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12345 [234]
3 years ago
12

What is the answer to this question?"explain two difficulties an ecologist might have in counting a population of migratory bird

s. Develop and explain a method for estimating the size of such a population"
Biology
1 answer:
dimulka [17.4K]3 years ago
6 0
<span>It may be difficult for ecologists to determine the size of a bird population if that population migrates to different locations throughout the year. During migration, some birds may split off from the group and not return, others may die, and still others may join. Therefore, the bird population will be in constant flux. It is hard to know, when the birds return to their prior location, if the population consists of the same group of birds (in addition to deaths and births) or whether it has grown or shrank through other means. However, to estimate the size, an ecologist can track a migratory flock through several years, counting each year to get a general sense of the population size. Additionally, given one measurement, an ecologist could consider the average lifespan and birth rates of the population to extrapolate the size of the population in subsequent years.</span>
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In jimsonweed, purple flower (P) is dominant to white (p), and spiny pods (S) are dominant to smooth (s).
iragen [17]

Answer:

See attached image for detailed punnet squares and diagrams

a) F1 generation: Purple flower and spiny pods (PpSs) offsprings

b) F2 generation: Puple flower, spiny pods (9), Purple flower, smooth pods (3), White flower, spiny pods (3), white flower, smooth pods (1).

c) The progenies are: PpSS (4), PpSs (4), ppSS (4), and ppSs (4)

d) The progenies are: PPSs (4), PPss (4), PpSs (4), Ppss (4)

Explanation:

This question involves two distinct genes in jimsonweed; one coding for flower colour and the other for pod texture. The alleles for purple colour (P) and spiny pods (S) are dominant over the alleles of white flower (p) and smooth pods (s) in the two genes respectively.

A true-breeding plant with white flowers and spiny pods will have genotype: ppSS while a true-breeding plant with purple flowers and smooth pods will have genotype: PPss. In a cross between these two parents, the following combinations of gametes will be produced:

ppSS- pS, pS, pS and pS

PPss- Ps, Ps, Ps, PS

a) Hence, the F1 offsprings from this cross will possess a heterozygous genotype: PpSs, which is phenotypically purple-flowered and spiny-pod.

b) if the F1 offsprings are self-crossed i.e. PpSs × PpSs, gametes PS, Ps, pS, ps will be produced by each parent. These gametes will be used in a punnet square (see attached image) to produce the following F2 offsprings in proportion:

Purple flower, spinny pods (9)

Purple flower, smooth pods (3)

White flower, spiny pods (3)

White flower, smooth pods (1)

c) if the F1 offsprings are crossed back with the white, spiny parent i.e. PpSs × ppSS. The following progeny of offsprings will be produced: (see attached image)

PpSS (4),

PpSs (4),

ppSS (4), and

ppSs (4)

d) if the F1 offsprings are crossed back with the purple, smooth parent i.e. PpSs × PPss, the following progeny will be produced:

PPSs (4),

PPss (4),

PpSs (4), and

Ppss (4)

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the evidence presented would most support which type of isolating mechanism morphological

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