Apart from being a part of the food chain, predators play other important roles. Mention any two such roles supported by examples.
Predators play an important role in:
1.Maintaining the prey population; this regulates intra-species competition. This also helps in checking any overgrazing by herbivores, which might ultimately lead to an unbalanced ecosystem. For example, if tigers are removed from a forest, spotted deer will multiply rapidly. This would result in rapid destruction of herbs and grasses in the forest and ultimately the whole forest.
2. Indicating ecological disturbances. Usually predators are small in number and highly sensitive to ecological changes, owing to their excessive adaptation. For example, Gharials are extremely adapted to their freshwater habitat. They start dying rapidly and in large numbers as soon as a river starts getting polluted, thus indicating ecological disturbances.
Fill in the blanks:
(a) Humans reproduce __________. (asexually/sexually)
(b) Humans are__________. (oviparous/viviparous/ovoviviparous)
(c) Fertilization is __________ in humans. (external/internal)
(d) Male and female gametes are __________. (diploid/haploid)
(e) Zygote is __________. (diploid/haploid)
(f) The process of release of the ovum from a mature follicle is called__________.
(g) Ovulation is induced by a hormone called the __________.
(h) The fusion of male and female gametes is called _____________.
(i) Fertilisation takes place in _____________.
(j) Zygote divides to form _____________which is implanted in uterus.
(k) The structure which provides vascular connection between fetus and uterus is called ____________.