Transcript habitat

An introduction to Ecology –
Habitats, environment and survival
Unit 2, Area of Study 1 – organisms
and their environments
What is Ecology?
• Ecology is the study of the relationships
between organisms and their environments.
• The habitat (where the organism lives)
• The other organisms it lives with
• The non-living parts of the habitat
Habitat
• All organisms live in a particular area, called a
habitat.
• Organisms are suited to their particular
habitat.
• Organisms live in all types of habitats, even
those that are considered “extreme” – very
hot, acidic, cold, salty etc. Many of these
“extremophiles” are bacteria
Light-emitting bacteria
DEEP SEA
ANGLERFISH
Types of habitat
• General descriptions:
• Terrestrial (on land)
• Aquatic (in water – may be freshwater or marine, or
estuarine [living in the river mouths that open to the
ocean])
Microhabitats
• Within a larger habitat (for example, a forest
habitat [called a biome in the following
diagram]), there are a number of different
areas that different organisms call home.
These are microhabitats.
Resources
• Animals live in particular habitats for their
resources. This usually includes water, shelter,
food, nesting/breeding sites.
• Habitats are not uniform in the amount of
resources. For example, a frog living in a pond
may use the water for shelter and hydration,
but breed on the edges of the pond, and need
sunlight and air from the outside of the pond.
Range
• The area that encloses all the habitats the
organism lives in is the range or distribution
map of the species.
• Within the range, there may be areas of
plentiful organisms, or areas where they are
rare – a large range does not necessarily mean
that a species is common
Range of Australian wombat
species
Range changes
• Over time, the range of a species can change,
usually due to change in habitat (eg. The
clearing of forests)
• Many Australian native species have a
shrinking range
The changing distribution of the
introduced Cane Toad
Absence from a region
• There are a number of reasons an organism
might NOT live in a particular habitat:
– Unsuitable environment
– Geographic barriers
– Competition – another organism competing for
the same resources
Migration
• Some mobile organisms travel long distances
between widely separated habitats
• Annually
– Humpback whales spend summer feeding and mating in
Antarctic water, but travel to Australia when it gets too cold,
where the females give birth
– Bogong moths are caterpillars in QLD and NSW in winter.
When they become moths, they hibernate in the Snowy
Mountains, then fly to the north again in autumn to mate
• Once in their life cycle
– Short-finned eels mature in freshwater lakes in southern and
eastern Australia, but when they are sexually mature, they
swim across to their breeding areas in deep ocean near New
Caledonia. Larvae hatch and are carried back to Australia,
where they swim up freshwater rivers to lakes to mature.
Glossary words...
Ecology, habitat (or biome), microhabitat,
terrestrial, aquatic, resources, range,
migration, competition.
Page 263 – Quick Check questions
Homework: Read about Technology as a Tool in
Biology (pp 263 – 266) and answer Quick
Check questions pg 266
Niche
• In a habitat, many species live together.
• They all must somehow share the resources
which are there, or must require different
resources
Niche definitions
• “the way of life of a species”
• “the role or profession of a species in a
community”
• “the way of life of an organism”
• “the status or role of an organism in its
community”
Niche continued
• Each species has its own niche, which may be
described in terms of the resources it uses:
– Where it lives
– What it eats
– When it feeds
– The environmental conditions it tolerates (eg.
Temperature, amount of sunlight)
Describing niche
• Niche is usually described in words, for
example, “its niche is that of a leaf-eating
herbivore that feeds by day in the canopy of a
tropical rainforest”.
• Have a go at writing niche description for the
following organisms:
• Desert cactus
• Giraffe
Niche overlap
• When more than one species in a habitat
occupies the same niche, or part of the same
niche (eg. It requires the same food or shelter
source), there is niche overlap
• Niche overlap means that there will be
competition between species for the same
resources, with one species undoubtedly
being the stronger species
Niche overlap continued
• The result of niche overlap is that one of the
species will be either excluded from that
habitat, or will have to adapt to fill a different
niche.
• This, sadly, often happens when a species is
introduced, and it pushes out a native species
– Eg. Rabbits have out-competed small herbivorous mammals in
many areas of Australia
• Natural habitats have zero or very little niche
overlap
Glossary etc
Niche, niche overlap
Pg 270, Quick Check questions