Post on 04-Jan-2016
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1.2 Interdependence All species rely on many others for
survival
Symbiosis – The relationship between individuals of two different species over time.
Types of Symbiosis Commensalism – one organism
benefits while the other is unaffected.– Barnacles attach to a whale to move to
other areas…the whale is unaffected.
Mutualism – both species benefit– Cow birds sit on backs of cows and eat
the bugs off them…the birds get food while the cows get cleaned.
Parasitism – one organism benefits while the other is harmed.– Tapeworm attaches to the intestines of a
human. The tapeworm gets nutrients from food in intestine, leaving little food for the human.
Symbiotic relationships are examples of extreme interdependence.
Predator/Prey relationships are also a form of interdependence!!– E.g. Lynx and Hare
Niches – role of an organism in an ecosystem
Interspecies competition – when two or more species need (compete for) the same resource.
This is one type of interaction between species where neither species benefits.– E.g. two species competing for the same
food source will both have less food=starvation in the population.
COMPETITION
Interspecies competition puts limits in the size a certain population will be.
So How do so many species exist together in the same place?
They all have specific NICHES!!!– What it eats, what eats it, its habitat,
nesting site, range(how far does it roam), its effect on populations around it and its environment…
Niches vary from population to population.– The niche a population occupies may
change over time. E.g. frog tadpole – aquatic environment
– Adult Frog – aquatic AND terrestrial environment
Resource Partitioning
Division of a resource among two or more coexisting species so that the niche of each species differs slightly.
Homework
Page 19 Questions 1,2,3,4