Environmental
number of species described in the world?
1.74 million
estimated number of species on the planet?
>13 million
top three animals with the most amount of species?
1. Insects 2. Arachnids 3. Mollusks
Top three plants?
1. Flowering plants 2. Mosses 3. Ferns
2 extinct birds
Dodo and Great Auk
two reasons why biodiversity is different today compared to the past
1. extinction 2. Adaptation, speciation events
Extinction is an ongoing process so it’s ______ but the pace of extinction is _______
1. natural 2. accelerating
In the last 500 years human activity is known to have forced this number of extinctions in the wild?
820
Of the extinction forced by human activities there are this # of animals and this # of plants?
726 animals ; ; ;90 Plants
Many of the forced extinctions occurred on
oceanic islands
Extinction rates are elevated over
geologic rates
# of bird species extinct per 100 years
25
# of mammal species extinct per 100 years
20
extinction is….
final (with out herculean efforts and biotechnology)
some species are more capable of becoming
extinct over others (attwater’s prairie chicken but not starlings)
IUCN
International Union for Conservation of Nature
IUCN’s Red List
Species threatened with extinction
Data for the Red List is collected about species _____ and _______
numbers and changes in numbers
Species being evaluated for the IUCN’s red list are evaluated on
the likelihood of surviving
The IUCN uses this to categorize each species
A decision tree
critical number
the minimum number of individuals of a given species that is required to maintain a healthy, viable population of the species (falls below critic. # its likely gonna be extinct)
Threatened species
population counts or estimates are below the critical number (critically endangered, endangered, and vulnerable)
__% of animals threatened globally
36
__% of global mammals threatened
21
__% of global birds threatened
12
__% of global amphibians threatened
30
Why are so many species recently extinct or threatened with extinction?
combo of circumstances: 1. small initial population 2. Reduction in numbers due to changes in environmental
Most species are rather specialized in their ________ _________ and ________ ______
feeding requirement and living conditions
5 Things that change in environment that lead to extinction?
1. Physical habitat alteration 2. Exotic species 3. Overexploitation 4. Pollution 5. Climate Changes
4 divisions of Physical Habitat Alteration that leads to extinction
1. Land conversion (farm replace forest) 2. Fragmentation (patches of suitable habitat unconnected) 3. Simplification (remove undesirable species and encourage desirable) 4. Intrusion (species contact)
Affects of Pollution when discussing extinction
1. Direct removal by poisoning 2. Indirect weakening of immune system
Climate changes causes problems because environmental shifts occur more rapidly then
adaptation ability
what fraction of all the worlds vertebrate species are under extinction?
1/5
one in _____ mammals are under the threat of extinction
four
one in ______ birds are under threat of extinction
eight
one in _____ reptiles are under threat of extinction
four
since elevated biodiversity loss is linked to ______ _______ it is significant that human _______ and _____ are projected to continue for the next century or two
1. human activity 2. growth 3. affluence
But is biodiversity loss really a problem? (corresponds to what hallmark)
5th hallmark; sustainability involves biodiversity
by losing biodiversity we lose the potential of new or improved?
foods and medicines
2 reduced ecosystem services that occur with loss of biodiversity
1. water purification 2. air replenishment
3 things can be done to slow biodiversity loss?
1. active preservation of habitats 2. Promotion of policies that reduce habitat loss 3. Restrict human activities that increase exploitation
Leave a Reply
Your email address will not be published.
*
*

BACK TO TOP