Following statements are regarding to signals that regulate axis extension in chick embryos.

A. In the stage 10 chick embryo, Fgf8 inhibits expression of the retinoic acid (RA) synthesizing enzyme Raldh2 in the presomitic mesoderm and the expression of the RA receptor RARβ in the neural ectoderm, thus preventing RA from triggering differentiation in the caudal-lateral epiblast cells and the caudal-most paraxial mesoderm.

B. Fgf8 inhibits Sonic hedgehog (Shh) expression in the neural tube floorplate, controlling the onset of ventral patterning genes.

C. FGF signaling is also required for expression of Delta1 in the medial portion of the caudal-lateral epiblast cells and promotes expression of Wnt8c.

D. Fgf8 decays in the caudal paraxial mesoderm, Wnt signaling, most likely provided by Wnt8c, now acts to promote Raldh2 in the adjacent paraxial mesoderm. RA produced by Raldh2 activity expresses Fgf8 and Wnt8c.

Which of the following statements are correct?

#Question id: 3407

#Unit 9. Evolution & Diversity of Life Forms

Natural selection can act in three main ways on a character, such as body size, that is continuously distributed. Following graph represent fitness and their relative body size after the exposure of natural selection at different way? Which of the above population influence to which type of natural selection?

#Question id: 3408

#Unit 9. Evolution & Diversity of Life Forms

New species originated via punctuated equilibrium having some characterstic feature

a. occur during cladogenesis from ancestral species

b. subpopulation of ancestral species transform in to new species

c. Morphological change is sudden and rapid

d. continuously change in their morphology

which above statement is correct

#Question id: 3409

#Unit 9. Evolution & Diversity of Life Forms

All genetic drift arises from sampling error, but there are several different ways in which sampling error can arise as a following

a. Reduced population size

b. Founder effect

c. Genetic bottleneck

d. Mate choice

Which of the following above way cause sampling error in succeed generation?

#Question id: 3410

#Unit 9. Evolution & Diversity of Life Forms

1200 Birds population are present around costal area with allelic frequency of M1 .60 and M2 .40. During rainy time 200 birds come from nearest forest which has .30 frequency of M1 and .70 of M2 allele.  What will be allelic frequency of M2 in their recipient population of costal area?

#Question id: 3411

#Unit 9. Evolution & Diversity of Life Forms

The frequencies of two allele’s p and q for a gene locus in a population are 0.8 and 0.2, respectively. Population show inbreeding with value of F is .25, Assume that the population is infinitely large and no other evolutionary force is acting. The heterozygote frequency will be 

#Question id: 3412

#Unit 9. Evolution & Diversity of Life Forms

What will be frequency of inbreeding coefficient between G and H?