Ecology O2 Nutrients CO2 Ecology is the study of
therelationships betweenorganisms and their physicaland biotic
environment: Relationships involveinteractions with the
physicalworld as well asinterrelationships with otherspecies and
individuals of thesame species. Biological Complexity
Living organisms can bestudied at different levels ofcomplexity.
From least to mostcomplex, these levels are(in an ecological
context): Individual Population Community Ecosystem Biome Biosphere
Biosphere Biome Ecosystem Community Population Individual The
Biosphere The biosphere isthe region within which all living things
are found on Earth. It is the narrow belt around the Earth
extending fromthe bottom of the oceans to the upper atmosphere.
Image: NASA Exploring the Biosphere
Life exists in all places, from blind white crabs in lightless
environments... Our knowledge of what constitutesthe biosphere
continues todevelop as scientists continuetheir exploration of the
Earth. The biosphere extends into theEarths crust, below the
oceansand deep into rock fissures; itextends well into the Earths
upper atmosphere. to tube worms in the crushing ocean depths.
Lichens are found on rocks, trees, and bare ground.
Habitat An organisms habitat is the physical place or environment
inwhich it lives. Organisms show a preference for a particular
habitat type, butsome are more specific in their requirements than
others. Most frogs, like this leopard frog, live in or near fresh
water, but a few can survive in arid habitats. Lichens are found on
rocks, trees, and bare ground. Habitat Range An organisms habitat
is not always of a single type. Some organismsoccupy a range of
habitats. There are various reasons why: Highly adaptable in
habitat requirements. Different, but equivalent, resources
available in different habitats. Reduced competition for resources
in sub-optimal habitats. Habitat extremes may influence growth
form, especially in plants. Habitat Preference Organisms may select
particularareas within their general habitat,even in apparently
homogeneousenvironments, such as water.This is termed habitat
preference. Example: Aquatic organisms mayshow a preference for a
particularsubstrate type, water depth orvelocity, water clarity, or
degree ofvegetation cover or habitatdisturbance. Knowledge of
habitat preferencecan be used to protect species intheir
environment. Damselfly nymph Rainbow trout Resources in a Habitat
The habitat provides organismswith the following resources: Food
and water sources Mating sites Nesting sites Predator avoidance
Shelter from climatic extremes However, the organism may ormay not
have the adaptationsto exploit all the availableresources fully.
Adaptations An adaptation (or adaptivefeature) is an
inheritedfeature of an organism thatenables it to survive
andreproduce in its habitat. Adaptations are the endresult of the
evolutionarychanges that a species hasgone through over time.
Adaptations may be: behavioral physiological structural
(morphological) Osprey: a diurnal bird of prey Spotted owl: a
nocturnal bird of prey Exploiting a Habitat Organisms have
adaptations toexploit, to varying extents, theresources in their
habitat. Where resource competition isintense, adaptations
enableeffective niche specializationand partitioning of resources.
In the African savanna, grazingand browsing animals
exploitdifferent food resources withinthe same area or even
withinthe same type of vegetation.