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Chapter 10: What is Biodiversity


Biodiversity – the number and variety of species in a given area


The study of biodiversity starts with cataloging all the species that exist on earth

-    Known species – collected and described scientifically

-     Unknown species – exist in remote wilderness, deep oceans, cities.


Some types of species are harder to study and get less attention than large, familiar species


Biodiversity can be studied and described at 3 levels:

      1.  species diversity – all the differences between populations of species, and between different species.

2.  ecosystem diversity – the different habitats, communities, and ecological   processes within and between ecosystems

3.  genetic diversity – all the different genes contained within all members of a population’s gene pool – DNA that codes for a specific trait


Benefits of biodiversity

  1. everything is connected – the presence of different species keeps things in balance.  The species depends on things and things depend on it.  If one species is removed, multiple other species are affected.  Things are thrown out of balance.
    • Keystone species – species that are critical to an ecosystem
  2. genetic diversity – the more genetic diversity there is the better the chance that a species will do well.  Increases chance of survival. Genetic bottlenecks are bad – reduced genetic variation.
  3. medical, industrial, and agricultural uses.  Medicines come from plants, potential new products for industry, food and new crop varieties.  The Irish potato famine happened b/c of lack of biodiversity.
  4. ethics (b/c it’s the right thing to do), aesthetics (personal enjoyment), recreation (ecotourism)



Mass extinction – extinction of many species in a short period of time (ex: the dinosaurs)

We may be in a mass extinction – but it’s different from before, b/c this time humans are the primary cause


Certain species are prone to extinction

-   Roaches and rats are not – they are large pops that can survive easily to many different habitats

-  Species with small populations in limited areas are more prone to extinction.

-  Species especially at risk are: 1) species that migrate 2)need large, special habitats 3) exploited by humans


Endangered species – likely to become extinct if protective measures are not taken immediately


Threatened species – species with a declining population that is likely to become endangered if it is not protected


4 main ways humans cause extinctions:

1.  habitat destruction – as human populations grow we use more land to build homes and use resources.  In the process we destroy and break up the habitats of other species

2.   introduction of non-native speciesexotic species = species that is not native to a particular place.  Exotic species can threaten native species that have no natural defenses against them.

3. over-harvesting and hunting – can push the species to such low numbers that they go extinct.  Many countries have laws to regulate it.  Poaching – when it continues illegally.

4. pollution – pesticides, cleaners, drugs, chemicals made by humans are making their way into food webs.


Areas of critical biodiversity have endemic species.

endemic species =  species that are native to and found only within a limited area



3 areas of critical biodiversity: (Areas with high biodiversity and large number of endemic species)

1.                  tropical rain forests – cover only 7% of the world but over half the world’s species live there

2.                  coral reefs and coastal ecosystems – contain the majority of marine biodiversity

3.                  islands – have limited but distinct sets of species since islands are isolated


biodiversity hotspot – the most threatened areas of high species diversity

they have high numbers of endemic species but are threatened by human activities





We are making efforts to slow the loss of species and conserve the ecosystem


4 ways we are trying to save species (one species at a time):


1.  Captive breeding programs

breeding species in captivity with the hope of re-introducing populations to their natural habitats.  The big question is whether restored populations will ever reproduce in the wild

2.  Preserving genetic material

saving the essence of a species – the essence of a species is its genes.  They do it by making germ plasm banks (germ plasm = genetic material from the reproductive cells of animals – seeds, sperm, eggs, or pure DNA).  They store it so it can be used in the future.

3.   Zoos, aquariums, parks, gardens

Living museums of biodiversity.  These started as a way to display exotic species… now places like these house the few remaining members of a species and could be the species last hope for survival.

4.  Making protective laws


Problems – captive species may not reproduce in the wild.  Small populations are susceptible to infectious disease and genetic disorders from inbreeding.


The best thing to do is preserve whole habitats and ecosystems – not just single species.

-                     Since everything is connected – Protecting entire ecosystems may help save many more species and will maintain ecosystem functions.

-                     How – identify native habitats that can be preserved, restored and linked to large networks. 

-                     Promote products that have been harvested/produced with sustainable practices



Legal protections

US has some of the strongest laws to protect species from becoming extinct


Endangered Species Act of 1973 has 4 main parts:

-                    US fish and wildlife service has to make a list of all the endangered and threatened species

-                     Endangered/threatened species may not be caught or killed. Endangered/threatened plants may not be uprooted.  No part of an endangered/threatened species may be sold or traded

-                     The federal government may not carry out any project that jeopardizes endangered species

-                     The USFWS must make a species recovery plan for each endangered/threatened species.

A.     Species recovery plans often propose to protect or restore habitat

B.     Controversial to restrict human use of land (when developers are restricted from building on their own land b/c such species live there)

C.     Habitat conservation plan – attempts to protect species and areas of land through trade-offs and cooperative agreements


International cooperation

-           International Union for the Conservation of Nature and Natural Resources (IUCN)

Makes “red lists” of species in trouble and advises governments on ways to manage their national resources and works with wildlife groups

-           CITIES treaty – Convention on International Trade in Endangered Species

Started to stop elephant killing and ivory trade

-           Biodiversity treaty – has the goal to preserve biodiversity and ensure the sustainable and fair use of genetic resources in all countries

-           Private conservation efforts like World Wildlife Fund and Greenpeace



A)There are 3 ways to deal with problems:

1)      Prevention (Easiest and cheapest way to solve a problem; also it is effective)  

a.       Moral: Teaching people right and wrong; and justice

b.      Law: Establishing preventive law

2)      Deterrence

3)      Treatment (most expensive)

B) When addressing a problem identify the root of the problem. The resources are limited, therefore we must identify key, hotspot areas that central to the problem. Taking preventive action in these areas will bring us maximum benefit. (ex: identify the streets in which most car accidents happens in a city than take preventive action in these key areas by build bumps, traffic light, and placing police) Don't chase away flies when you are surrounded with wolves.
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Feb 11, 2010, 2:56 AM