Biology Notes 
Keystone Species
Niche & Habitats 




What is the difference between a habitat and a niche? Habitat is the general place where an organism lives. A niche is how an organism lives in a range of physical and biological conditions in the way a species acquires what it needs to reproduce and survive.


How is niche like a profession? I niche is like a profession because everybody has a different job. If everybody in the world wanted to be one single profession, like being a Baker, then nothing else in the world would ever get done. Professions are finding your specialty, your place, or your niche in the world. The world needs Baker's, a Baker manager, a marketing expert to sell your baked goods, advertising sales reps to go out and put together TV ads, consumers to eat your baked goods, a banker to help you with your funds that you make from baking and so on and so on. If everybody did nothing but the baking nothing else would get done.


In ecological terms describe your niche? In ecological terms my niche is to be a carnivorous student at Bainbridge island high school. I am in the middle of the food chain. I eat fruits, vegetables, wheat and I am carnivorous. Above me in the food chain are predators and most adults who seem to run things.

What is competition? Competition in biology is when two organisms are both after a finite resource and the environment. Organisms compete for food, mates and a place to live.

Why can't two organisms compete if they live in two different habitats? If two species lived in different habitats they cannot compete because they have to be going after the same finite resource in the same area for to be considered competition. If they're are two or more species competing for the same finite resource you have a competition, if the resource is easy to find and no one else's after it there cannot be a competition.


Describe how three species of warblers have divided their resources. Does each warbler have its own niche? The three species of warblers have divided up the resources so they are not in competition with one another they have found their own niche inside the trees. One warbler only eats bugs at the tops of the trees, one eats bugs in the middle of the trees one eats bugs on the bottom branches of the trees. They have each found their own niche, their own area, where there is no competition from other warblers.

What is a keystone species? A keystone species is one species that is unusually important in a habitat. It is a species that has a great effect on the other species around them if their numbers either decrease or increase dramatically the ecology of the area changes dramatically.

How can a dramatic decrease in vegetation lead to a decrease in prey species? A dramatic decrease in vegetation can lead to an increase in prey species because without vegetation there is nothing for the bugs to eat. The bugs have nothing to eat and the birds have nothing to eat because they eat bugs. Rats and mice also eat the vegetation and without vegetation they would die off as well. Predators like werewolves eat birds and mice and rats and because their numbers have greatly decreased the number of wolves would also decrease. Because everything in the wild eats everything else through the circle of life if the bottom of the food cycle, or vegetation, dies off it will affect every creature that feeds on the one before it.

What is the symbiosis? What are three main types of symbiosis? Symbiosis is a relationship where two organisms live closely together the three types of sin by doses include parasitism, mutualism and commonscalism.

Bacteria in a cows stomach helps the cow break down cellulose in grass, gaining nutrients in the process is this an example of communalism or  mutualism? The bacteria and cows stomach is perfectly normal and helps the cow break down cellulose and grass is a good example of mutualism because the bacteria needs the cows stomach contents an account needs the grass to be broken down.

What is the difference between predator and parasite? A parasite lives on or in an animal and harms it in some way either physically or by slowly taking away its food source for example. A predator it's an organism that hunts and kills other organisms for food. A predator in a parasite are different because a parasite benefits while a host is harmed and a predator and the life of prey helping itself and destroying the other.


The suffix ism means the act, practice or result of. Look up mutual and tell me the definition of mutualism


Mutualism means the act or practice of two organisms of different species exists in a relationship in which each individual benefits.



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