Over the past 60 years, many amphibian species have experienced significant population declines and some species have become extinct. Scientists suspected that local human activities such as the destruction of wetlands, regional pollution, and deforestation were the main reasons for these losses. However, research over the past 20 years reveals significant amphibian population declines in protected areas of the world, such as nature preserves and parks. These global declines suggest widespread problems including increased ultraviolet radiation, acid rain, and disease. In Switzerland, for example, 14 of the 20 native amphibian species are threatened with extinction. Some biologists urge the collection of the few remaining individuals of some of the most threatened amphibian species, to preserve them if they become extinct in the wild. If such captive breeding programs could produce thousands of individuals from just a few of the remaining survivors, the species will still be threatened because of ______.

Answers

Answer 1

Answer:

a bottleneck effect

Explanation:

Genetic drift refers to the change in the allele frequencies in a population due to chance (random) events. The bottleneck effect, also known as population bottleneck, can be defined as a severe case of genetic drift caused by a drastic reduction in the population size. The bottleneck effect is well known to cause the loss of important genetic variation since alleles that were present in the original population are lost, thereby limiting its genetic diversity. One of the most common causes that may lead to a population bottleneck in a natural population is environmental disasters (e.g., earthquakes, floods, etc).


Related Questions

Which parts of the biodome contain carbon?

Answers

Carbon is stored in the lithosphere in both inorganic and organic forms. Inorganic deposits of carbon in the lithosphere include fossil fuels like coal, oil, and natural gas, oil shale, and carbonate based sedimentary deposits like limestone.


Hood this helps

The principle that the geologic processes that we see today have occurred throughout earths history is called

Answers

the bible jot jehova witness that’s the only i was taught

The number of mosquitoes at the beginning of the summer was 4,000. There were 500 born and 550 died. What is the growth rate of the mosquitos population? Looking at the birth and deaths does your growth rate makes sense. Explain why or why not.


Answer the following with the growth rate formula: r=(b-d)/N


Please help quick 50 points

Answers

Answer:

-50

Explanation:

500-550

Que son los combutibles fósiles y cuales son los que dañan más al medio ambiente?

Answers

Answer:

Mining, drilling, and burning dirty energy are harming the environment and our health. Here’s everything you need to know about fossil fuels, and why we need to embrace a clean energy future.

if you don't know English u can translate

Which phrase is the best definition of matter? A. The smallest piece of a chemical compound that retains the properties of the compound B. A substance that cannot be divided into smaller pieces C. Something that occupies a volume of space and also has mass D. A substance that can change in both volume and shape SUBMIT​

Answers

Answer:

c

Explanation:

because matter is any substance that has mass and occupies space

Review the chart, which shows the population sizes of three African animals in 1990 and in 2000.

Population Estimates of Animals in Africa in 1990 and in 2000

1990
2000
Lions
100,000
47,000
Cheetahs
50,000
7,500
Zebras
15,000
2,500

Which explanation is best supported by the numbers in the chart?

Answers

Answer:

Population of lions are more than cheetahs and zebras.

Explanation:

The chart provides information about the population sizes of Lions, Cheetah and Zebras. According to this information, population of lions is the greatest as compared to Cheetah and Zebras. This is due to suitable conditions for the lions such as food and shelter etc in that jungle of Africa as well as strong competitor and its aggressive behaviour make them successfully survive and increase its population in the jungle.

the only phylum that shows active flight in invertebrates is
coelenterata
arthropoda
mollusca
echinodermata​

Answers

Answer:

It would be arthropoda

Explanation:

Insects and arthropods are the only invertebrates able to fly since insects are not a part of your list arthropoda would be the answer. I hope this helps and if you can give me brainliest? :)

44. A food handler does NOT need to worry about time and temperature control when handling which food?
Steamed rice
Cooked beans
Grilled steak
Warmed tortillas
QUESTIONZANSY

Answers

Steamed rice or beans.

AYUDA ES PARA HOY es de Ciencias Naturales ¿Por que a veces podemos ver la Luna de día , a veces , lo podemos ver de noche y a veces , no lo podemos ver?

Answers

Answer:

Porque contigo yo ya escogi?

Ahora mi corazon ta supri

Bien simple lang iyo ta pidi

Era cinti tu el cosa yo ya cinti.

Explanation:

.;(

What kind of symmetry does the human body plan show? Explain what this means.

Answers

The last type of symmetry is the bilateral symmetry. Bilateral symmetry is when the body plan can be divided along a plane that splits the animal's body into right and left sides that are mirror images of each other. Let's look at this type of symmetry a little more.

Fatty acids are a component of what type of macromolecule?

Answers

Answer:

Lipids

Explanation:

read textbook

Fatty acids are a component of lipids macromolecules.

Fatty acids and lipids

Fatty acids are a component of lipids. Lipids are a diverse group of macromolecules that include fats, oils, phospholipids, and sterols. Fatty acids are the building blocks of lipids.

They are long hydrocarbon chains with a carboxyl group at one end. Fatty acids can be saturated (no double bonds) or unsaturated (one or more double bonds).

When combined with glycerol, fatty acids form triglycerides, the most common type of lipid used for energy storage in organisms.

More on fatty acids can be found here: https://brainly.com/question/31752492

#SPJ6

What is the function of the organelles that are labeled F?

Answers

The organelle labeled 'F' in the given diagram is Endoplasmic reticulum. The main function ER is to move proteins and other substances through the

Why do sex-linked traits follow different patterns of inheritance than other
traits?

Answers

It is because the males are heterozygous in terms of sex chromosome. They carry one copy of the X chromosome and one copy of the Y chromosome. So, only a single copy of allele is enough to produce the phenotype.

2) Cartilage is not found in
a. Nose
C. Bones
b. Adipose tissue
d. Phosphorus and potassium​

Answers

d

Phosphorus and potassium do not have any cartilage

How much has the rate of surface temperature been in the last 50 years?​

Answers

Answer:

The global average surface temperature rose to  0.6 to 0.9 degrees Celsius ((1.1 to 1.6° F)) between 1906 and 2005, and the rate of temperature increase has nearly doubled in the last 50 years!

Which definition is the best for “semipermeable membrane

Answers

Answer: A semi-permeable membrane is that which only allows certain

               substances to pass through.

Answer: A semipermeable membrane is a layer that only certain molecules can pass through. Semipermeable membranes can be both biological and artificial. Artificial semipermeable membranes include a variety of material designed for the purposes of filtration, such as those used in reverse osmosis, which only allow water to pass. The biological membranes of cells are created by two sheets of phospholipid, which contain a lipid tail attached to a polar head. The tail regions of each sheet cluster together, while the heads of the molecules point outward. The polar heads point both outward toward the environment of the cell and inward toward the cytosol. In this way, a hydrophobic region of lipid tails separates the two bodies of solution. This can be seen in the image below.

Explanation: sorry if its too much wording i tried to shorten it as much as possible

help me to do this please please​

Answers

Answer:

HELP MEE TOOOOOOO

Explanation:

Digestion
alimentary canal
milk teeth
trachea
peristalic movement
villi
rumen
caecum
liver
salivary amylase
MARK ME BRAINLIEST PLEASE

The cells of a pineapple plant have 50 chromosomes in their nuclei. How many chromosomes are there in the male nucleus in a pineapple pollen grain?

Answers

Answer:

25 chromosomes

Explanation:

There are two principal types of cells in the organism: Somatic diploid cells (2n) that reproduce by the process of mitosis, and germ cells that are diploid reproductive cells in charge of gamete production. Germ cells divide by mitosis and meiosis. Through the process of mitosis, they originate more sexual cells, but through the process of meiosis, they give place to haploid gametes, called sperm and egg cells, through the gametogenesis process.  

Gametes´destiny is to merge during fecundation, and a new diploid cell called zygote emerges through fertilization. The zygote is a complete cell and suffers successive mitosis to form the new organism.  

Meiosis produces four daughter haploid cells (n) from a diploid germ cell (2n). Each daughter cell is haploid because they have half the number of chromosomes of the original one.

So, in the exposed example

"...cells of a pineapple plant have 50 chromosomes in their nuclei..."

These might be diploid somatic or germ cells. The number of chromosomes, 2n = 50.

Germ cells in plants suffer meiosis and produce gametes.

Gametes of plants are ovocell and pollen grains. Ovocell is the feminine gamete, while the pollen grain is the masculine gamete.

The pollen grain is haploid and its number of chromosomes n = 25.

Which of these is not a type of muscle tissue?
a smooth
b. rough
C.skeletal
D. cardiac

Answers

Answer:

a

Explanation:

BEST ANSWER IS

ccccccccccccc. skeletal

HOPE I HELP

MARK ME BRAINLIST

:)

Which of the following pairs correctly matches the type of cell division with
the type of cell produced in this stage?
A) Egg Cell and Mitosis
B) Skin Cell and Meiosis
C) Zygote and Cytokinesis
D) Gamete and Meiosis

Answers

Answer:

c

Explanation:

its my lucky letter

Which is most likely to help an introduced species become invasive?

Answers

No predators, same niche as other animals in the habitat

Multiple Choice
Re-growing a forest will:

cause desertification in surrounding areas due to the trees' high water demands,

increase water run-off.
lead to eutrophication of nearby lakes,

reduce water run-off.

Answers

Answer: Reduce water runoff

identity two excretory products produced by plants​

Answers

Answer:

Carbon dioxide, excess water produced during respiration and nitrogenous compounds produced during protein metabolism are the major excretory products in plants. Plants produce two gaseous waste products i.e. oxygen during photosynthesis and carbon dioxide during respiration.

how does secondary succession differ from primary succession? it begins on bare rock or land, it begins where no plants have grown, lichens and mosses form soil first, soil nutrients are already in place

Answers

in georgia or in the crib

Answer:

In primary succession, newly exposed or newly formed rock is colonized by living things for the first time. In secondary succession, an area that was previously occupied by living things is disturbed, then re-colonized following the disturbance.

¿consideras justificado el estudio de la luz en cuanto a su aplicación en las distintas áreas de la medicina y la ciencia?

Answers

Answer:

Si.

Explicación:

Sí, considero que el estudio de la luz está justificado en cuanto a su aplicación en las distintas áreas de la medicina y la ciencia. El estudio de la luz nos permite tratar muchas enfermedades así como también se utiliza en muchos experimentos científicos. Podemos utilizar la luz en diferentes tipos de instrumentos y máquinas que se pueden utilizar en el diagnóstico de enfermedades y luego tratar la enfermedad en consecuencia.

36. Mitosis requires the chromosome to be replicated into______ copies.
a. 2
b. 6
c. 1

Answers

Answer:

Option a. "2"

Explanation:

Answer:

Mitosis requires the chromosome to be replicated into 2 copies.

option a is the answer

Explanation:

The cell separates the copied chromosomes to form two full sets (mitosis) and the cell divides into two new cells (cytokinesis). The period between cell divisions is known as 'interphase'.The genome is composed of a number of chromosomes—complexes of tightly coiled DNA that contain genetic information vital for proper cell function. Because each resultant daughter cell should be genetically identical to the parent cell, the parent cell must make a copy of each chromosome before mitosis

PLZZZZ HELPP MEE ANYONE!!!!

Answers

Answer:

The answer is the top one, C

Explanation:

"Land degradation is a process in which the value of the biophysical environment is affected by a combination of human-induced processes acting upon the land. It is viewed as any change or disturbance to the land perceived to be deleterious or undesirable."

Answer:

Land Degradation

Explanation:

because the specific defenition is "Land degradation is a process in which the value of the biophysical environment is affected by a combination of human-induced processes acting upon the land" and it is more relevant than the other defenitions.

Can someone help me with this for a brainly?

Answers

Reproduction is the second ability.

The illustration below shows the steps of meiosis
What is the step that is labeled D?

Answers

Answer:

Anaphase

Explanation:

Answer: Metaphase l

Explanation: Homologous chromosomes line up in double file

PLAY
9
Organelles are structures within the cell that perform important functions. Which of the following correctly matches
organelle with its relationship to the whole cell?
mitochondria - provides the instructions for making proteins
B nucleus - provides protection to the outside of the cell
chloroplasts - trap light energy and change it into food for the cell
cell membrane - changes the energy the cell gets from food into a form the cell can use lo

Answers

Answer:

Chloroplasts trap light energy and chnage it into food for the cell

Explanation:

In the chloroplasts is where photosynthesis occurs. Photosynthesis is the process by which plants make their own food by using carbon dioxide water and sunlight. The chlorplast traps the energy from the sunlight and then the reaction between the carbon dioxide and water can occur

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