20 most important things to know about species and the loss of biodiversity
1. Human activity has completely altered, disturbed, or degraded 50% of the earth’s land surface.
2. Presently,
the earth is experiencing its sixth great mass extinction event, caused not by
volcanoes or asteroids as in the past, but by human
activity.
3. Percentage of major organism
categories under the threat of extinction worldwide: plants (14%), fish (34% of
all fish;
51% of freshwater fish), amphibians (25%), reptiles (20%), birds (12%),
and mammals (24%).
4. About 33% of the animal and plant species in the United States are vulnerable to premature extinction.
5. Over 50% of the original wetlands in the United States have been destroyed by human activity (91% in California)
6. There are probably somewhere between 5 to 20 million species on earth with about 1.4 to 1.8 million having been identified.
7. The major causes of species
extinction are the following:
a) habitat destruction or
degradation (primary cause of extinction)
b) introduction of non-native,
invasive species into ecosystems (second leading cause of extinction)
c) climate change-global
warming
d) illegal hunting, poaching,
and collecting
e) air, soil, and water
pollution
8. Extinction can take place on
three levels:
a) local extinction – a species
is extinct in a specific area but not worldwide
b) ecological extinction – a
species numbers have been reduced to the extent that it no longer plays a
significant ecological role
c) biological extinction – all
members of the species are gone worldwide
9. Scientists estimate that the
present worldwide extinction rate ranges between 1,000 to 75,000 species per
year ( 3 to 200 species
per day worldwide)
10. Species can be classified according to the
scarcity of its individual members into the following five categories: common,
rare,
threatened, endangered, extinct.
11. 5.9% of the earth’s total land area has been protected from development
12. 50% of the earth’s tropical rainforests have been destroyed; 15 to 20 million hectares per year continue to be lost.
13. The Theory of Island
Biogeography states that the larger an ecosystem or habitat is, the greater the
biodiversity that it will
support.
Fragmenting habitats into small pieces reduces biodiversity.
14. Why do we need to save species?
a) because they provide us with
a wide variety of economic goods
b) because they are the source
of our food crops
c) because they contain a vast
amount of genetic information that has evolved over millions of years
d) because they are source of a
large percentage of our medicines
e) because they are used in
scientific studies throughout the world
f) because they provide us with
recreation (hunting, birding, fishing, photography)
g) they are important for the
ecotourism industry
h) because all living things
have a right to exist (intrinsic value)
i) because they provide us with
beauty and something to appreciate
j) future generations of
mankind have a right to appreciate and use them
k) because they provide us with
ecological services (photosynthesis, pollination)
15. Characteristics that make a
species vulnerable to extinction:
a) low reproduction rates,
examples include the panda bear, manatee, and Calif. condor
b) found in only one small
area, not widespread
c) specialized feeding habits
(eats only one or two types of food)
d) specialized breeding and
reproduction areas (for example, sea turtles only lay their eggs on certain
e) high trophic level feeders –
animals at the top of the food chain
f) animals or plants that have
a specialized niche
g) low population density which
reduces mating activity (e.g. blue whale)
h) species that interfere with
human activity (e.g. wolves)
i) large size which can make a
species a more visible target or more commercially valuable.
16. What can be done to save
species?
a) save habitat by establishing
or enlarging parks, wildlife preserves, and wilderness areas
b) regulate privately owned land
c) pass laws to protect species
d) reduce human population growth and consumption
e) restore damaged habitats and reforest damaged forest areas
f) establish captive breeding programs and seed banks
g) educate the public on how to care for and protect the environment
h) reduce and control pollution
i) reduce the effects of global warming and ozone depletion
j) prevent the establishment of non-native, invasive species into ecosystems
17. What are important pieces of
legislation that help to protect species?
a) Endangered Species Act
(1973) – protects species in danger of becoming extinct
b) C.I.T.E.S. Treaty (1975) International treaty that protects species throughout the world
c) Lacey Act (1900) – prohibits transporting wild animals across state boundaries
d) Wilderness Act (1964) –
preserves wilderness habitats permanently
18. The three most biologically
productive and species rich areas on earth are the tropical rainforests,
wetlands, and coral reefs. It is
estimated that at least 40% of all species are found within the tropical rain
forests.
19. It is important that private
land owners work with conservationists to save species and habitat because over
55% of the land in
the U.S. is privately owned.
20. Notable endangered species
include: the California Condor, both Elephant species, Cheetahs, Indian Tiger,
Black Rhino, Panda
Bear, Mountain Gorilla, Desert Tortoise, Florida Manatee,
Spotted Owl, Florida Panther, all Sea Turtles, and the Blue Whale.