using pea plants.

The reason why the pea plants was used by him was as  result of it having

characterisitics in two forms such as smooth and wrinkled etc.

Read more about Gregor Mendel here https://brainly.com/question/1675246

pleeaasee help me its about plants and i dont know how do itttt

Answers

Petunia = perennial

Fescue grass = perennial

carrots = biennial

sweet corn = annual

tomato = annual

blueberry = perennial

cabbage = biennial

zinnia = annual

sugar maple = ??

blue spruce = annual

ur welcome xx

The guy above did a good job those are the answers

Read the article and use the information to answer the following questions.

Cystic Fibrosis

List four symptoms associated with cystic fibrosis.

Answers

Answer:

so hope it helps i think.

Explanation:

Chronic coughing.

Recurring chest colds.

Wheezing or shortness of breath.

Frequent sinus infections.

Very salty-tasting skin.

Answer: person above is correct

Explanation:

Which of the following is definitely true about the kingdom, Protista.
A. They always have a cell wall

B. They always have a nucleus

C. They are always unicellular

D. They are always heterotrophs

Answers

Answer:

B. They always have a nucleus

Explanation:

The organisms belonging to kingdom Protista are single-celled- means they are unicellular and they have a well-defined nucleus enclosed in a nuclear membrane. Hence, they are eukaryotes. So the correct option is B.

Answer:

B. They always have a nucleus

Explanation:

Protista always has a nucleus. So, option (B) is the correct answer.

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