Answer:
A yellow lizard population living on an island with no predatorsA hawk was introduced to the habitat and starts preying on the yellow lizard because it is easier to see from the air Some of the lizards mutate their color from yellow to greyish brown so they can camouflageYellow individuals keep being hunted, while brown individuals get to survive The following generations of lizards will have a higher proportion of greyish brown individuals and just a few yellow individuals. Eventually, almost all of the lizards will be greyish brown individuals.Explanation:
The scenario is the following.
A population of yellow lizards lives on an island where there is no natural predator. Males of the species use the yellow color to attract females in reproductive seasons. The brighter the males are, the better their genetic quality is. Females are also yellow, but not as bright as males.
A new hawk species was introduced into the island to control some farm pests. But this hawk species prefer to feed on the lizards. The yellow color of these animals contrasts with the dark background and can be easily seen from the air. So the lizard population suffers from significant predation affecting its size sharply.
Some of the lizards then suffer from a mutation and change their color from yellow to greyish brown, which turns to be better to camouflage on the rocks and get to survive. Individuals with greyish brown color get to reproduce at a higher rate than yellow individuals, who keep being hunted by the hawk.
Eventually, after many generations, the yellow individuals decrease to near zero in the population, while greyish brown individuals increase significantly, with males still being brighter than females.
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Natural selection is an evolutive force that can act favoring an allele or against it, according to how it affects the fitness of individuals. Natural selection selects beneficial alleles and increases their frequency in the population.
When many organisms in a population sharing the same trait die, it is because they did not have good fitness, so they were not adapted to the environment and its pressures. The alleles coding for that trait were not good for the fitness of the animals, so they do not get to survive.
These individuals die before reproducing, so they could not transfer their genetic charge to the following generation. Eventually, the alleles coding for the trait will decrease in the population, probably near zero. Natural selection is acting against this phenotype. Other alleles will be beneficiated, and their frequency in the population will increase.
This change in alleles frequency is what we call adaptation.
Natural selection results in adaptation, which means the increase of the aptitude phenotype. Aptitude is the contribution of each genotype to the next generation.
In many cases, adaptations can be correlated to environmental factors or selective pressures applied by other organisms or habitats.
Let us remember that a mutation is a change or alteration in DNI sequences that introduce new variants. Many of these are eliminated, but some of them might succeed and be incorporated into each individual. These mutations are the ones that have been selected by natural selection.
So, in the exposed example, we are focussing on the lizards population.
• The selective pressure or modeling environmental factor is predation by the introduced hawk.
• The lizards´ response to predation is the survival of only those that carry mutations ⇒ greyish brown color
• Natural selection benefits these mutations.
• Greyish brown lizards survive and increase their fitness.
A degraded ecosystem is replaced with a different but productive ecosystem type, one that might even include some nonnative species. For example, a degraded forest might be replaced with a productive pasture.a. passive restoration b. remediation c. partial restoration d. rehabilitation e. complete restoration
Answer:
d. rehabilitation
Explanation:
Technology-associated rehabilitation is an ecological practice that allows a degraded area to be restored, rehabilitating all its degraded habitats. However, this restoration is not done naturally, but is caused by human intervention, which can cultivate the entire plant population in the area, even adding non-native species, which are selected to leave the productive area, but ecologically harmonious.
predators are... a. primary producers b. primary consumers c. secondary consumers
Answer:
Primary consumers
They eat the majority of prey
You are carrying a case of 24 bottles of water up the stairs to your third-story apartment. What type of contraction are the muscles in your arms experiencing
Answer:
Concentric contraction.
Explanation:
Concentric contraction is a type of contraction that the muscles in arms experiencing when an individual lifting 24 bottles of water up the stairs. A concentric contraction is a type of muscle activation that creates tension on your muscle as it shortens. As your muscle shortens, it produces enough force to move an object in the upward direction. In weight training we can easily see concentric movement.
do both plant cells and prokaryotic cells have 70S ribosomes
Which of the cardiac cell characteristics describes the
ability to initiate an electrical impulse?
Answer:
The correct answer is: automaticity.
Explanation:
Cardiac muscle has several properties. These properties are: automaticity (given by the pacemaker cells), conductivity (meaning that each cardiac cell can transmit the electrical impulse to the next cardiac cells), contractility (like other types of muscles, cardiac muscle cells can contract), and irritability (each cell can contract on its own without the external stimuli).
Cardiac pacemaker cells are the ones with the capacity to initiate the electrical impulse by creating rhythmic impulses called action potentials, and thus directly regulating heart rate.
Pacemaker cells are located in the sinoatrial (SA) node, in the upper portion of the right atrial wall. In these cells, depolarization of the cardiac muscle begins, and the electrical impulse generated by it is transmitted to the atrioventricular (AV) node, the His bundle and then the Purkinje fibers - this order of events is necessary for the correct contraction of the heart to occur. All of these structures are part of the Conduction System of the heart.
If 622 water molecules were removed during the synthesis of a specific polysaccharide, how many monomers were joined together to make this molecule? need help please and thank you
Answer:
623 monomers
Explanation:
In a dehydration synthesis reaction, one water molecule is removed for every bond that is created between 2 monomers.
Linking 3 monomers together would remove 2 water molecules.
Following this pattern, the number of water molecules removed will always be one less than the number of monomers that were joined together.
So, if 622 water molecules were removed, then 623 monomers were joined together.
The answer is 623 monomers.
Please help!! Need the Correct Answer ASAP!!
Which statement is true?
A.Peat is a fossil fuel because rewetting it takes only 3–5 years.
B.Peat is a fossil fuel because the total time for restoration is lengthy.
C.Peat is not a fossil fuel because it has biologic origins, making it a biofuel.
D.Peat is not a fossil fuel because humans can promote the replenishment of peat.
Answer:
c) peat is not a fossil fuel because it has biologic origins, making it biofuel
Explanation:
Peat is soil/ turf
I need help asap
I need help asap
Answer:
c
Explanation:
i dont care
In 1985 a biologist counted 750 pine trees in a 250 hectare forest. Using similar counting techniques, the biologist counted 1,250 pine trees in 1990 and 1,500 pines in 1995.
What was the average change of the size of the population from 1985 to 1995?
What was the density of pine trees each year that they were counted?
What was the average change of density from 1985 to 1995?
Answer:
Suppose that we have a given function f(x)
The average rate of change of the function between two values x₁ and x₂ is given by:
[tex]r = \frac{f(x_2) - f(x_1)}{x_2 - x_1}[/tex]
a) We want to find the average (rate) of change on the size of population from 1985 to 1995.
We have that:
f(1985) = 750
f(1995) = 1500
Then we have:
[tex]r = \frac{1500 - 750}{1995 - 1985} = 750/10 = 75[/tex]
This means that the population of trees increases, in average, at a rate of 75 trees per year.
b) What is the density of trees each year that they were counted?
This will be equal to the quotient between the number of trees and the area.
1985: number of trees = 750 pines
area = 250 ha
Then the density is:
D(1985) = (750 pines)/(250 ha) = 3 pines/ha
So 1985, there were 3 pines per hectare.
1990: number of trees = 1250 pines
area = 250 ha
Then the density is:
D(1990) = (1250 pines)/(250 ha) = 5 pines/ha
1995: number of trees = 1500 pines
area = 250 ha
The density is:
D(1995) = (1500 pines)/(250 ha) = 6 pines/ha
3) now we want to get the average change between 1985 and 1995 in the density, this will be:
[tex]r = \frac{D(1995) - D(1885)}{1995 - 1985} = \frac{6 pines/ha - 3pines/ha}{10} = 0.3 pines/ha[/tex]
So, on average, each year the number of pines per hectare increases by 0.3
Which of the following is a unifying characteristic of life?
Answer:
where is option I can't see
D - Telophase
C - Anaphase
A - Prophase
B - Metaphase
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Choose the correct description for each phase of mitosis.
Answer:
A-B-C-D
Explanation:
PROPHASE; 1. chromosomes become thicker
2. nuclear membrane disintegrates
3. centrosome divide to form centrioles
4. centrioles move to the opposite polls of the cell
METAPHASE; 1. chromosomes get arranged at the equator
2. centrioles produce spindle fibre that attach to the middle of the chromosomes
ANAPHASE; 1. shortest stage of mitosis
2. spindles will pull apart each chromosomes to form chromatids
TELLOPHASE; 1. each chromatid moves to opposite polls of the cell
2. nuclear membrane appears around both of them
3. the centrioles sill stop producing spindles
4. centrosomes will then form again
cytokinesis then divides by the cleavage furrow to form the two daughter cells
¿Qué nombres reciben los tejidos que dan
origen a los tejidos adultos de las plantas?
a. Tejidos diferenciados
b. Tejidos indiferenciados (meristemos)
c. Tejidos vegetales
Answer:
D
Explanation:
If a diploid cell has 20 chromosomes, how many sister chromatids will be present
during PROPHASE of MITOSIS?
Answer:
92 chromatids
Explanation:
During phosphate, the nuclear envelope of the cell (which is where the 92 chromatids are contained) begins to break down. The centrioles, which are the only present in animal cells, separate and each moves to an opposite end of the cell
Cystic fibrosis is most common in individuals of Northern European descent, affecting 1 in 3200 newborns. Assuming that these alleles are at Hardy-Weinberg equilibrium, what is the frequency of the disease-causing CFTR alleles in this population
Answer:
0.0177
Explanation:
Cystic fibrosis is an autosomal recessive disease, thereby an individual must have both copies of the CFTR mutant alleles to have this disease. The Hardy-Weinberg equilibrium states that p² + 2pq + q² = 1, where p² represents the frequency of the homo-zygous dominant genotype (normal phenotype), q² represents the frequency of the homo-zygous recessive genotype (cystic fibrosis phenotype), and 2pq represents the frequency of the heterozygous genotype (individuals that carry one copy of the CFTR mutant allele). Moreover, under Hardy-Weinberg equilibrium, the sum of the dominant 'p' allele frequency and the recessive 'q' allele frequency is equal to 1. In this case, we can observe that the frequency of the homo-zygous recessive condition for cystic fibrosis (q²) is 1/3200. In consequence, the frequency of the recessive allele for cystic fibrosis can be calculated as follows:
1/3200 = q² (have two CFTR mutant alleles) >>
q = √ (1/3200) = 1/56.57 >>
- Frequency of the CFTR allele q = 1/56.57 = 0.0177
- Frequency of the dominant 'normal' allele p = 1 - q = 1 - 0.0177 = 0.9823
The suprachiasmatic nuclei enable the nervous system to respond to daily light/dark alterations through their stimulation of
Answer:
The suprachiasmatic nuclei enable the nervous system to respond to daily light/dark alterations through their stimulation of melatonin.
Explanation:
Melatonin is a hormone produced naturally by the body. Its function is to regulate the body's circadian cycle. This hormone is stimulated and begins to act by changing between a light environment and a dark environment. This stimulation interacts with the suprachiasmatic nuclei making the nervous system understand this change and luminosity of the environment and respond to the action of melatonin.
How do scientists create models of past and future climate?
Answer:
To understand how our world is evolving, scientists use computer programs called climate models to forecast future climate. Climate models function in the same way that a computer lab does. Climate models are computer programs that scientists use to analyze how our world is changing.
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hope it helps...
have a great day!!
A particular cross gives a modified dihybrid ratio of 9:7. What phenotypic ratio would you expect in a testcross of the fully heterozygous F1 crossed with the fully recessive type
Answer:
3:1
Explanation:
Due to technical problems, you will find the complete explanation in the attached files.
Two species of closely related frogs are found in the same pond high in the Andes of South America. Both species only have teeth on the top jaw. One has small teeth for holding small live prey prior to swallowing. The other species has very large sharp teeth for injuring and killing large prey prior to biting off pieces of flesh for consumption. The above is an example of:
Complete question:
Two species of closely related frogs are found in the same pond high in the Andes of South America. Both species only have teeth on the top jaw. One has small teeth for holding small live prey prior to swallowing. The other species has very large sharp teeth for injuring and killing large prey prior to biting off pieces of flesh for consumption. The above is an example of:
Directional selectionAnalogous structuresCharacter displacementHybridization Vestigial structuresAnswer:
Character displacementExplanation:
Competition is an ecological and evolutive process very common in nature. Competition might be intra- or interspecific. Competition between different species in a community or ecosystem might be due to the same resource use, or the same territory, shelter, etcetera. When a resource is useful for two or more species, and limited, they compete to gain it.
The principle of competitive exclusion states that different species with the same requirements sharing the niche can not coexist indefinitely based on the same limited resource. When two competing species coexist, this is because of niche partitioning or niche differentiation.
Differentiation of effective niche is closely related to character displacement.
Character displacement is the result of interspecific competition, in which two or more species that live in the same habitat manage to avoid competition by developing different traits. Morphological divergence, or any adaptative trait development, fixated genetically, is the product of niche segregation. Species tend to differentiate morphologically in the presence of strong competitors. Traits divergence favors coexistence in the same place.
In the exposed example, both species live in the same pond. But to avoid competition and competitive exclusion, species developed different teeth sizes to feed on different prey items.
Which isn’t an example of a matrix in which organisms may become fossilized
Answer:
where's the options for this question?
:/
there is no option?? ?
Which of these is a benefit of fish farming?
A. It can deplete native fish populations
B. It can restock lakes depleted by recreational fishing
C. It can pollute natural bodies of water
D. It can pass diseases to native fish populations
Answer:
The answer to this would be B
Explanation:
B:It can restock lakes depleted by recreational fishing
18. Why are enzymes important to cells?
о
They provide structural support.
о
They form the two layers of membranes.
They store large quantities of energy.
о
They help bring about chemical reactions
Answer:
An enzyme is a type of protein found within a cell. Enzymes create chemical reactions in the body. They actually speed up the rate of a chemical reaction to help support life.
A muscle that is stimulated so frequently that the relaxation phase is eliminated is said to exhibit _______. Question 13 options: tetanus recruitment treppe wave summation
Answer:
tetanus
Explanation:
Tetanus causes a strong tonic contraction in skeletal muscles. This triggers a series of intermittent, progressive, and extremely painful muscle spasms. Tetanus is presented by patients who have stimulated a muscle too often, without allowing a moment of rest.
Try this for yourself. Suppose you want to estimate the number of field mice in a small field. One day you capture 500 mice, mark all of them and release them. The next week you capture 200 mice of which 40 were marked by you yesterday. What is your estimate of the population size?
Answer:
The approximate size of the field mice population is 2500 individuals.
Explanation:
There are different methods to study population density. There are direct methods and indirect methods. Among these last ones, we might find the "Mark-Recapture technique".
The Mark-Recapture technique assumes that the population is closed, during the sampling season there is no mortality nor natality, marks in the individual last the whole sampling season, and these do not affect the marked individual or their behavior. These marked individuals are randomly distributed in the population, and all the individuals have the same probability of being sampled.
The method consists of capturing a sample of individuals belonging to the population under study, in this case, the field mice population. After capturing the individuals, the researcher marks them and release them again. The third step is to sample again, capture a new amount of individuals, and count how many of them are marked. These marked individuals belong to the first sample. We can calculate the population size by using the Lincoln Index or any other index.
The Lincolns Index states that to obtain the population size, the research must follow the following procedure:
1) Take an initial sample with n1 number of individuals
2) Mark all the sampled individuals and release them
3) Take a second sample with n2 number of individuals
4) Count the number of marked individuals m
To estimate the total number of individuals in this population, N, the following equation must be considered:
N = (n1 x n2)/m
In the exposed example, this is:
• n1= 500 individuals in the first sample
• n2= 200 individuals in the second sample
• m= 40 individuals in the second sample that were previously marked
as they were part of the first sample
N = (n1 x n2)/m = (500 x 200) / 40 = 2500 individuals
The approximate size of the field mice population is 2500 individuals.
What methods help control pollution source
Practicing conservation tillage traps contaminants from Runoff water. Practicing conservation tillage helps prevent BLANK
A. Air pollution
B. Water pollution
C. Soil erosion
Where does crude oil come from?
A. Bauxite reserves
B. Ancient sea life
C. Volcanic magma
D. Ancient plants
Answer:
B. Ancient sea life
explain what it means to view something from a frae of reference. provide an example that illustrate your explanation.
Answer:
ex. where you are standing now
a perspective that one uses to determine if an object is moving.
Explanation:
in physics, a frame of reference, or reference frame, is a perspective that one uses to determine if an object is moving. ... For example, when you see a ball roll down a street, you can tell the ball is moving because the frame of reference is the streets, whatever may be on the side of the roads, or the Earth.
wikipedia
oxygen is carried by blood to all the cells of body in the form of ___________
Answer:
Oxygen is carried by blood to all the cells of the body in the form of haemoglobin.
Explanation:
Oxygen is carried in the blood in two forms:
(1) dissolved in plasma and red blood cells water (about 2% of the total)
(2) reversibly bound to haemoglobin (about 98% of the total).
Haemoglobin is a protein in the red blood cells and carries oxygen around our bodies. At the same time, carbon dioxide that is dissolved in the blood comes out of the capillaries back into the air sacs, ready to be breathed out.
In pea plants, flowers are either white or purple: the purple color is produced by pigments called anthocyanins. The production of anthocyanins is a two-step process: the first step is controlled by the C gene and the second by the P gene. Both genes must produce functional proteins for anthocyanin to be produced. This is an example of:
Answer:
This is an example of gene translation.
Explanation:
Gene translation refers to the genetic process where a set of genes is used to create amino acids that will be responsible for creating a protein needed to perform some function or characteristic of the organism. In the question above, we can see that anthocyanin, responsible for the pigment of flowers, is created through the work of proteins that are created from gebes C and P. This is an example of gene translation, as it presents the formation of proteins regulated by genes.
characteristics of Pisces
Answer:
Pisces are known as amazingly imaginative, creative, empathetic, and kind, they can also be overly sentimental, impressionable, and closed off.
Explanation:
Hope this helps!
In a test cross, a pure-breeding plant is crossed with a plant suspected to be heterozygous (Aa). What is the genotype of the pure-breeding plant?
Answer:
aa
Explanation:
In genetics, a test cross is a cross performed to determine the unknown genotype of a phenotypically dominant organism. The test cross is done by crossing the unknown genotype with a homzygous recessive organism. The result of this cross tell us whether the unknown genotype is heterozygous or homzygous dominant.
According to this question, a test cross was conducted involving a pure breeding plant with a plant suspected to be heterozygous (Aa). Based on the explanation of a test cross above, the genotype of the pure-breeding plant will be "aa". Note; it must be recessive.
