Interactions of Organisms in Ecosystems (Unit 3 – LT). KEY CONCEPT Every organism has a habitat and a niche. . A habitat differs from a niche. . Habitat. The area or environment where an organism or ecological community normally lives or occurs: . M arine habitat.
A habitat differs from a niche.
The functional role of a species in its environment‚ includes:
Food- how it fits in a food web
Behavior-interaction with other organisms and environment
Abiotic conditions it can tolerate.
I think of my niche as my job!
Clown fish living among the tentacles of a sea anemone.
KEY CONCEPT Organisms interact as individuals and as populations.
Competition and predation are two important ways inwhich organisms interact.
occurs when one organism captures and eat another.
Symbiosis is a close ecological relationship
between the individuals of two (or more) different
There are three major types of symbiotic relationships.
Bat eats nectar.
Cactus is pollinated.
Human Our eyelashes are home to tiny mites
that feast on oil secretions and dead skin. Without harming us, up to 20 mites may be living in one eyelash follicle.
Demodicids Eyelash mites find all they need to survive in the tiny follicles
of eyelashes. Magnified here 225 times, these creatures measure 0.4 mm in length and can be seen only with a microscope.
Organism is not affected
Braconid larvae feed on their host and release themselves shortly before reaching
the pupae stage of development.
The host hornworm will eventually die as its organs are consumed
by wasp larvae.
Organism is affected negatively
Ectoparasites-outside the body of host
Endoparasites- inside the body of host
KEY CONCEPT Each population has a density, a dispersion, and a reproductive strategy.
dispersionGeographic dispersion of a population shows how individuals in a population are spaced.
A survivorship curve is a diagram showing the number of surviving members over time from a measured set of births.
Survivorship curves can be type I, II or III.
Feed us now!
. Four factors affect the size of a population.
Australian farmer introduced 24 rabbits (European) in 1859 today there are ~ 300 million rabbits.
Starts slowly then becomes exponential growth but levels off as resources become scarce.