definition: This is a species whose presence is critical to the composition and integrity of the community. Example: Predators often control the population of their prey. If wolves are removed from a specific community, the population of moose increases and another predator may take the place of the wolf.

Parthenogenesis is a type of reproduction that does not require a mate. it’s rarely seen in birds and higher vertebrates. parthenogenesis involves the formation of a zygote. but this zygote is formed without fertilization. in parthenogenesis, in the absence of a male gamete, the ovum develops directly in the zygote.