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Evolution of Australian Biota Essay

Identify features of flowers of native species of angiosperms that may be adaptations for wind, insect, bird and mammal pollination.

– Wind: Wind-pollinated plants don’t depend on the ability to attract birds or insects, so their flowers tend to be small, drab, unscented and non-prominent. Wind pollinated flowers are specially adapted to be able to make use of even slight air currents. They tend to have lots of small flowers with long filaments and pistils. Anthers and stigmata often project from the flower in order to be exposed to the wind so that pollen can be sent out and received easily.

– Insect: Flowers use nectar as a food source for insects to encourage them to keep returning to the plant. They have developed structures that secrete nectar and these structures are surrounded by petals that have pollen on them. As the insect eats or collects the nectar, it picks up pollen on its body which will then be transported to other flowers. Many plants have also developed brightly colored or dull flowers to attract insects. Scent also plays a role in attracting insects, Bees and moths like flowers with a sweet scent. Some plants even have a rotten smell to attract insects such as flies and beetles.

– Bird: Bird pollinated flowers tend to be very bright to attract the bird towards them. They produce very sticky pollen so that it clings to bird easier, they also produce lots of nectar to feed the birds. This is an example of a mutualism relationship because they both benefit from it.

– Mammal: The nectar feeding bats is one of the only mammal species that mainly feed on flowers. These flowers don’t usually have bright colours because bats don’t have good eyesight, but these flowers have a very rich scent in order for the bat to come to them. Because most mammals are larger than birds they require larger amounts of nectar which result in larger flowers. The pollen is also very sticky so that it can attach to the mammal easier so that the mammal can transport the pollen to other flowers.

Evolution: Charles Darwin’s theory was that species change over time, or evolve, in response to their environment. A good example of this is the evolution of the Kangaroo. Approximately 55 MYA the kangaroos looked quite similar to a possum and it was a tree dweller with a prehensile tail, but as Gondwana split up, the rainforests disappeared, the climate became hotter and the land dry and arid, the kangaroo evolved along the way and have come to look like what they do now. Survival: Some species have higher survival rates than others because they are more adaptable to new conditions and aren’t a completely specialized species like the Koala.

For example the platypus has survived over millions of years because it has learnt to adapt to its changing environment rather than dying off because it can’t cope with environmental change. Extinction: Most species become extinct because they can’t cope with the environmental change, and also because of introduced species that turned into competitors for territory and food. E.g. the Thylacine or better known as the Tasmanian Tiger started to die off due to competition of introduced species, mainly the Dingo. As the Dingoes numbers increased the Thylacine’s decreased because the Dingoes were hunting the Thylacines source of food and was taking over their territories.

Discuss one reason for maintaining biodiversity.

Biodiversity should be maintained because we need a variety of species within an ecosystem, and a variety within the one species because everything depends on each other for survival. As humans we depend on plants and animals as our source of food and if disease struck a particular breed of cow and that was the only breed of cow in the world, we would no longer have beef meat or dairy products, and that is where biodiversity would have helped. If there were other different breeds of cows that were available that the disease didn’t effect they would still have their meat and dairy products. So it is important to maintain biodiversity because if we didn’t our food and sources of survival would be vary scarce.

Describe two ways in which the government is involved in monitoring biodiversity.

One way is that the Smithsonian National Zoology Park has been pairing up with schools Students, teachers and community partners to experience their local environment first-hand, and become involved in projects that allow them to conduct surveys in their local ecosystem on the biodiversity of biota that surrounds them. A second way is the catch, tag and release method that most fishing departments have been adopting, like the NSW fisheries department where that have been tagging grey nurse sharks and asking for sightings of the sharks to be reported so that they can accumulate information on the population size and movement patterns of the sharks.


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