Answer:
Gonadotropins are polypeptide hormones and are secreted by the anterior pituitary gland.
Explanation:
Hypothalamus releases GnRH i.e gonadotropin releasing hormone which stimulates the anterior pituitary to secrete gonadotrophs such as FSH, ICSH and LH.
FSH (follicle stimulating hormone): In males it stimulates spermatogenesis. In females it stimulates growth of ovarian follicles.
ICSH (Interstitial cell stimulating hormone): In males, secretion of testosterone.
LH (Luteinising hormone): In femalestogether with FSH, it triggers ovulation, stimulates conversion of broken ovarian follicle into corpus luteum.
The red-legged frog breeds in ephemeral ponds from January through March. Its relative, the bullfrog, breeds in permanent ponds from late March through May. There are two pre-mating isolation mechanism at play here,
1. Ecological isolation: The habitats are different, hence the individuals of both the species do not meet. Ephemeral ponds are temporary ponds that develop during rainy days, while the permanent ponds are full of water throughout the year.
2. Temporal isolation: The time of mating is different for both the species to avoid contact between the individuals of closely related species. Red-legged frogs mate in January to March slot and the bullfrog in the March to May slot.
