Biological life needs nutrition, and all kinds of nutrients needed by biological life in the biosphere ultimately come from photosynthesis of green plants, so the topic is right.
Plants absorb water, inorganic salts and carbon dioxide from the outside, and make their own nutrients such as starch through photosynthesis; Animals can't make organic matter by themselves. They feed on plants or other animals and get nutrition from them.
Biological and abiotic phases refer to organisms with kinetic energy, which can depend on and promote each other with the external environment. Metabolism and heredity are the most important and basic characteristics of living things. Metabolism shows that all living things must have anabolism and catabolism.
These two are completely opposite physiological reaction processes. Genetic materials can be copied and handed over to the next generation for reproduction through self-division or sexual reproduction to avoid extinction, which is the basis of life-like phenomena.
I. Biological characteristics
1, biological life needs nutrition. Living things need to get nutrients from the outside world all their lives to survive.
2. Living things can breathe. Most living things need to inhale oxygen and exhale carbon dioxide.
3. Bioenergy can excrete the wastes produced in the body.
4. Organisms can respond to external stimuli.
5. Organisms can grow and reproduce.
6. Organisms also have other characteristics. All living things are made up of cells except viruses.
Second, judge which of the following are creatures and which are not?
Robots, stalactites, corals, corals, sun, water, trees, people, animals.
Third, investigate the creatures around us.
(a), the general method of investigation:
1, and clarify the purpose of the investigation. 2. Choose materials and appliances. 3, method steps:
(1) Select the scope of investigation. (2) grouping. (3) Design the investigation route. (4) investigation records. (5) Classification analysis.
(2) Classification of organisms.
1, divided into plants, animals and other organisms according to morphological structure; 2. According to the living environment: terrestrial organisms and aquatic organisms; 3. According to use: crops, poultry, livestock and pets.