The treeʹs horizontal axis is a timeline that extends from 100,000 years ago to the present; the vertical axis represents nothing in particular. The labeled branch points on the tree (V—Z) represent various common ancestors. Letʹs say that only since 50,000 years ago has there been enough variation between the lineages depicted here to separate them into distinct species, and only the tips of the lineages on this tree represent distinct species.

How many separate species, both extant and extinct, are depicted in this tree?

#Question id: 11714

#Section 2: Evolution

In recognizing patchiness in the natural world, ecologists have developed three different models of populations. Which of these recognize(s) that there are differences in the quality of habitat patches without considering effects of differences in habitat quality within the habitat matrix?

#Question id: 11715

#Section 2: Evolution

The lifetime dispersal area of a particular species of drosophila is 0.2 km2. What else would we need to know to determine the neighbourhood size for this species?

#Question id: 11716

#Section 2: Evolution

Macroecology addresses patterns of range size and population density. Which of the following statements is true?

#Question id: 11765

#Section 2: Evolution

The population density of a particular insect species was determined to be 15,000 adults per hectare in the summer of 1996, 21,000 adults per hectare in the summer of 1997, and 29,400 adults per hectare in the summer of 1998. Based on these population estimates, what is your estimate of λ, the annual rate of geometric growth?

#Question id: 11766

#Section 2: Evolution

The population density of a particular insect species was determined to be 15,000 adults per hectare in the summer of 1996, 21,000 adults per hectare in the summer of 1997, and 29,400 adults per hectare in the summer of 1998.

What would you expect the insect population to be in the summer of 2000, assuming no change in λ?

#Question id: 11767

#Section 2: Evolution

If a population has a stable age distribution, which of the following statements is true?