True or false chapter 7

A threatened species faces a greater chance of extinction than an endangered species

False

In the past, earth has experienced only one mass extinction

False

It has not been possible to get countries to agree to participate in any international treaties that protect threatened and endangered species

False

Scientific evidence indicates that extinction rates in the past few centuries have risen mainly due to natural causes

False

Captive breeding populations need a population of at least 100 individuals to maintain enough genetic diversity for the species to survive

False/true

Due to biomagnification, a pollutant becomes more concentrated within the tissues of organisms at higher trophic levels

True

Many of the worlds species provide valuable ecosystem and economic services such as pollination of crops

True

Projected extinction rates may be underestimated due to ongoing impacts of a growing human population and environmental degradation

True

Seed banks are facilities used to safely store plant samples so they are available for future use

True

Some introductions of nonnative species have been beneficial to humans

True

The us endangered species act is likely the most successful environmental law of any country

True

habitat fragmentation can cause species to become more vulnerable to predators, competitor species, disease, and catastrophic events

True

habitat loss, degradation, and fragmentation are the greatest threats to wild species

True

illegal hunting of exotic animals is an example of overexploration

True

wildlife refuges have been successful at protecting species from extinction

True