What is the cause for most of the species lost?
Human land use practices that destroy natural habitats, worst in the tropical rainforest.
How much of all land surfaces have been transformed by human activity?
1/3 to 1/2
What is the average lifetime of most species?
Between 1-10 million years.
How many species exist today?
1.4 million
What are keystone species?
A species that plays a vital role in the
operation of an ecosystem.
When did the modern mass extinction begin?
When the
first humans evolved and spread to colonize larger
and larger areas (Figure 20-1). Estimates suggest that
approximately 70% of the large mammal genera of
the Late Pleistocene Epoch are extinct.
Where does the most pecies lost take place?
In the tropical rainforest which are also the most diverse of the terrestrial ecosystem.
How of a porportion of all living things live in the rainforest?
3/4 of all living things
2/3 plants
What does deforestation in the tropics lead to?
Deforestation in the tropics is wiping out
species faster than they can be catalogued
and much faster than they can be studied.
Every day, species are going extinct that we
do not even know exist.
Name 3 instrumental value of a species that can be viewed:
- Pharmaceuticals
- Recreation value
- Scientific value
- Commercial value
