Habitats and environments: Micro
An organism's habitat is "where it lives", such as under
the bark of a tree, in an aquarium, or a desert. Its environment is
the set of all the factors, both living and non-living, which affect
its survival. (See Factors
affecting survival: Abiotic and Factors
affecting survival: Biotic)
Around the school playground are many distinct micro-habitats with
specific environmental conditions. Each will be "home" to
particular organisms because they have adaptations which allow them
to survive well in those conditions.
Tree
A tree could be home to birds in the upper branches,
bees and ants which eat the nectar of the flowers, possums which eat
the fruit, caterpillars feeding on the leaves, as well as spiders and
beetles under the bark. The conditions in the branches, though, are
quite different from under the bark.
Rotting log
A rotting log is a warm, moist, and safe habitat protected from many
predators. It soaks up water making it ideal for mosses, lichens and
small ferns and small animals which may dehydrate. Fungi and bacteria
feed on the dead wood tissue. Spiders fix egg cocoons under the bark,
and many mites, beetles, slugs and snails live in the rotting leaf litter
under the log. Wood-boring grubs use their sharp cutting jaws to chew
through the wood, and cellulose-digesting bacteria in their gut break
down the wood fibres. Millipedes feed on rotting leaves and dead worms
and insects. Centipedes kill worms and spiders for food. Larger logs
may also provide protection for small amphibians such as frogs and reptiles
like skinks.
Compost heap
A compost heap begins life as a heap of waste vegetation including garden
and kitchen scraps. The heap begins to warm up as bacteria break down
the plant foods and release energy, some of which is in the form of
heat. Fungi then start to grow on the woodier materials giving off chemicals
which aid digestion of the decaying vegetation. Numerous "minibeasts"
such as mites, slugs, slaters and millipedes move in. Blowflies lay
their eggs in the warm moist heap and the larvae develop quickly providing
food for compost predators such as beetles and earwigs. Earthworms eat
their own weight in decaying vegetation each day. The middle of the
heap offers warmth, moisture and protection for young. Within a week
the heap may be steaming, but mature compost takes up to six months
to form. Animals in the heap need air and water, so the heap will not
rot down if it is too dry, too waterlogged or not turned over to allow
air circulation.
Buildings
In buildings, animals take advantage of warmth, shelter and food.
To many animals, wooden furniture is like a fallen log, attics are like
caves and walls are like cliffs. Clothes moths and carpet beetles live
on household fabrics, flies contaminate our food, birds nest under eaves
and roof linings, possums and bats can build nests in the roof, mice
make nests of chewed paper and straw, and spiders frequent dark corners.
Cockroaches and earwigs like warm kitchens with weevils sometimes inhabiting
the rice or flour canisters. Our pets may harbour fleas, and the carpets
and bedding house billions of microscopic dust mites.
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