Chapter 21

What are the different ways of measuring biodiversity?

The number of species and the number of individuals in each of these species

How many species have been described? How many are likely to exist?

Scientists have described around 1.5 million species, but estimates of the total number range from 3 to 100 million.

What are the primary threats to biodiversity? Give examples of each.

Habitat loss- humans want palm trees for palm oil, so they cut down local trees to grow palm trees, destroying the habitat where those animals live

Overharvesting - fisheries: humans overfish to the point where there is barely any fish left.

Introduction of exotic species- increased mobility & trade, an example is zebra mussels

What is the ‘tragedy of the commons’?

Resources held in common (area) will inevitably be overexploited, if everyone takes more than their share, then there isn't any more for anyone.

Why are most extinctions “invisible”?

That most extinctions are probably happening without being observed

What are some important considerations for designing conservation areas? What are some of the challenges?

Large reserves support more species, offer optimal habitat, provide more niches, and attract more species, making them more effective for conservation.

Define biodiversity hotspot. Do you think this designation is the best way to protect biodiversity? Why or why not?

Areas that contain high numbers of species

Yes, this is the best way so far to protect biodiversity because it makes sure that human aren’t going to destroy the environment and species of this area so they can naturally go through their life cycle and learn natural instincts.