Which is NOT a step in the emergence of life proposed in the Oparin hypothesis?

Vascular plants have <span>specialized tissues that can transport fluids - vascular tissue. This tissue consists of</span><span> xylem and phloem. Xylem transports water and minerals from the root to the upper parts of the plant. Phloem transports food and nutrients from the leaves, where they are produced, to the growing or storage parts of the plants. </span>

6 0

3 years ago

Provide an adaptive and a nonadaptive hypothesis for the evolutionary loss of useless organs, such as eyes in many cave-dwelling

Zepler [3.9K]

In order to be able to Provide an adaptive and a non-adaptive hypothesis, the following is required

<h3>What is adaptation?</h3>

It refers to a trait or an integrated set of traits that increases the fitness of an organism. It is the process of improving the fit of phenotype to environment through natural selection.

<h3>What is non adaptation?</h3>

it refers to those traits that do not result in the better adaptation of the organism to its environment, and does not increase the genetic fitness of the organism.

Let us take the case of vain organs. There may be a metabolic value to constructing a vain organ, and subsequently the humans who have misplaced that organ might also have a selective advantage. Also, if the organ is useless, the mutations that disrupt the improvement of that organ would be evolutionarily neutral, and may want to unfold to fixation via genetic drift.

So an adaptive hypothesis as to why an organism may lose useless organs is energy trade offs. The organism may additionally be losing energy in growing and retaining a vain organ, whilst this strength can be higher used someplace else. So an organism that lives in a darkish cave might also sooner or later lose its eyes considering eyes are of no use inside a darkish cave.

A non adaptive hypothesis for the evolutionary loss of organs can be random mutation. If a random mutation occurs that causes an organism to lose its eyes, in a dark cave where it does not use its eyes anyway, it could still survive, reproduce and pass that mutation down.

For more information on adaptive hypothesis, visit

brainly.com/question/975242

3 0

2 years ago

A gene that affects hair length in dogs has two alleles. The allele for short hair (L) is dominant

Lelechka [254]

Answer:

This question lacks options, the options are:

A. Only recessive alleles are inherited from homozygous parents.

B. Dominant alleles grow weaker as they are passed from parents to offspring.

C. Only the parent with a dominant allele can pass that allele to offspring in sexual reproduction.

D. A heterozygous parent has an equal chance of passing either the dominant allele or the recessive allele to offspring.

The answer is D

Explanation:

This question involves a single gene coding for hair length in dogs. The allele for short hair (S) is dominant over the allele for long hair (s). This means that allele 'S' will always mask the phenotypic expression of allele 's' in a heterozygous state.

According to the question, two heterozygous dogs (Ss) were crossed to produce 6 shortt-haired offsprings and 2 long-haired offsprings. An heterozygous organism is that which contains two different alleles for a particular gene i.e. a combination of dominant and recessive alleles.

Based on this, during meiosis or gamete formation, an heterozygous dog (Ss) will produce gametes with the short hair allele (S) and long hair allele (s) in equal proportion i.e. 50-50. When the two gametes containing the recessive alleles (s) produced by each heterozygous parent fuses, an offspring with a recessive phenotype (long hair, ss) is produced.

Hence, a long-hair

phenotype can appear in the offspring of two short-haired dogs because a heterozygous parent has equal chance of passing either the dominant or recessive allele to the offspring.

6 0

3 years ago