several mass extinctions have occurred in earths history are we currently living during another mass...
TRANSCRIPT
Several mass extinctions have occurred in Earth’s history
Are we currently living during another mass
extinction?
Biodiversity- refers to the number and variety of species on Earth Known species= 1.7 million Estimates = over 10 million
Species are considered known when they are collected and scientifically described
Species diversity- # of different species in an area (also called biodiversity)
Ecosystem diversity- variety of habitats and ecological processes w/in an ecosystem
Genetic diversity-different genes contained w/in all members of a population Gene- piece of DNA that codes for specific trait,
that could be inherited by offspring
Preserving ecosystem balance Keystone species- species that are critical
to the functioning of an ecosystem We depend on healthy ecosystem to ensure a
healthy biosphere
Genetic diversity within populations are critical to species survival
Diversity comes from large populations
Bottleneck effect- population shrinks due to sudden event
(natural disaster, human influence) leaving only a few
members thus reducing genetic diversity
Practical uses of species Clothing Shelter Medicine
¼ prescription drugs plants
Antibiotics fungi Food
Most new foods are hybrids- crops created by combining genetic information from various species
Aesthetic value or personal enjoyment Ecotourism- business that supports the
conservation and sustainable development of ecologically unique areas
Ethics Belief of some that species and ecosystems have
right to exist, regardless of their value
Species at risk• Species w/small populations• Migratory species• Those that need large tracts of land• Those exploited by humans
Endangered- likely to go extinct if protective measures are not taken immediately
Threatened- declining population and is likely to become endangered if it is not protected
Habitat Destruction & fragmentation Invasive exotic species
Exotic species- species not native to a particular area
Poaching- illegally hunting, fishing, harvesting, or trading wildlife
Pollution
Endemic species- species that are native to and found only within a limited area Tropical Rain Forest Coral Reefs & Coastal Ecosystems Islands
Most threatened areas of high species diversity on Earth