- ECOSYSTEMS and BIOSPHERE:
An Ecosystem consists of all the living species in a particular place, plus all the nonliving matter (rock formations, soil, water, air) with which they interact.
The Biosphere is the ecosystem of the entire planet, including both tertrestrial and marine habitats.
All species in the biosphere interact with other species and with their physical surroundings. Ultimately, every living species interacts, however indirectly, with all the others.
- BIODIVERSITY:
Biodiversity is measured by the number of species of organisms (estimated around 10 million) inhabiting our planet,
by the diversity of their interactions with
other species, and by the genetic diversity that exists within each species.
About half of the known species on planet Earth are insects, of which two-thirds are beetles (Coleoptera).
About one-quarter of known species are flowering plants (Angiosperms).
The most diverse ecosystems on Earth are Tropical rain forests. About 50% of all terrestrial species live in tropical rain forests.
The most diverse aquatic ecosystems are Coral reefs.
Speciation (the splitting or multiplication of species) increases biodiversity. Extinction of any species decreases biodiversity.
Because of the many interactions between and among species, the extinction of any one species is a threat to many others, including humans.
- THREATS TO BIODIVERSIY:
Extinction of any species is a threat to biodiversity.
Hunting and poaching are obvious threats.
HABITAT DESTRUCTION, however, is a much greater threat, as it threatens many species at once.
- Some habitats are destroyed to make room for human habitation. Mining operations also threaten many habitats.
- Agriculture, however, is the greatest threat to habitats, because many tropical forests and other habitats are cleared to make way for agricultural fields.
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