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2 years ago

What is the habitat of the starfish and what does it eat

1 answer:

7 0

Starfish, or more accurately sea stars, fill a niche as predator and prey in marine ecosystems close to shore. With more than 18,000 species in the world, they range from the tropics to the Pacific Northwest and further north. They can grow larger than a foot across and can have as many as 40 arms. While sea stars are known for their ability to regrow lost arms, they have an unusual digestive system, too.

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otez555 [7]

The answer is C. The axial tilt can affect the temperature and daylight.

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3 years ago

F1 is the symbol for...?

guajiro [1.7K]

Answer:

F1 and F2 Generations

The offspring of the P generation are called the F1 (for filial, or “offspring”) generation.

3 0

3 years ago

Why do researchers need a lot of data to monitor a species population?

Yuliya22 [10]

Answer:

Researchers need a lot of data to monitor a species population because the environment is very diverse in types of species found at different places .

What happens to one part of it could affect the population of other animals, humans, and may also effect the ecosystem of that certain environmental region .

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2 years ago

How did the frequency of stimulation affect the amount of force generated by the isolated skeletal muscle when the frequency of

Alexxandr [17]

Answer:

When the frequency of stimulation of a muscle increases -without it having the opportunity to relax- a process called summation (addition) occurs, promoting an increase in the generation of force in the isolated skeletal muscle.

Explanation:

Summation is a phenomenon that occurs as a consequence of the arrival of successive stimuli that produce the contraction of the skeletal muscle before it achieves its partial or total relaxation, between subsequent stimuli.

When the summation occurs in the muscle, the force generated on it increases its magnitude proportionally to the number of stimuli received, maintaining the muscle contraction in time.

Tetany is the prolonged contraction of a muscle in an abnormal way, by the summation of stimuli received , as some bacterial toxins can produce. The summation can be temporary -when multiple stimuli reach the muscle in a determined time- or spatial, when the amount of stimuli activates a greater amount of motor units.

Learn more:

Spatial summation in a post synaptic neuron brainly.com/question/9632682

3 0

3 years ago

4) A homozygous groucho fly ( gro, bristles clumped above the eyes) is crossed with a homozygous rough fly (ro, eye abnormality)

docker41 [41]

Answer and Explanation:

A homozygous groucho fly ( gro, bristles clumped above the eyes) is crossed with a homozygous rough fly (ro, eye abnormality).

The F1 females are testcrossed, producing these offspring: groucho 518 rough 471 groucho, rough 6 wild-type 5 1000 a) What is the linkage distance between the two genes? B) Plot the genes on a map c) If the genes were unlinked and the F1 females were mated with the F1 males, what would be the offspring in the F2 generation?

1st cross:

Parental) grogro ro+ro+ x gro+gro+ roro

F1) gro+gro ro+ro

2nd cross:

Parental) gro+gro ro+ro x grogro roro

Gametes) gro+ro+ gro ro

gro+ro gro ro

gro ro+ gro ro

gro ro gro ro

Punnet square)

gro+ro+ gro+ro gro ro+ gro ro

gro ro gro+gro ro+ro gro+gro roro grogro ro+ro grogro roro

F2)

0.518 grogro ro+ro (518 individuals)

0.471 gro+gro roro (471 individuals)

0.006 grogro roro (6 individuals)

0.005 gro+gro ro+ro (5 individuals)

Total number of individuals 1000

Note: These frequencies were calculated dividing the number of individuals belonging to each genotype by the total number of individuals in the F2.

To know if two genes are linked, we must observe the progeny distribution. If individuals, whos genes assort independently, are test crossed, they produce a progeny with equal phenotypic frequencies 1:1:1:1. If we observe a different distribution, that is that phenotypes appear in different proportions, we can assume that genes are linked in the double heterozygote parent.

In the exposed example we might verify which are the recombinant gametes produced by the F1 di-hybrid, and we can recognize them by looking at the phenotypes with lower frequencies in the progeny.

By performing this cross we know that the phenotypes with lower frequencies in the progeny are groucho, rough and wild-type. So the recombinant gametes are gro+ro+ and gro ro, while the parental gametes are gro+ro and gro ro+.

So, the genotype, in linked gene format, of the double heterozygote individual in the F1 is gro+ro/gro ro+.

To calculate the recombination frequency we will make use of the next formula: P = Recombinant number / Total of individuals. The genetic distance will result from multiplying that frequency by 100 and expressing it in map units (MU). One centiMorgan (cM) equals one map unit (MU).

The map unit is the distance between the pair of genes for which one of every 100 meiotic products results in a recombinant product.

The recombination frequency is:

P = Recombinant number / Total of individuals

P = 6 + 5 / 1000

P = 11 / 1000

P = 0.011

The genetic distance between genes, is 0.011 x 100= 1.1 MU.

Genetic Linkage Map:

Parental Phenotypes)

-----gro+------ro---- -----gro------ro+----

----- gro ------ro---- ---- gro------ ro ----

Recombinant phenotypes)

-----gro+------ro+---- -----gro------ro----

----- gro ------ ro---- -----gro------ro----

If the genes were unlinked and the F1 females were mated with the F1 males, the offspring in the F2 generation would have been

4/16 = 1/4 gro+gro ro+ro

4/16 = 1/4 gro+gro roro

4/16 = 1/4 grogro ro+ro

4/16 = 1/4 grogro roro

Their phenotypic frequencies would be 1:1:1:1 related.

7 0

3 years ago