Biology Answers

Two sister species of butterflies, Heliconius melpomene and Heliconius cydno, each mimic a different model species. While these species are largely sympatric, there are some areas in which H. melpomene occurs alone (i.e., allopatric to H. cydno). Mating studies show that H. melpomene females from these allopatric populations are more responsive to courtship by H. cydno males than are H. melpomene females from sympatry. What mechanism could explain this stronger behavioural isolation in sympatric compared to allopatric H. melpomene populations?

a) trait-based reproductive barriers

b) reinforcement

c) ecological speciation

d) prezygotic isolation

e) behavioural isolation

Two sister species of insects feed on different parts of the

same plant species, one on the stem and the other on the leaves. Hybrids between the insect species grow more slowly and have reduced survival, indicating some form of postzygotic barrier. Outline conceptually what you would need to show to infer that ecological speciation is the mechanism generating this reproductive barrier, and briefly

describe how you might test this.

Which promoter initiates which life cycle (lysogenic & Lytic)? Mention both types of promoters and their characteristics.

Which consumes energy anabolic or catabolic

Tendency of the solute to spread throughout the solution until the composition is homogeneous

As a youth leader of an environmental group who promotes and spreads awareness about protecting our biodiversity, in order to let your fellow citizens be aware with it.

CI has more binding capacity to the DNA than CRO- Justify the statement.

discuss the mechanism of metabolic pathway control using hormonediscuss the mechanism of metabolic pathway control using hormone

The shape and the colour of radishes are controlled by two independent pairs of alleles that show no dominance; each genotype is distinguishable phenotypically. The colour may be yellow (YY), purple (Y′ Y), or white (Y′ Y′) and the shape may be long (LL), oval (L′ L), or round (L′ L′). using the Punnett square method, diagram a cross between yellow, long (YYLL) and white, round (Y′ Y′ L′ L′) radishes and summarize the F2 results under the headings phenotypes, genotypes, genotypic frequency, and phenotype ratio.

If tryptophan is absent from the environment of E.coli, the trp operon will be _______