"Who Choose Them" Biological Diversity PPT Courseware 3

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"Who Choose Them" Biological Diversity PPT Courseware 3

primitive earth

On the primitive earth about 4.6 billion years ago, the sky was scorching like fire, lightning struck and thunder boomed; lava rolled on the ground and volcanoes erupted. This natural phenomenon became the "birther" for the origin of life. The huge thermal energy caused various materials on the primitive earth to move and change violently, giving birth to vitality.

pristine ocean

Due to continuous heat dissipation, the scorching surface of the primitive earth gradually cooled down. The water that originally ran from the earth to the sky condensed into raindrops and fell to the ground again. This lasted for many billions of years, forming the primitive ocean. During the rainfall process, some of the hydrogen, carbon dioxide, ammonia and alkane, etc., were brought into the primitive ocean; when the rain washed the earth, many minerals and organic matter continued to collect with the water into the ocean. The vast primitive ocean, where all things meet, the weather is endless, and a large amount of organic matter is continuously produced, making the ocean the cradle of life.

Observe the foxes living in different environments in the picture. What are their different characteristics? Can we speculate on the differences in the environments in which these three species of foxes live?

Gray fox: body length 50-80 cm; weight about 2-3 kg; main activity range: forests and swamps. Good at climbing trees and jumping freely between branches.

Red fox: aliases include: fox, fox, red fox, southern fox, grass fox

Red fox is the most common fox, with a body length of about 80 centimeters and a weight of 4-6.5 kilograms. It has a slender body and tail glands that can emit a peculiar odor, which is called "fox smell". Red foxes are widely distributed in Eurasia and North America, and have also been introduced to Australia and other places. They live in forests, shrubs, grasslands, deserts, hills, mountains, tundra and other environments, and sometimes live in the suburbs of cities.

Arctic fox: body length 50~60 cm, tail length 20~25 cm, weight 2500~4000 grams. Obesity. The mouth is short, the ears are short and slightly rounded. Arctic foxes molt twice a year. In winter, Arctic foxes are covered in snow-white fur, but in summer the color of their fur is almost the same as that of frozen soil. They are the real masters of the Arctic ice sheets. Not only do they live here for generations, but they have almost no natural enemies except humans.

Choices change creatures:

From the appearance of simple life forms on the earth 3.8 billion years ago to the rich and colorful life world today, changes in the earth's environment are always the main reason. Humans also played an important role in changing the living environment of organisms and domesticating some animals.

Class summary

Nature (changes in the environment) changes and selects organisms, and organisms form a variety of morphological structures due to changes in their living environment.

Artificial selection changes biological characteristics

Natural selection and artificial selection change organisms and create biological diversity.

general trend

Based on the above analysis, what do you think is the overall development and change of animals?

What is the trend?

In terms of body structure, animals range from simple to ________;

In terms of living environment, animals range from aquatic to ________;

In terms of adaptability, animals range from lower to _______;

This process of development and change of animals is called animal evolution.

The main reason animals evolve is _______________.

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"Who Choose Them" Biodiversity PPT teaching courseware:

"Who Choose Them" PPT Teaching Courseware on Biological Diversity Part One: Introduction of New Lesson The dinosaur family that once dominated the earth has perished, but the little mantis of the same era still lives on the earth. What determines the fate of life on earth? ..

"Who Choose Them" Biological Diversity PPT Download:

"Who Choose Them" Biological Diversity PPT Download Part One: New Course Lecture: The Departure and Stay of Frogs What kind of environment might they live in? Just like a mother cat and a father cat give birth to kittens of different colors, the offspring of frogs also have different colors...

"Who Choose Them" Biological Diversity PPT:

"Who Choose Them" Biological Diversity PPT Part One: The Go and Stay of Frogs Observe two frogs, what kind of environment might they live in? Just like a mother cat and a father cat give birth to kittens of different colors, the offspring of frogs also have different colors...

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Update Time: 2024-09-17

This template belongs to science courseware Science Edition for Sixth Grade Science Volume 1 industry PPT template

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