Unit 3 VCE Environmental Science

Area of Study 2: BiodiversityBritt Gow, 2012

Definition:

• Biodiversity (biological diversity) is the total sum of all the living organisms that exist on our earth.

• This living wealth is the product of hundreds of millions of years of evolutionary history.

• “The variability among living organisms from all sources including terrestrial, marine and other aquatic ecosystems and the ecological complexes of which they are a part; this includes diversity within species, between species and of ecosystems” International Convention on Biological Diversity.

Biological Diversity• Today's biodiversity is the result of billions of years of

evolution, natural processes, and in more recent years, human activity. Before Homo sapiens, the Earth's biodiversity was much greater than it is today. Human activity has had a tremendous impact on biodiversity due to use of Earth's resources and exponential population growth.

• The total number of species on Earth today is estimated to be around 10 million different species, but could be as low as 2 or as high as 100 million. New species are discovered often, and many that have been discovered have not yet been classified. The richest sources of biodiversity on Earth are found in tropical rainforests and the ocean.

Three Levels:• Genetic Diversity – genes on chromosomes

determine the specific characteristics (physical, emotional) of individual organisms. Diversity of genes within a species and processes such as mutations, gene exchanges, and genome dynamics that occur at the DNA level and generate evolution.

• Species Diversity – variety of different types (species) of organisms

• Ecosystem Diversity – variety of different ecosystems from marine to desert to tropical rainforest to temperate Eucalypt forest to wetlands etc.

http://www.epa.gov/eerd/APMnew.htm

Genetic Diversity• The reason captive breeding programs need to introduce

new individuals from wild populations.• a species with high genetic diversity will tend to produce

a wider variety of offspring, where some of them may become the most fit variants.

• In contrast, a species that has little or no genetic diversity will produce offspring that are genetically alike and therefore will likely be susceptible to diseases or problems similar to those of their parent.

• Hence, little or lack of genetic diversity reduces biological fitness and increases the chances of species extinction.

• Larger populations have greater genetic diversity and are therefore less vulnerable to change and more adaptable and sustainable.

Geneticists are working to improve our food crops by making them less vulnerable to disease, droughtand crop failure. Humans need to provide food for a growing population by increasing productivity.

Genetic studies show that the cheetah has a very low genetic diversity, indicating that the population has crashed to about 200 individuals at some time in the past. They are vulnerable to extinction for this reason.

“The existence of a wide range of different types of organisms in a given place at a given time. The diversity of plant and animal life in a particular habitat.”

Species Diversity can be measured by counting the number of organisms of each species.

Ecosystem Diversity

• Variety of habitats, living communities and ecological processes in the living world.

• Includes alpine, dry-schlerophyll, mallee, tropical rainforest, savannah (grassland), freshwater aquatic, temperate marine, Antarctic etc, each with it’s own characteristic species and food webs.

• Often preserved by National parks and reserves.

Australian Biodiversity

• Australia has an incredibly diverse range of life due to it’s isolation from other continents.

• Australia is recognised as one of the most mega-diverse countries on the planet, with many endemic species, such as our iconic marsupials and monotremes, banksias, eucalypts and grevilleas.

Why Conserve Biodiversity?

• Ecosystem services• Biological resources• Social benefits

Products Services Social Benefits

Plants (trees, grasses, palms, herbs)

Fungi

Micro-organisms

Invertebrates

Vertebrates

Conservation of Biodiversity

• Genetic – variety of breeding pairs in captive programs, different groups in separate locations

• Population – conserving a particular population within a precise geographic area

• Species – preserving different species of organisms (management plans)

• Ecosystem – National parks and conservation reserves

Assessment of Biodiversity

• Species richness (no. of different species)• Species diversity (abundance of each different

species)• Simpson’s Index • Shannon-Weiner Diversity Index

Threats to Biodiversity - CHIPPO

• Climate Change• Habitat destruction• Introduced animals• Pollution• Pest plants• Over-harvesting

IUCN Conservation Categories

• Extinct• Extinct in the wild• Critically endangered• Endangered• Vulnerable• Conservation dependent• Data deficient• Low risk• Not evaluated

Strategies for protecting Biodiversity

• Action plans• Captive breeding programs• Conservation reserves• Revegetation and habitat restoration• Feral species control• Ecotourism• Education

Project Eden: Shark Bay, WA

Keeping Feral Species Out