8.2 - Biodiversity

Concept of Biodiversity

There are 3 types of biodiversity – genetic diversity, species diversity and ecosystem diversity.

Genetic diversity

• Individual gene variation in a population and the gene variation between different population of the same species.
• The gene differences are due to individual isolation and adaptation in different environments.
• For example, the different gene combination formed allows the gene variation in plants such as paddy which are cultivated to produce many varieties of rice.

Species diversity

• Variation and variability of organisms on Earth.
• Includes the total number of species in a community (species richness) and the species distribution in a community (species evenness).
• For instance, millions of species can be found in the tropical rainforests (millions of species of insects and plants).

Ecosystem diversity

• Variety of biotic community habitats in dan the ecological process in the ecosystem with different habitats.
• For example, ecosystems rich with biodiversity such as the ocean, land, desert and swamp.

Phylogenetic Tree

Phylogeny refers to the evolutionary history of a species of organisms. The phylogenetic tree is a diagram that shows the evolutionary relationships among a group of organisms.

Phylogenetic classification

• A classification system that represents the evolutionary relationships and history of the organisms studied.
• Made based on the homologous structures, that is the anatomical structures which share the same ancestor although their functions differ from one organism to the other.

Figure 2 - Humans, dogs, bats and seals have the same types of bones, the only differences are their sizes and lengths. This shows that all four of the animals originate from one common ancestor.

For plants, the land plants are said to have evolved from the green algae.

Figure 3 - Plants with no vascular tissues are the first land plants, followed by vascular plants without seeds. Vascular plants will then develop into vascular plants with seeds (gymnosperm and angiosperm). Angiosperms are the most successful flowering plants because their seeds are protected in their fruits.

The Importance of Biodiversity on the Environment and Humans

• Source of food, medicine and education.
• Maintain balance of the nature.
• As a recreational area.
• Used in scientific research.

In situ conservation refers to maintaining the species in their natural habitats whereas ex situ conservation means conserving the species outside of their natural habitats.