How can we help?

You can also find more resources in our Help Center.

Chapter 11: Biodiversity

We are usually referring to species diversity when we talk about biodiversity. However, genetic diversity is also important to ecological systems because diverse genes?
Are necessary for a population to evolve in changing environment.
Ecological diversity is a measure of the number of..
niches, trophic levels, and ecological processes of a biological community.
The common way that a species is defined in biology is in terms of reproductive isolation. This means that all organisms that are similar enough to
produce fertile offspring in nature
The underlying assumption with the reproductive isolation definition of a species is that __________________ prevents groups groups of similar organisms from exchanging genes.
reproductive isolation caused by geographic, physiology, or behavior.
You also mentioned to your friend that a new tool, DNA sequencing technology, is radically changing the way species are identify. In fact, some groups that were original thought to be far apart now seem to be closely related. Which of the following statements does not reflect the implications of using this new tool?
This tool will end the debate of what is or is not a species.
The total number of living species is probably
between 3 million and 50 million.
Approximately how many species have been identified on Earth?
a little less than 1.5 million
Most of the species that are yet undiscovered are probably..
invertebrates, bacteria, and fungi.
In the scenario above, which community has the highest species richness?
community a
Above, which communities have the same species evenness?
none of the communities have the same evenness
Above, which communities have the same species richness?
Community C and B
Above, if you walked through communities B and C, which one would seem to have more species richness?
Community C
One of the reasons humans rely heavily on only a few food crops is because
we have not explored the cultivation of thousands of edible wild species.
Which of the following is not benefit of biodiversity for humans?
unlimited opportunities for development
How is Costa Rica dealing with the problem of biodiversity for humans?
They are selling data and specimens to finance scientific work and biodiversity protection.
Which of the following drugs is not derived from a naturally occurring organisms?
An important drug for treating Hodgkin's disease was discovered in periwinkle native to _______ and is valued at approximately ________ per year.
Madagascar; 15 million
The pharmaceutical industry has an interest in preventing species extinction because
Undiscovered species may provide lucrative new drugs.
Soil formations and water purification are examples of ___________ based on the biodiversity that benefit humans.
ecological services
Which of the following is or would be an example of natural caused extinction
an insect species in the tropical forest that cannot escape predation by native bird species in the forest.
Extinction is the term used when all members of a species..
Which of the following is true?
Humans may have been causing extinctions thousands of years ago, but our impact has recently increased.
In General, an animal whose population is widely geographically is _____ as than one whose population is geographically restricted.
less likely to become extinct
Exotic is another word for
Introduced exotic species tend to _______ the balance of ecosystems and ______ biodiversity.
upset; decrease
The zebra mussel was introduced to the Great Lakes
accidentally in ocean going ship ballast
Which of the following would be a characteristic of an exotic plant species?
is an opportunist that is desired by humans for food or ornamental value.
Introduced disease organisms are especially dangerous to new environments because they destroy the non native host. This happens because the disease organisms..
have not evolved with this host to achieve the normal balance for long term success.
It is clear that a heavy dose of pesticides or other toxic pollutants seem to cause recent high mortality in marine mammals because
causing weakened immune systems and increased vulnerability to infection.
The US army participated in extermination of the American bison because
native peoples depended on the bison for food and shelter
Habitat fragmentation usually leads to a
decrease in biodiversity
The main reason for the current high rate of animal extinction is
habitat destruction worldwide
The drastic reduction in rhinoceros is due mostly to
the supposed medical value of their horns
Which of the following is not true of CITIES?
when implemented properly it has provided foolproof protections of endangered species.
The main reason for continued trade in endangered species is
pet lovers and collectors who like exotic species
If you have an aquarium with salt water fish, 75 percent of your fish probably came from..
wild fish populations caught with cyanide or nets.
Which of the following statements about trade in endangered species is false?
over harvesting affects animals more than plants.
A species in imminent danger of extinction is classified by the US endangered species act as..
Congress enacted the US Endangered Species Act in _____.
Canada's legal equivalent of the US Endangered species act is called the
Committee on the status of endangered wildlife in Canada
A species that is naturally rare or that has been depleted to dangerous levels is known, according to the endangered species act as a _____ species.
A threatened species may be extinct or near extinction
in the near future
The main reason that there are relatively few invertebrates categorized as endangered species because..
we consider other groups such as mammals to be more interesting and desirable.
In general, funding for recovery programs is given to species that are
most well known
The objective of a species recovery plan is to
increase an endangered species population until it is no longer endangered.
Conservationists and wildlife managers use gap analysis to
find unprotected landscapes that are rich in species.
When Aldo Leopold said the first rule to intelligent tinkering is to save all the pieces in terms of biodiversity he meant that we should
not cause species to disappear.
What type of correlation exists between the number of plant species in a plot and the change in biomass and what does this suggest?
positive; high levels of diversity yield higher levels of biomass.
Using the data from the figure above, arrange the degree of variability in biomass change from most variable to least variable.
1 species, 8 species, 5 species.