Biology Now, 2e

Of Wolves and Trees ■ 375

Human

Leopard

seal

Carnivorous

plankton

Elephant

seal

Sperm

whale

Other

herbivorous

plankton

Squid

Penguin

Baleen whale

Phytoplankton

(producer)

Krill

(primary

consumer)

Killer whale

(tertiary or quater-

nary consumer)

Chilean sea

bass

Crabeater seal

(secondary

consumer)

(^11) Rabbits can eat many plants, but they prefer some plants
over others. Assume that the rabbits in a grassland community
containing many plant species prefer to eat a species of grass that
happens to be a superior competitor. If the rabbits are removed from
the region, predict whether relative species abundance will increase
or decrease, and whether species richess will increase or decrease.
(^12) Identify whether each of the following is an example of primary
succession (P) or secondary succession (S) in Rocky Mountain
National Park.
a. A mountain slope was cleared of evergreen trees and is
now sprouting aspen trees.
b. A mountainside with mature evergreen trees has domi-
nated the landscape for generations.
c. An area of soil, sand, and rocks remains after a dam burst
and flooded the area.
d. Lichens and mosses grow on bare rock at upper elevations
because of an increase in average yearly temperatures.
(^13) Analyze the food web shown in the accompanying figure and
answer the following questions:
a. Which species do not have a predator shown on the food web?
b. Which species shown on the food web performs photosynthesis
(captures light energy to make its own food)?
c. Which species have only one predator and only one prey shown
on the web?
d. Which species has the most predators shown on the web?
Leveling Up
(^14) Doing science Citizen science is an amazing way for anyone
to get involved in scientific research. Search the Internet for
citizen science projects relevant to this chapter’s topics, using
keywords like “parasite,” “predator,” “prey,” and “group living,” to
name a few. Examples include Project Monarch Health (http://www
.monarchparasites.org), in which volunteers sample wild monarch
butterflies for a protozoan parasite to track its prevalence across
North America. Participate in a project and, in writing, reflect on
what you learned.
(^15) Write Now biology: saving a species Write a letter to your
congressperson in which you use the concepts learned in this
chapter to explain how wolves (or a different species near you)
are beneficial to our wilderness ecosystems. Explain what role
the species plays in the environment, what has caused it to be
endangered or at risk now, what the likely effect will be if it goes
extinct (locally or globally), and what could be done to ensure
its survival.
For more, visit digital.wwnorton.com/bionow2 for access to:
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