LESSON PLAN G -- (ADDRESSES C.2.5 [State and explain
the criteria used to determine a specie’s conservation status.] &
C.2.6 [Describe the case histories of three species: one that has
become extinct, another that is currently endangered, and a
third that was endangered and has now been removed from the
endangered list.])
1) DISCUSSION on “Specie’s conservation status”. See if students
can match the correct definition with the conservation status. [Read the
definition slowly and have the students match that definition with the
status terms written on the dry-erase board [write the terms on the board
in a random order]. Then, write the terms on the board in order of
severity of situation (worst to best): EXTINCTION, EXTINCTION IN
THE WILD (you could perhaps find that organism in a zoo or botanical
garden), CRITICALLY ENDANGERED, ENDANGERED,
VULNERABLE.
2) Refer to C.2.6 for this part of the LP. Have students break up into
pairs (each with 1 organism). The students in each group need to
review the case history of the organism (take notes on a piece of paper
because the card with the photo will circulate around the room) and give
a short presentation on that case history. [All students will memorize
their part/parts of the presentation and not merely read from notes.]
What’s involved in a case history:
--What is the conservation status of assigned organism?
--What are the causes for its decline in nature?
--What is the ecological significance of the organism in its
ecosystem? [Only mention this if it’s discussed in the case
history.]
BACKGROUND ON C.2.5:
Students should know criteria by which species are placed in the unknown,
rare, vulnerable, endangered and extinct categories in the red data books.
(The IUCN [International Union for Conservation of Nature] Red List is
available for each country.) Use evolutionary and ecological significance of
species as criteria for determining conservation status.
UNKNOWN: Insufficiently known. Species that are suspected but not
definitely known to belong to any of the above categories, because of lack of
information
RARE: Rare. Not under immediate threat of extinction, but occurring in such
small numbers and/or in such a restricted or specialized habitat that it could
quickly disappear. Requires careful watching. Rare. Species with small world
populations that are not at present 'Endangered' or 'Vulnerable', but are at risk.
These species are usually localised within restricted geographical areas or
habitats or are thinly scattered over a more extensive range.
VULNERABLE: Vulnerable. Species believed likely to move into the
'Endangered' category in the near future if the causal factors continue
operating. Included are species of which most or all the populations are
decreasing because of over-exploitation, extensive destruction of habitat or
other environmental disturbance; species with populations that have been
seriously depleted and whose ultimate security has not yet been assured; and
species with populations that are still abundant but are under threat from
severe adverse factors throughout their range. Facing a high risk of extinction
in the wild; based on a population reduction of 30 percent or more, a range
reduced to 20,000 square kilometers (7,722 square miles) or less, or a 10
percent probability of extinction within 100 years (among other criteria).
ENDANGERED: Under the Endangered Species Act of 1973 "the term
'endangered species' means any species which is in danger of extinction
throughout all or a significant portion of its range (other than a species of the
Class Insecta determined by the Secretary to constitute a pest whose
protection under the provisions of this Act would present an overwhelming
and overriding risk to man). http://eelink.net/EndSpp/endangeredspeciesdefinitions.html
Facing a very high risk of extinction in the wild; based on a population
reduction of 50 percent or more, a range reduced to 5,000 square kilometers
(1,930 square miles) or less, or a 20 percent probability of extinction within
20 years (among other criteria). http://www.sandiegozoo.org/animalbytes/astatus.html
Critically endangered— Facing an extremely high risk of extinction in
the wild; based on a population reduction of 80 percent or more, a range
reduced to 100 square kilometers (38.6 square miles) or less, or a 50
percent probability of extinction within 10 years (among other criteria).
EXTINCT: Extinct. Species not definitely located in the wild during the past
50 years. No reasonable doubt that the last individual has died.
Extinct in the wild— Known only to survive in captivity or in an
introduced population well outside the natural range.
BACKGROUND ON C.2.6:
From the WWF website which is:
http://www.worldwildlife.org/endangered/whatis.cfm
What is the definition of an endangered species?
WWF doesn't determine which species are considered endangered. The
IUCN (the World Conservation Union) is the organization that WWF and
other conservation groups, government agencies, scientists and academics
look to for that information. IUCN brings together the world's leading
scientists, including those from WWF, to assess the conservation status of
species, subspecies, varieties and subpopulations on a global scale,
highlighting species threatened with extinction and promoting their
conservation.
IUCN maintains a complete list of all the species it considers critically
endangered, endangered or vulnerable: It's called the Red List of
Threatened Species and can be found at www.redlist.org.
http://www.biodiversityhotspots.org/xp/Hotspots/tumbes_choco/
From the WWF website (information about the conservation status of
marine turtles):
Having traveled the seas for over 100 million years, marine turtles have
outlived almost all of the prehistoric animals with which they once
shared the planet. Marine turtles survived the extinction of the dinosaurs
and are still present in the world's oceans today.
Until recently, their success was apparent, as marine turtles crawled
ashore to nest in abundance on tropical and subtropical beaches around
the globe. Unfortunately threats like hunting for meat, shell and eggs;
habitat destruction; fisheries bycatch; pollution; boat strikes; and
introduced predators have wiped out entire turtle populations, or
reduced them to mere shadows of their former glory. Today 3 of the 7
existing species are critically endangered with extinction, three are
endangered and the status of the seventh species remains unknown.
http://training.fws.gov/deo/endang/sml/sld10.html
There are many different reasons why plants and animals become
endangered or threatened. The biggest reason is loss of their homes or
habitats. Habitat loss happens as more and more people move into new
areas and push wildlife out. Illegal or unregulated killing of animals and
overcollection of plants may also cause a species to become
endangered. Other reasons why endangered species are in trouble are
because of pesticides and pollution, competition with other non-native
species in their habitat, diseases, and predation.
All living things are connected to each other including humans. It is like
a web. The more we learn about the "web of life" the more connections
we discover. We are quickly learning that when we remove anything in
nature, something else is affected.
Living things all depend on each other, from the plants to the fish, to the
birds and eventually to humans. This system of living things depending
on one another is called an ecosystem. When an ecosystem has enough
living things in it to support itself in a healthy balance, it has enough
natural diversity.
Scientific research has worked well in many cases, and some
endangered species have come back.
The American alligator is an example of a success story. Unregulated
killing for the exotic leather trade threatened this reptile with extinction.
In 1987, it was taken off the endangered species list, due to the efforts
of many agencies working together to save it from over exploitation.
http://library.thinkquest.org/25014/english.index.shtml
Just how fast are species really disappearing? A biologist at Harvard
University named E.O. Wilson believes at least 4,000 to 6,000 species
become extinct each year as a result of the destruction of the tropical
rainforest alone. He thinks the actual worldwide extinction rate could be
much higher.
EXTINCT example:
The Fabulous Green Sphinx Moth (Tinostoma smaragditis) was listed as
Extinct in 1996, but in February 1998 a single male was attracted to a light trap
on its home island of Kauai, Hawaii. Since 1998, further individuals have been
trapped, but the species is listed as Endangered due to the impacts of invasive
species on its habitat. Photo © Mandy Heddle.
Paretroplus menarambo is a freshwater fish endemic to Madagascar and
epitomizes captive breeding efforts to save threatened Malagasy fish. The last
reports of this species in the wild were in the late 1990s and it is now listed as
Extinct in the Wild. However, breeding populations are maintained in captivity
thanks to animals collected in 1993 and shipped back to Old World Exotic Fish
in Homestead, Florida, USA. The main causes for the loss of this species were
deforestation, which had a detrimental effect on the species freshwater
habitat, introduced alien species, and overfishing. Photo © Paul Loiselle.
The Hawaiian Crow (Corvus hawaiiensis) is now listed as Extinct in the Wild
after the last two known wild individuals disappeared from Hawaii in 2002.
Habitat alteration, collecting and shooting, introduced predators (e.g., rats, the
Indian mongoose) and predation from the native Hawaiian Hawk, and avian
malaria and pox carried by introduced mosquitoes have contributed to the
crow’s decline. Some individuals remain in captive breeding facilities and a
reintroduction plan is being developed. Photo © Jack Jeffrey Photography.
Scimitar-horned Oryx (Oryx dammah) was once one of the most common
large mammals of northern Africa. Overhunting for the animal’s meat, hide and
magnificent horns, combined with habitat loss and caused major declines in
the species and by the end of the 20th century none were known to remain in
the wild. Currently listed as Extinct in the Wild, the species is now part of a
major captive breeding and reintroduction programme. Photo © Antonio di
Croce.
Black-footed Ferret (Mustela nigripes) is currently listed as Extinct in the
Wild, pending reassessment. This ferret is one of North America’s rarest
mammals and it depends on an endangered ecosystem for survival. The
population declined throughout the 1900s and in 1985, the last known freeranging population collapsed due to an outbreak of canine distemper and the
species was considered Extinct in the Wild. Through a successful captive
breeding and re-introduction programme, Black-footed Ferrets are making a
come-back. Photo © Dean Biggins.
ENDANGERED example: Sloth and Giant Anteater
http://sokagakkai.info/html3/viewpoint3/today3/amazon3.html
Galapagos Giant Tortoise
Populations (of Galapagos Giant Tortoises), particularly on the more
accessible islands, were severely depleted by passing ships (particularly
whalers) taking tortoises on board for supplies. A total of over 15,000
tortoises are recorded in the logs of 105 whaling ships between 1811
and 1844 (12). Increased settlement in the 20th century encouraged
commercial hunting of tortoises for oil and extensive collecting for
museums (3). Introduced mammals now pose the greatest threat to the
tortoises. Feral pigs, dogs, cats and black rats are extremely effective
predators whilst feral goats, donkeys and cattle compete for grazing.
Goats have had particularly drastic effects upon the natural vegetation
(6).
http://www.discovergalapagos.com/tortoise.html#BREEDING
Bulimulus ochsneri is one of the many threatened terrestrial snails from the
Galapagos Islands. Listed as Critically Endangered, Bulimulus ochsneri is
endemic to Santa Cruz. The range of suitable habitat for land snails on Santa
Cruz Island has declined because of human activities (farming, road and
house construction, etc.) and destruction or alteration by introduced species.
Photo © Christine Parent.
Siphocampylus ecuadoriensis is an Endangered shrub. It is found only in
Ecuador where it is known from nine subpopulations in the Andes. One
subpopulation in the surroundings of the Papallacta-Cuyuja road faces a high
risk of extinction, due to the ongoing conversion of native vegetation to
pasture. Although the plant grows inside a protected area, deforestation still
threatens the species. Photo © Suzanna León-Yánez.
Centropogon erythraeus is assessed as Endangered based on its restricted
range and decline. This shrub is endemic to Ecuador where it is known from
two subpopulations in the southern Andes. The species is locally abundant in
the Loja-Zamora road on the southern border in the Parque Nacional
Podocarpus where it forms part of the pioneer vegetation on the roadsides.
Photo © Suzanna León-Yánez.
Mutisia magnifica is a Vulnerable vine endemic to Ecuador. The species is
found in vegetation remnants, which are seriously threatened by wood
extraction for charcoal production. Photo © Carmen Ulloa.
Slender Seahorse (Hippocampus reidi), listed as Vulnerable, is found in the
western Atlantic waters of the Caribbean and Central and Southern America.
Unsustainable levels of harvest seriously threaten this species as it is caught
and sold dried as tourist souvenirs, with live animals entering the aquarium pet
trade. International trade in seahorses for use in traditional medicines is also a
major threat. Reports from fishermen in the area indicate that numbers of H.
reidi in the wild are decreasing. Photo © Shedd Aquarium (photo by Edward
G. Lines, Jr.).
Golden Lion Tamarin (Leontopithecus rosalia) is endemic to Brazil. The
species moved from Critically Endangered down to Endangered after nearly
30 years of conservation efforts resulted in a population increase. There are
now estimated to be more than 1,000 individuals. There is little room for
further expansion of the wild population, however, considering the extreme
fragmentation and reduced forest cover within its range. Current and future
conservation efforts are tackling this problem with reforestation and the
establishment of habitat corridors. Photo © Juan Pratginestós/WWF-Brasil.
Yellow-eared Parrot (Ognorhynchus icterotis) is Critically Endangered
because its known range (especially the nesting area) is extremely small.
Suitable habitat is severely fragmented throughout its historical range and
continues to be lost and degraded. Currently, it is known only to remain in
the Central Andes of Colombia. Conservation action is addressing some of
the key issues but the future of this species remains extremely uncertain.
Photo © Fundacion ProAves (c/o Paul Salaman).
WAS ENDANGERED BUT NOW REMOVED FROM LIST example:
Bald Eagle
DDT is an insecticide (DDT) that was used all over the U.S.. It was
found in water & soil and eventually worked its way up the food chain
from small water feeders to the fish who ate the plant life in the water
and the animals and humans who ate the fish! When DDT was left into
the water it eventually broke down and became DDE. These toxic
substances (along with others like PCB's) caused eagles and peregrine
falcons to produce eggs that had shells so thin that they broke just from
the mother sitting on them. For years the bald eagle was listed as
endangered under the Endangered Species Act. Now the number of bald
eagles has increased so much that in June, 1994 the U.S. Fish and
Wildlife Service proposed that they be downgraded from endangered
status to the less urgent status of threatened in all but three of the lower
48 states. The success of the bald eagle is a tribute to the Endangered
Species Act and is an incentive for increased awareness and
conservation everywhere. [Bald eagles are a very important part of the
environment. By eating dead animal matter, they help with nature's
clean-up process. Bald eagles are also hunters, so they keep animal
populations strong. They do this by killing weak, old, and slower
animals, leaving only the healthiest to survive.]
Students should know the ecological, socio-political and economic pressures that caused
or are causing the chosen species’ extinction. The species’ ecological roles and the
possible consequences of their disappearance should be understood.