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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