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Chapter 32 Nature's Wonderful Nature (2)
Salt-water communities are found in salt-water oceans and seas. Some communities are near the surface; others are in deep water. Living things in the sea are of three groups. Those which can swim strongly against a current include fish, squid, and whales. The second group is made up of all the plants and animals that live on the ocean floor. Here one will find such life as seaweed, crabs, and starfish. The third group is plankton which is the most important. Plankton are so small that they can be seen only with a microscope. Many sea animals depend on plankton for life.
Another type of community is the river community. A river provides a habitat for many kinds of living things. Plants, insects, and fish live in the water, on the surface, and on the riverbanks.
Field communities may be near rivers, or they may be fields that have never been upset by man, far from natural lakes or rivers. In the field communities one may find rabbits, chipmunks, and prairie dogs. The prairie dogs live in underground homes. They live in groups in homes that are like houses with many rooms.
The desert is a true community of many different plants and animals living together. Cactuses, mesquite, sagebrush, and wild flowers are a few of the plants that live in desert communities. Many mammals are found in desert communities such as jack rabbits, pack rats , prairie dogs, mule deer, and camels. Since these desert areas are very hot and dry, animals living there get most of their moisture form their food.
A forest is a very special kind of community. Here plants and animals live on three levels. The tree branches are at the top level, plants are at the middle level, and ferns and berries are found at the lower level. Among the forest dwellers You would find squirrels, chipmunks, porcupines, raccoons, and opossums. You might also find grouse, deer, foxes, and bears. Many kinds of birds, insects, and flowers inhabit the forest.
Vocabulary
biologist [bai"? l? d?ist] n. biologist
current ["k? r? nt] adj. current, current;
n. current, current, tendency
squid [skwid] n. squid, cuttlefish

whale [hweil] n. whale, whale

seaweed ["si:wi:d] n. Seaweed, seaweed

crab [kr? b] n. crab

starfish ["stɑ: fi?] n. Starfish (a marine animal)
Plankton ["pl??kt? n] n. Plankton
Habitat ["h? bit? t] n. (animal's) habitat, residence

riverbank ["riv? b?? k] n. River, river bank

upset[? p"set] vt. & vi. overturned;

vt. Disturb, distress;

n. Disturbance, discomfort;
adj. upset, uncomfortable
Chipmunk ["t?ipm??k] n. Chipmunk

prairie dog n.

Cactus ["k? kt? s] n. cactus, prickly pear
mesquite ["meski:t] leguminous plants
sagebrush ["seid? br??] n. Artemisia shrubs, Artemisia shrubs

jack rabbit n.

pack rat n. A person who refuses to throw anything away, a wood rat (or "collection rat")
mule deer n. Long-eared deer, black-tailed deer, moose

camel ["k? m? l] n. camel
Moisture ["m?ist??] n. Moisture, water vapor, moisture;
vt. make moisture-proof

fern [f? : n] n. <plant> fern, fern

berry ["beri] n. berry
Dweller ["dwel?] n. Dweller, resident

Squirrel ["skwir? l] n. Squirrel
Porcupine ["p?: kjupain] n. porcupine, porcupine

raccoon [r? "ku:n] n. raccoon, raccoon fur

opossum [? "p?s?m] n. A small marsupial with a curled tail, opossum

Grouse [ɡraus] n. grouse, grouse;

vi. to complain, to grumble
Practice
1. What are the six kinds of natural communities described in this text?

2. Match these words．

a. crab b． rabbit c． ferns d． starfish
A． forest community B． field community C． salt-water community
Translation
When we think of a community, we usually think of the town where people live.However, what biologists think of as a community is an environment in which plants and animals live together.Each organism has a role and is housed in ecological communities.

Marine communities exist in very salty oceans.Some colonies are at the surface of seawater, others in deep water.There are three groups of life in seawater: those that swim upstream include fish, cuttlefish, and whales; the second group consists of all the plants and animals that live on the bottom of the sea, where one can find such things as kelp, crabs, and starfish. organisms; the third group is plankton, which are the most important.Plankton are so small that they can only be seen under a microscope.Many marine organisms rely on plankton to survive.

Another type of community is a river community.Rivers provide habitat for many types of life.Plants, insects, fish live in the water, some on the surface and some by the river.

A wild community may be near a river, or it may be a field that has never been disturbed by humans, away from a natural lake or river.In this biome, one can find hares, chipmunks, and prairie dogs.Prairie dogs live in groups in underground homes that resemble houses with many rooms.

A desert is truly a community of many different plants and animals living together.Cacti, mesquite, sagebrush and wildflowers are a few plants that live in desert communities.In desert communities we can find many mammals such as jackrabbits, wood rats, woodchucks, mule deer, camels.Because these desert regions are so hot and dry, the animals that live there get most of the moisture they need from their own food.

Forest is a very special community.The plants and animals here live on three planes.Branches are the highest level, plants are the middle level, and ferns and berries are the lowest level.Among the forest dwellers you can find squirrels, chipmunks, porcupines, raccoons and opossums.You may also spot grouse, deer, foxes and bears.Many species of birds, insects and flowers live in forests.

Exercise
1.Which six natural communities are mentioned in the text?
2.Match the following words.

a.crab
b.rabbit

c.Ferns
d.starfish

A．forest community

B．wild community

C．seawater community

1. salt-water community, river community, field community,

desert community, forest community, human community.

2. a→C b→B c→A d→C
03 Mice Prefer Treats They Worked Harder to Get
Maybe your dad said: “The harder you work for something, the more you'll appreciate it.” Well, father really did know best. Because a new study finds that the harder mice have to work for a treat, the better it tastes .
Mice were trained to push levers to get either of two rewards. Press one lever, out comes a drop of sugar water. Press the other and they get a drop of different tasting sugar water.
Then things got interesting. For one of the treats, scientists gradually increased the amount of effort required for the payoff—from one lever-press to five, then 10, then 15. So by the end of the session, one type of sugar water cost 15 times more effort than the other.
The mice then retired to their home cage where both treats were freely available. And they showed a strong preference for whichever reward they'd worked harder to obtain. Based on how fast the mice sipped, they appeared to find the costlier sugar water more tasty .
Which makes evolutionary sense. An animal wouldn't survive if a little hard work left a bitter taste in its mouth.
Vocabulary
appreciate [? "pri:? ieit] vt. Appreciation, identification, comprehension;

vi. to increase in value
mice [mais] n. mouse (plural of mouse)
levers ["lev? z] n. leverage, means (plural of lever);

v. Pry with a lever (third-person singular of lever)
retired [ri"tai?d] adj. retired, claustrophobic;

v. Retirement (past participle of retire)
evolutionary["i:v?"lu:? ? n? ri] adj. evolved, developed, progressive

Practice
Talk about your view on this experiment.
Translation
Your dad probably said, "The harder you work on something, the more you appreciate it." Well, your dad does know a lot.Because a new study finds that the harder a rat tries to get a certain food, the better it tastes.

The researchers trained rats to push levers, which gave them one of two rewards -- pushing the first lever, and a drop of sugar water oozed out; pushing the second lever, and they got another drop of a different Taste of sugar water.

Then things start to get interesting.Scientists gradually increased the difficulty of obtaining one of the sugar waters, from pushing the lever once at the beginning, to pushing it five times, ten times... and finally pushing it fifteen times.Therefore, at the end of the experiment, it took fifteen times as much energy to obtain this sugar water as to obtain the other.

The mice were then returned to their cages, at which point both types of sugar water were provided free of charge.The mice showed a strong preference for the more difficult-to-obtain sugar water.Judging from the rate at which they drank the water, it appeared that the mice thought the more expensive sugar water tasted better.

This result has certain evolutionary implications.If redoubled efforts only resulted in a mouthful of bitterness, the animal would not try to survive.

Exercise
Tell us what you think about this experiment.

04 Pigeons Gamble on Unlikely Jackpot
Blackjack, slot machines, Texas hold'em. People love to gamble. And we're not the only ones. Study shows that pigeons will also pass up a sure thing in the hopes of a big payoff.
Theories about foraging say that animals should stick with the proverbial bird in the hand, especially when it comes to food. Eating is key to survival, so clever critters shouldn't take unnecessary chances. But these new findings suggest that pigeons don't always play it safe.
(End of this chapter)