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By the end of this section, you will be able to:
  • Identify significant threats to biodiversity
  • Explain the effects of habitat loss, exotic species, and hunting on biodiversity
  • Identify the early and predicted effects of climate change on biodiversity

The core threat to biodiversity on the planet, and therefore a threat to human welfare, is the combination of human population growth and resource exploitation. The human population requires resources to survive and grow, and those resources are being removed unsustainably from the environment. The three greatest proximate threats to biodiversity are habitat loss, overharvesting, and introduction of exotic species. The first two of these are a direct result of human population growth and resource use. The third results from increased mobility and trade. A fourth major cause of extinction, anthropogenic climate change, has not yet had a large impact, but it is predicted to become significant during this century. Global climate change is also a consequence of human population needs for energy and the use of fossil fuels to meet those needs ( [link] ). Environmental issues, such as toxic pollution, have specific targeted effects on species, but they are not generally seen as threats at the magnitude of the others.

 The graph plots atmospheric carbon dioxide concentration in parts per million over time (years before present). Historically, carbon dioxide levels have fluctuated in a cyclical manner, from about 280 parts per million at the peak to about 180 parts per million at the low point. This cycle repeated every one hundred thousand years or so, from about 425,000 years ago until recently. Prior to the industrial revolution, the atmospheric carbon dioxide concentration was at a low point in the cycle. Since then the carbon dioxide level has rapidly climbed to its current level of 395 parts per million. This carbon dioxide level is far higher than any previously recorded levels.
Atmospheric carbon dioxide levels fluctuate in a cyclical manner. However, the burning of fossil fuels in recent history has caused a dramatic increase in the levels of carbon dioxide in the Earth’s atmosphere, which have now reached levels never before seen in human history. Scientists predict that the addition of this “greenhouse gas” to the atmosphere is resulting in climate change that will significantly impact biodiversity in the coming century.

Habitat loss

Humans rely on technology to modify their environment and replace certain functions that were once performed by the natural ecosystem. Other species cannot do this. Elimination of their ecosystem—whether it is a forest, a desert, a grassland, a freshwater estuarine, or a marine environment—will kill the individuals in the species. Remove the entire habitat within the range of a species and, unless they are one of the few species that do well in human-built environments, the species will become extinct. Human destruction of habitats accelerated in the latter half of the twentieth century. Consider the exceptional biodiversity of Sumatra: it is home to one species of orangutan, a species of critically endangered elephant, and the Sumatran tiger, but half of Sumatra’s forest is now gone. The neighboring island of Borneo, home to the other species of orangutan, has lost a similar area of forest. Forest loss continues in protected areas of Borneo. The orangutan in Borneo is listed as endangered by the International Union for Conservation of Nature (IUCN), but it is simply the most visible of thousands of species that will not survive the disappearance of the forests of Borneo. The forests are removed for timber and to plant palm oil plantations ( [link] ). Palm oil is used in many products including food products, cosmetics, and biodiesel in Europe. A five-year estimate of global forest cover loss for the years 2000–2005 was 3.1 percent. In the humid tropics where forest loss is primarily from timber extraction, 272,000 km 2 was lost out of a global total of 11,564,000 km 2 (or 2.4 percent). In the tropics, these losses certainly also represent the extinction of species because of high levels of endemism.

Questions & Answers

What is demand
TECK Reply
the amount of a good that buyers are willing and able to purchase
Asit
what is population
Amadou Reply
The people living within a political or geographical boundary.
Ziyodilla
what happens to price and quantity when demand curves shift to the right
Asha Reply
price level goes up. quantity demand increases
Asit
example- inferior goods
Asit
demand law
Athony
Its states that higher the price the of the commodity, and lower the quantity demanded
Kosiso
I am confused but quantity demand will increase.
Asit
No. That's the law of supply
Kosiso
what happens to price and quantity when supply curve shifts left?
Asha Reply
price level will increase
Asit
quantity demand will decrease
Asit
what is inflation
Pop Reply
inflation is a general and ongoing rise in the level of prices in an entire economy.
cynthia
is the pasistance increase in the price of a country economy
Liyu
kk
Duppy
yes
Aadi
how does inflation affects the economy of a country? what is deflation?
Augustine
deflation can simply be define as the persistence decrease in price of a countrys economy
Liyu
the revenge of malthus relates "revenge" with "commodity prices". collect data for 3 commodoties and check their price evolution
Jamshi Reply
what is elasticity
dubela Reply
Elasticity is an economics concept that measures responsiveness of one variable to changes in another variable.
cynthia
right
Augustine
wooow!!
cynthia
Computer software represents
Mboledi Reply
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plz Reply
Hey what are you trying to mean?
Kenyana
what is Asset
MUBARAK
like a banana
Ahmed
demand is the process whereby consumers are willing and able to purchase a particular product at various price over a given period of time
Samuel Reply
The law of dinimish
Frank Reply
What is the law of dinimish
Frank
What is the law of dinimish
Frank
What is the law of dinimish
Frank
opportunity cost is to forgo something for another.
jackie Reply
yes
King
what is financial market
Asheeru Reply
what is demand
Levinel Reply
Demand is an economic principle referring to a consumer's desire to purchase goods and services and willingness to pay a price for a specific good or service.
Ali
explain any three exceptions to the law of demand
Emma Reply
Difference between extinct and extici spicies
Amanpreet Reply
While the American heart association suggests that meditation might be used in conjunction with more traditional treatments as a way to manage hypertension
Beverly Reply
Which event leads to a diploid cell in a life cycle
Nicole Reply

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Source:  OpenStax, University of georgia biology. OpenStax CNX. Dec 09, 2013 Download for free at https://legacy.cnx.org/content/col11585/1.6
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