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Salt is notoriously dangerous to land snails; however, some populations of aquatic, freshwater snail have brackish (or a mix of salt and fresh water) water adaptations and live in different parts of a river system. A group of scientists monitored salt concentrations in the habitats of two freshwater snail populations located nearby and recorded the salt level as follows (in ppt, parts per thousand):


Population 1 (Day 1): 0.1 ppt (morning), 0.0 ppt (afternoon), 0.1 ppt (evening)


Population 2 (Day 1): 0.3 ppt (morning), 0.5 ppt (afternoon), 0.2 ppt (evening)


In 3-5 sentences, 1) describe in which population you'd expect to see more adaptations for salt water and 2) explain how such adaptations would become
more common in this population.

Respuesta :

Answer:

These aquatic snails obviously need to live in water, such as a river. Their aquatic name explains why! This means the snails will always need to live in a high salt level water area. These environmental factors have been influenced due to the different salt levels. Land snails environmental requirements are very different then the aquatic snails. For starters, their environment will obviously revolve around the land instead of the water. Also, as mentioned in the question above, salt is notoriously dangerous to land snails. Thus, they wont be around salty areas due to their safety.      

Explanation:

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Natural selection, as an evolutive force, selects beneficial alleles and increases their frequency in the population. 1) Population 2. 2) Adaptations for salt water will be favored by natural selection, and will become more common.

Available data

Population 1 Habitat         Population 2 Habitat

0.1 ppt                                          0.3 ppt                         Morning

0.0 ppt                                         0.5 ppt                         Afternoon

0.1 ppt                                          0.2 ppt                         Evening

According to this information, we can see that salt concentrations are higher in the habitat of population 2 compared to the habitat of population 1.

1) describe in which population you'd expect to see more adaptations for salt water

  • I would expect to see more adaptations for salt water in population 2, since these individuals are exposed to higher concentrations of salt than individuals in the population 1.

  • Individuals in population 2 need to survive and increase their fitness, so they must be better adapted to this environment.

2) explain how such adaptations would become  more common in this population

  • Adaptations for salt water will be favored by natural selection, and will become more common in the population.

Let us review some aspects about natural selection.

  • Natural selection, as an evolutive force, selects beneficial alleles and increases their frequency in the population.

  • It is the result of the phenotype-environment interaction which determines gene destiny in space and time.  

  • Natural selection results in adaptation, meaning that it causes an increase in the aptitude phenotype.  

  • Aptitude can be defined as the contribution of each genotype to the next generation.

  • Aptitude (or fitness) is reflected by the phenotype that results in the survival, fertility, and capability of having a mate. It is a way of measuring the individual ability to leave fertile offspring.

  • Aptitude must be significant to the natural selection act in its favor.  

  • Natural selection can act favoring an allele or against it, according to how it affects the fitness of individuals.

  • In many cases adaptations, resulting from natural selection can be correlated to environmental factors or selective pressures applied by other organisms or habitats.  

  • The selective agent is the environmental trait that determines the differential survival of the phenotypic classes. The environment influences the probability that each genotype passes its gametes to the next generation.  

  • 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 this example,

  • The selective pressure is higher concentrations of salt in water

  • This environmental pressure leads to the occurrence of a mutation in one or a few individuals

  • These mutated individuals get to survive and reproduce better than the non-mutated ones

  • Since the mutation turns out to be beneficial for population 2, it is favored by natural selection.

  • The mutation spreads in population 2, and becomes more common

You can learn more about natural selection at

https://brainly.com/question/2725702

https://brainly.com/question/1657375

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