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Read the text and do the assignments that follow it.

CORAL REEFS

Tropical seas are known for their variety of colour and fascinating marine life. Coral reefs have a unique place in this aquatic world and their surrounding environment. Though it looks like a plant, coral is actually a marine animal of the invertebrate species having no spinal columns, like jellyfish. Coral reefs are sensitive ecosystems. Reefs have formed over millions of years, and their scientific study teaches us many things about the complex changes that our environment has undergone through the ages.

The body of the coral consists of a polyp a hollow, cylindrical structure which attaches its lower end to a surface. The free end is a mouth which gathers food and acts as a "stinger" paralyzing prey. The continual growth of new buds, or developing polyps, cause the old ones to die. The skeletons remain, however, creating a colony of corals, later developing into a reef.

Reefs grow faster in clear water and in the warm temperatures of tropical oceans are generally found at depths less than 46 meters, where sunlight penetrates, a necessary condition for corals to thrive and grow. Waves also carry food, nutrients and oxygen to the reef. Shallow, warm, tropical waters with strong wave action are ideal conditions for these unique organisms to flourish.

Prove that coral is an animal.

Describe the structure of the body of the coral.

Say how corals multiply. Say what conditions are necessary for corals to flourish.

 


UNIT 3

Read the text and say if the sentences are true or false.

Carolus Linnaeus

The Swedish naturalist and physician Carolus Linnaeus is renowned for his contribution to natural history. He established the modern scientific method of naming plants and animals using two Latin words. Linnaeus then developed an extensive system of classification that divided plants and animals into the classes, orders, families, genera, and species that form the basis of modern taxonomy (the classification of nature). In 1788 the Linnaean Society was founded in London, England, in his honor. As proof of the importance of his work, the society still preserves his collections and manuscripts.

 

1. Carolus Linnaeus is an English naturalist.

2. He developed a special system of classification.

3. Carolus Linnaeus formed the basis of genetics.

4. He established the modern scientific method of naming plants and animals using two Latin words.

 

2. Read the text and answer the questions.

Simple Organisms

Simple Organisms are viruses and one-celled organisms, such as bacteria, blue-green algae, and protists. Viruses are on the borderline between living and nonliving things. They are not true cells but simply genetic material surrounded by a protein coat. Viruses do not show life activities unless they are inside a living cell. They use their host's DNA to reproduce. Viruses cause many plant and animal diseases; unless the organism can protect itself, the virus spreads to cause illness and even death.



1. What are simple organisms?

2. Are viruses living or non-living things?

3. What for do they use some other organism?

4. Can viruses spread very rapidly and cause diseases?


Date: 2016-01-03; view: 192


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