HELP PLEASE!!!
A. Describe the difference between gradualism and punctuated equilibrium.
B. Describe the conditions under which new species may arise.
C. Explain the difference between allopatric and sympatric speciation.
D. Describe the role of prezygotic and postzygotic barriers in the process of speciation.

Answers

Answer 1

A. Both theories describe the rates of speciation. For Gradualism, changes in species is slow and gradual, occurring in small periodic changes in the gene pool, whereas for Punctuated Equilibrium, evolution occurs in spurts of relatively rapid change with long periods of non-change.

B. New species arise through a process called speciation. In speciation, an ancestral species splits into two or more descendant species that are genetically different from one another and can no longer interbreed.

C. Allopatric speciation occurs when two species are living in separate environments and therefore there is no gene flow between the populations. ... Sympatric speciation occurs when two species are living in the same environment.

D. Reproductive isolation is a mechanism that keeps species from mating with others. Prezygotic isolation prevents the fertilization of eggs while postzygotic isolation prevents the formation of fertile offspring. ... Postzygotic mechanisms include hybrid inviability, hybrid sterility and hybrid "breakdown."


Related Questions

A student is shown a slide of cells from a species of a producer
in a food web. The student observes that the cells have
chloroplasts. What conclusion about the food web is best
supported by these findings?
o
A. The producers capture energy from sunlight.
B. The food web contains many herbivores and omnivores.
C. The food web is found in a terrestrial ecosystem.
D. The producers in the web are single-celled organisms.

Answers

Answer:

the producers capture energy from sunlight

Suppose that millions of years from now Australia moves to South America. Would Australia still have the same kinds of mammals? Explain your answer.

Answers

Answer:

Which best explains why Australia has life forms that do not exist anywhere else on Earth? Australia was separated from the other landmasses by geological forces. Scientists think that dolphins and whales may have evolved from a common ancestor.

Assuming that millions of years from now Australia moves to South America. Australia would not have the same types of mammals, because with the junction of the continents new conditions would suggest for animals to evolve.

What was the evolution of continents?

Continental Drift is a theory that claims that, at one time, all the present-day continents formed just a single landmass, called Pangea. This supercontinent, thanks to the movement of the Tectonic Plates, fragmented several times until it provided the current shape of the land masses.

With this information, we can conclude that millions of years from now Australia will move to South America. Australia would not have the same types of mammals, as with the joining of the continents new conditions would suggest the evolution of animals.

Learn more about Continental Drift in brainly.com/question/903117

When plants with red flowers are crossed with plants with blue flowers, sometimes only red flowers are produced; other times either red or blue flowers are produced. Which gene is dominant?

Answers

wait what???????????????

Answer:

The colors you see in flowers come from the DNA of a plant. Genes in a plant's DNA direct cells to produce pigments of various colors. When a flower is red, for instance, it means that the cells in the petals have produced a pigment that absorbs all colors of light but red.

Explanation:

Dominant refers to the relationship between two versions of a gene. Individuals receive two versions of each gene, known as alleles, from each parent. If the alleles of a gene are different, one allele will be expressed; it is the dominant gene. The effect of the other allele, called recessive, is masked.

A $10 shirt is on sale for 25% off the price. What is the sale price of the shirt?

Answers

Yes the answer is $7.50

Please help me and no file
Explain IN YOUR OWN WORDS why cancer drugs "turn a cancer's weakness against itself."

Answers

can you explain a little more

Answer:

There are several possible reasons for chemotherapy resistance: Some of the cells that are not killed by the chemotherapy mutate (change) and become resistant to the drug. Once they multiply, there may be more resistant cells than cells that are sensitive to the chemotherapy. Gene amplification.

Hello, I'm 18 yrs, I just wanted to see the answer pls for this!

Answers

Answer:

Central diagram

Explanation:

what organelles work together to produce proteins?

A. nucleus and ribosome

B.cell membrane and nucleus

C.mitchondria and ribosomes

D.Mitchinondria and vacuole​

Answers

Answer: A

Explanation:

The nucleus provides the instructions for making the proteins (the DNA) and the ribosomes are actually where the proteins are made.

Answer:

Explanation:

Option C is the correct answer

Complete the following sentence.
The more blank structures two species have, the more closely related they may be. the more structures two species have, the more closely related they may be

Answers

Answer: Homologous

Explanation: The more Homologous structures two species have, the more closely related they may be.

Which gas is released due to photosynthesis?

A Carbon dioxide

B Oxygen

C Nitrogen

D Methance

Answers

Answer:

Oxygen

Explanation:

Plants take in Carbon dioxide and releases Oxygen

What are the three functions of the integumentary system?

Answers

Answer: protection regulation and sensation

Explanation:

Your normal heartbeat before exercise is called your ____________________.




heart rate


muscle


pre-heart rate


tissue

Answers

Answer:

Heart rate i think

Explanation:

Answer:

it should be resting heart rate, but i dont see that as an answer...

Which statements correctly describe the grana and stroma?
Select two that apply.

A. Inside the outer membranes is a gel-like fluid known as the stroma.
B. Inside the outer membranes is a gel-like fluid known as the grana.
C. Stacks of thylakoid membranes are collectively called the stroma.
D. Stacks of thylakoid membranes are collectively called grana.

Answers

Answer:

Stacks of thylakoid membranes are collectively called grana.

places where seeds are stored to help preserve biodiversity?​

Answers

Answer:

Millions of these tiny brown specks, from more than 930,000 varieties of food crops, are stored in the Global Seed Vault on Spitsbergen, part of Norway's Svalbard archipelago. It is essentially a huge safety deposit box, holding the world's largest collection of agricultural biodiversity.

Explanation:

thanks me later

UHMM I REALLY NEED HELP IM BAD AT Science

Answers

Answer:

the answer is A im 99 percent shure

What phase of the moon does this image represent?

Answers

Answer:

Waxing Quarter

Explanation:

The earth belongs to a system of gas, dust, stars, and orbiting objects known as which of the following?

Answers

Answer:

mILKY wAY gALAXY

Explanation:

Take a subject of origins or a question you have and write a minimum of 500 words as a research project. Be sure to list all references and resources as part of your bibliography. Other information can be found at a library or other reference source. (It has to be the creation theory because I go to a christian school.)

Answers

Answer:

Life on Earth began more than 3 billion years ago, evolving from the most basic of microbes into a dazzling array of complexity over time. But how did the first organisms on the only known home to life in the universe develop from the primordial soup?  One theory involved a "shocking" start. Another idea is utterly chilling. And one theory is out of this world!  Inside you'll learn just how mysterious this all is, as we reveal the different scientific theories on the origins of life on Earth.Electric sparks can generate amino acids and sugars from an atmosphere loaded with water, methane, ammonia and hydrogen, as was shown in the famous Miller-Urey experiment reported in 1953, suggesting that lightning might have helped create the key building blocks of life on Earth in its early days. Over millions of years, larger and more complex molecules could form. Although research since then has revealed the early atmosphere of Earth was actually hydrogen-poor, scientists have suggested that volcanic clouds in the early atmosphere might have held methane, ammonia and hydrogen and been filled with lightning as well. The first molecules of life might have met on clay, according to an idea elaborated by organic chemist Alexander Graham Cairns-Smith at the University of Glasgow in Scotland. These surfaces might not only have concentrated these organic compounds together, but also helped organize them into patterns much like our genes do now.  The main role of DNA is to store information on how other molecules should be arranged. Genetic sequences in DNA are essentially instructions on how amino acids should be arranged in proteins. Cairns-Smith suggests that mineral crystals in clay could have arranged organic molecules into organized patterns. After a while, organic molecules took over this job and organized themselves.

Explanation:

A climbing plant wraps around a lattice structure as it grows. This is an example of which type of tropism?

Answers

Answer: I believe it is Thigmotropism.

This is thigmotropism as it is responding to touch. Since the plant cannot support itself, it wraps around the lattice structure.

Which neurotransmitters are used for each division of the autonomic nervous system? Be sure to describe the synapse at the autonomic ganglion and at the effector. What component of the system determines if a given neurotransmitter has an excitatory or inhibitory effect on the target effector?

Answers

Answer:

The autonomic nervous system is in charge of controlling visceral effectors. Traditionally, it is described by its peripheral nervous components (ganglia, nerves and plexuses) and two divisions are distinguished: the sympathetic and the parasympathetic. Transmission of the excitatory stimulus through the synaptic cleft occurs by release of neurotransmitters; the neurotransmitters of the sympathetic and parasympathetic nervous system are mainly norepinephrine (NA) and acetylcholine (AC). The NA-secreting fibers are called adrenergic and those that secrete AC, cholinergic. All preganglionic neurons, both those of the sympathetic nervous system and those of the parasympathetic nervous system, are cholinergic. The neuron that releases the neurotransmitter is called a presynaptic neuron. The signal receptor neuron is called a postsynaptic neuron. Depending on the type of neurotransmitter released, postsynaptic neurons are either stimulated (excited) or de-stimulated (inhibited).

Explanation:

The autonomic nervous system is the part of the central and peripheral nervous system that is responsible for the regulation of the involuntary functions of the organism, the maintenance of internal homeostasis and the adaptive responses to variations in the external and internal environment  and two divisions are distinguished: the sympathetic and the parasympathetic. Acetylcholine is the preganglionic neurotransmitter of both divisions of the S.N.A. (sympathetic and parasympathetic) and also of the postganglionic neurons of the parasympathetic. The nerves at whose endings acetylcholine are released are called cholinergic. Norepinephrine is the neurotransmitter of postganglionic sympathetic neurons. The nerves into which norepinephrine is released are called adrenergic. Within the efferent sympathetic impulses, the postganglionic neurons that innervate the eccrine sweat glands and some blood vessels that supply the skeletal muscles are of the cholinergic type. Both acetylcholine and norepinephrine act on the different organs to produce the corresponding parasympathetic or sympathetic effects. The peripheral nerve endings of the sympathetic form a reticulum or plexus from which the terminal fibers come in contact with the effector cells. All the norepinephrine in peripheral tissues is found in the sympathetic endings in which it accumulates in subcellular particles analogous to the chromaffin granulations of the adrenal medulla. The release of norepinephrine at nerve endings occurs in response to action potentials that travel through nerve endings. The receptor, when stimulated by catecholamines, sets in motion a series of membrane changes that are followed by a cascade of intracellular phenomena that culminate in a measurable response. There are two classes of adrenergic receptors known as alpha and beta. These two classes are again subdivided into others that have different functions and that can be stimulated or blocked separately. Norepinephrine primarily excites alpha receptors and beta receptors to a small extent. The neurotransmitter acetylcholine is synthesized at the axonal terminal and deposited in synaptic vesicles. Acetylcholine activates two different types of receptors, called muscarinic and nicotinic receptors. Acetylcholine (AC) synthesis takes place at presynaptic termination by acetylation of choline with acetyl-coenzyme A, a reaction catalyzed by acetylcholinetransferase. The energy required for the release of a neurotransmitter is generated in the mitochondria of the presynaptic terminal. Binding of neurotransmitters to postsynaptic membrane receptors produces changes in membrane permeability. The nature of the neurotransmitter and the receptor molecule determines whether the effect produced will be one of excitation or inhibition of the postsynaptic neuron.

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Answers

Answer:

B. Repetition is when a scientist does the same experiment several times; replication is when other scientist reproduce a scientist's experiment.

Explanation:

Repetition: Repeat.

Replication: remake

Millicent encountered this organism while walking in the forest. It grows on dead trees, consuming the detritus left by other decomposers. What term best describes this organism?:
A
saprotroph

B
detritivore

C
predator

D
scavenger

MULTIPLE CHOICE

Answers

Answer:

A. Saprotroph

Explanation:

A saprotroph is described as an organism that gains nourishment from organic matter that has started to decay.

As per the situation, the organism that grows on dead trees, consuming the detritus left by another decomposer are saprotroph.

What is a saprotroph?

Saprotroph, also called saprophyte or saprobe, are organism that grazes on the nonliving organic matter known as debris at a microscopic level.

Bacteria, fungi, etc are examples of saprotrophs.

Thus, option "A" saprotroph.

To learn more about click here:

https://brainly.com/question/755458

fog is a cloud that has.

Answers

And red is a color not the word "stop"

Answer:

it's Base near the ground

Explanation:

occurs close to the earth surface

In an article about saving the whales written by a marine biologist, which word might be used by the author to make you want to help with saving the whales?

Answers

Answer:

Endangered

Explanation:

Endangered species are organisms that are at risk of extinction if deliberate efforts are not made to conserve them due to a rapid decrease in their population.

Hence, if a marine biologist writes an article about saving whales and labels them as endangered species, all efforts should be geared towards saving the animals lest they go extinct and leave a vacuum in the functioning of the ecosystem.  Every species have the critical roles they play in the functioning of the ecosystem and the extinction of any particular species represents a loss that might not be replaceable.

Answer:

endangered

i did the USAtestprep

4. There are three codons that signal the end of synthesis, these are called STOP codons.
What are the three stop codons?

Answers

Answer:

UAG, UAA, and UGA are the three STOP codons.

Explanation:

EXTRA POINTSS someonee please help me answer this

Answers

Claim- point A has the greatest potential energy

Evidence- point A is at the top of the rollercoaster, at a steady point

Reasoning- higher objects with further to fall have the greatest potential energy

Conclusion- Point A has the greatest potential energy because of its high position from the ground, and it has the biggest stored up energy waiting to fall.

Answer: C

Explanation: At that point, you have all of the momentum from B, and it is RIGHT at that point before it starts to lose energy. It has all of the built up momentum that started at A, and continued at B, and to continued to increase until C.

Anyone know this? Not sure if my answer is right

Answers

Your answer is right

Answer:

I'm sure you right.

C.) Photosynthesis.

Explanation:

I checked the chemical equation as well as the diagram, and it looks accurate.

The chemical equation for photosynthesis is:

6CO2+6H2O → C6H12O6+6O2.

So your answer is correct.

In plants, photosynthesis is used to convert light energy from sunlight into chemical energy (glucose).

Carbon dioxide, water, and light are used to make glucose and oxygen.

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Good luck foe.

Lb

Which three terms relate to sexual reproduction but not to asexual reproduction?
A. Sperm
B. Mitosis
C. Gametes
D. Meiosis

Answers

Answer:

I believe its A, C, and D

Explanation:


Most bacteria are surrounded by a rigid protective structure called the _____.
•cell wall
•cell membrane
•flagellum
•protein coat

Answers

Answer:

Most bacteria are surrounded by a rigid protective structure called the cell wall.

Using homologous structures and any other information (from notes, activities, etc),
explain your opinion on the THEORY OF EVOLUTION in 8 sentences. Be sure to cite
evidence (supporting details) for your ideas (EVALUATION RI 8.8).

Answers

evolution is fundamentally unpredictable.the theory of evolution as it is used here refers to "macroevolution'a theory is meant to both explain and predict;the theory of evolution only explains .the theory of evolution is not a theory and it is suggested calling it a working hypothesis:the working hypothesis of evolution

The shark and remora fish have a __________________ relationship. The remora fish benefits by attaching itself to a shark and eating scraps and pieces of fish that the shark does not eat. The shark is not harmed and does not benefit from the remora fish.

Answers

Answer:

commensalism

Explanation:

one benefits while the other does not

Answer:

commensalism

Explanation:

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