Biological diversity or biodiversity is the variation of life forms on earth. It encompasses the many plants, animals, microorganisms, their genetic makeup and the ecosystems in which they live. It is usually viewed at three levels – genetic diversity, species diversity and ecosystem diversity.
- Genetic Diversity – this is the variety of genes within a species. Different geographic populations of species will have varying genetic compositions. Therefore to conserve genetic diversity, different populations of a species need to be conserved.
- Species Diversity – this is seen at a habitat or regional level. Some habitats such as rain forests are quite diverse, being home to a variety of species, whereas others (eg. salt flats) have much less. It is important to maintain species diversity within habitats to ensure they are functioning productively.
- Ecosystem Diversity – this is the variety of ecosystems within a specific region or area. As mentioned above, an ecosystem is a community of organisms interacting with each other and their environment and can vary greatly in size.
Natural selection is not the only source of genetic change in the evolution of species. The chance failure of progeny to reproduce the exact gene proportions of their parents may also cause gene frequencies to change. This is termed "genetic drift" and it becomes very important in small populations, where genes may be lost from the original gene pool simply by not being represented in successive matings. In addition, when a few individuals migrate from a population and found a new isolated population, the gene frequency can change if these migrants do not carry a full range of genes. This is called the founder effect.
Because all the established genes in a population have been monitored for fitness by natural selection, newly arisen mutations are unlikely to enhance fitness unless the environment changes so that it favours the new gene activity.
The novel genes that cause large changes rarely promote fitness and they are usually lethal. The genes that are already established by selection are carefully adjusted to one another so that their biochemical effects are coordinated. Mutations that have small effects provide a basis for genetic changes that seem to promote fitness in laboratory experiments.
The habitat of an organism (plant or animal) is the environment where it
A good habitat is any environment where animal species can occur, survive and reproduce.
There are five main types of habitat:
- Large trees (both living and dead)
- Under storey habitats (eg. trees and shrubs of varying sizes)
- Dry ground habitats (eg. rocks, logs, ground cover plants and grasslands)
- Wet ground habitats (eg. beaches, mangroves and wetlands)
- Aquatic habitats (eg. marine, estuaries and lakes)
A life span is the length of time in an organism's life, from conception to death. Most multicellular organisms pass through the following 3 phases:
- Embryonic Phase - Starting with the first division of the fertilised egg
- Juvenile Phase - Organism grows to sexual maturity
- Adult Phase - Organism reaches the peak of sexual productivity and then begins a decline in physiological activities, ultimately ending in death.
Different species have characteristic life spans that vary greatly in duration of the various phases and in the total length of life span. For instance, mayflies are adults for only one day of their lifespan of one year, but human beings spend approximately seventy per cent of their total life span as adults.
Wild animals in different ways and vary greatly in the distances they travel. Some may use corridors to travel to find food and mates. Others, such as the koalas follow their nose, crossing pastures and residential areas to get to certain home range trees. Some animals are quite territorial whereas others may be transient or migratory.
The movement patterns of particular species need to be catered for when managing populations and planning for wildlife.
Wildlife management is the manipulation of wild animal populations and their habitats in the context of an ecosystem.
Wildlife management includes activities such as:
- Managing parks and reserves
- Altering and rehabilitating wildlife habitats
- Providing education and extension programs for special interest groups
- Maintaining threatened populations and pests at a desirable level
- Protecting human life and property
- Managing harvests of wildlife.
The techniques and types of wildlife management vary depending on your location, and as with any job, you will find that you will need to carry out research into the local methods and types of wildlife management.
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