Question

Why does the seal and killer whales relationship represent a sigmoid?

Answer 1

@viendra @BiomedStudent @blues @cmkc109
plz tell me the ans y so a i read that whale is exception being herbivores still kept in secondary consumer and if we see eal and whale are not furhter eaten by any animal so we can call both of them top consumer but this graph is showing something else....i m mean sigmoid graph

Answer 2

hmm dont know, my area is more biology in the human domain really, interesting though

Answer 3

nice.... :)

Answer 4

The seal is eaten up by a shark. In most of the cases in the sea food chain, seal is considered as tertiary consumer, and shark as the quaternary consumer. The top consumer is that one which does not have any or a minimum number of predators.
Now move to the second point. A food chain has three parts exponential, transitional, and plateau.
Population growth is fastest during the exponential growth phase.
Population growth slows down during the transitional phase because disease, predation and competition set limits to population increase. Disease spreads faster as populations get larger and therefore reduces the number of individuals who can reproduce. Predators can hunt more successfully as the prey population increases, which in turn increases the population of predators (negative feedback). Resources become scarce when a population is large, which in turn increases competition.
Population growth is zero at the plateau phase because it has reached its carrying capacity, which is the maximum population size that an environment can support. At carrying capacity, populations tend to produce more offspring than can be supported by the environment. This leads to extreme competition for resources such as food, shelter, nesting space and so on.
By these points it is now clear that why the curve become sigmoid. And I think so that it should not depend upon species which are behaving as top consumers.

Answer 5

ok but @viendra u have described the factors and here they said relation btw seal and whale so it directly ayingthey are pointing to which trophic level they are included..

secondly my doubt i ehale will be secondary or top consumer??
a whale is herbivore but when it open it mouth along phytoplankton zooplankton also enter in it mouth sso cant be kept in primary o it ll be kept in econdary exceptionally but i m thinking whale can also be kept in top as it is not further eated by any one but whale never eat any animal so cant be kept in top its a contradict :P now tell me wat to do :?

Answer 6

ok but @viendra u have described the factors and here they said relation btw seal and whale so it directly saying they are pointing to which trophic level they are included..
secondly my doubt is whale will be secondary or top consumer?? as whale is herbivore but when it open its mouth along phytoplankton zooplankton also enter in its mouth so cant be kept in primary so it ll be kept in secondary exceptionally but i m thinking whale can also be kept in top as it is not further eated by any one but whale never eat any animal so cant be kept in top its a contradict :P now tell me wat to do :?