I. animals living in water

1. There are about 1.5 million known animal species, which can be divided into vertebrates and invertebrates according to whether they have backbones or not. According to the living environment, it can be divided into terrestrial animals, aquatic animals and air animals.

2, the most common aquatic animals are fish, in addition, there are ① coelenterates, such as anemones and corals; 2 mollusks, such as squid and octopus; (3) Crustaceans, such as shrimps and crabs; ④ Aquatic animals such as dolphins (mammals) and turtles (reptiles).

3. The two most important characteristics of fish adapting to life in water are: ① they can get food by swimming and defend themselves against enemies. (2) can breathe in water.

The four major fishes are herring, silver carp, grass carp and bighead carp.

5. Fish are lower vertebrates.

6. The fish is spindle-shaped, which reduces swimming resistance and is suitable for swimming. Fish is divided into three parts: head, trunk and tail.

8. When a fish swims, it mainly relies on the left and right swinging of its body, trunk and tail fin to hit the water flow to generate forward power, and other fins play an auxiliary role. When fish move, dorsal fin, pectoral fin and ventral fin all have the function of maintaining balance, and caudal fin has the function of determining the direction of fish movement.

9. The sensory organ of fish is the lateral line (feel the current and determine the direction).

10, fish gills are bright red because they are rich in capillaries; The gill filaments are many and thin, which greatly increase the contact area with water and promote the gas exchange between blood and the outside world.

12. Water flows into the gills from the fish mouth, and then flows out from the back edge of the gill cover (gill hole). When water flows through the gill filament, oxygen dissolved in the water enters the capillary of the gill filament, while carbon dioxide is discharged into the water from the gill filament. Therefore, compared with the water flowing in through the mouth, the water flowing out through the gills has a lower oxygen content and a higher carbon dioxide content.

13, the main characteristics of fish are: suitable for living in _ water _; The surface quilt _ scale _ breathes with _ gills _; Swim by swinging the tail and coordinating the fins.

14. Anemones, jellyfish, corals and other animals have simple structures. They have mouths, but no anus. Food enters the digestive cavity from the oral cavity, and the digested food residue is still discharged from the oral cavity. These animals are called coelenterates.

15. Molluscs, such as mussels and moths, which rely on shells to protect their bodies, are called mollusks. Squid and octopus have degenerated shells and are also mollusks.

16, shrimps and crabs have hard nails on their bodies, which are called crustaceans.

17. Various organisms in water are an important part of aquatic ecosystem. They form a close and complicated connection through food chain and food web, and at the same time they are all affected by water environment. The change of their species and the increase or decrease of their quantity will affect human life.

18. Seahorses are fish, whales, dolphins and seals are mammals, and turtles and turtles are reptiles.

Two. Earthworms, an animal that lives on land.

1, adaptation of terrestrial animals: ① dry climate ... structures to prevent water loss in the body, such as reptiles with horny scales or nails and insects with exoskeletons. ② Water lacks buoyancy ... organs that support the body and movement ... There are many kinds of movement modes, such as crawling, walking, jumping, running and crawling. In order to find food and avoid the enemy. (3) Gaseous oxygen for breathing ... There are respiratory organs that can breathe in the air and are located in the body, such as lungs and trachea (except earthworms, which breathe by the body wall). (4) The temperature difference between day and night is large, and the environment changes rapidly and complicatedly ... There are developed sensory organs and nervous system, which can cope with the changeable environment in time.

2. Earthworms live in moist soil rich in humus, make their bodies squirm through the cooperation of muscles and bristles, and breathe by the body wall that can secrete mucus and always keep moist. You can judge the beginning and end according to the fact that the infant is attached to the front end of the body (also called the reproductive belt).

3. The significance of earthworm segmentation: it can make the earthworm move flexibly and turn easily.

4. Touching the abdominal surface of earthworm segments with fingers has a rough feeling. Observing with a magnifying glass, we can see that there are many small protrusions on the abdominal surface that are bristles, and the role of bristles is to assist movement (fixation; Support)

5. The reason why earthworms dig holes in the deep layer of moist soil: It can provide earthworms with suitable living and living environment and breeding conditions, which generally include suitable temperature, humidity, gaseous oxygen, food and habitat that is easy to avoid enemies. Earthworms can't keep a constant body temperature and can only live in deep soil with little temperature change.

6. In the experiment of observing earthworms, why do you often wipe the body surface of earthworms with wet cotton balls soaked in water to keep the body surface moist? Earthworms don't have a respiratory system, but rely on a body wall that can secrete mucus and keep it moist all the time.

7. Earthworms' living environment: burrowing in soil with certain temperature and humidity, little change in temperature difference and rich humus. Living habits and eating habits: generally, I don't sleep at night and feed on dead leaves, rotten roots and other organic substances.

8. Earthworms will climb to the ground after heavy rain. Reason: After the heavy rain, too much rain will crowd out the air in the soil, so the burrowing earthworm is forced to climb to the surface to breathe.

9. Breathing process of earthworm: The body wall of earthworm is densely covered with capillaries, and the oxygen in the air first dissolves in the mucus on the body surface and then enters the capillaries on the body wall. Carbon dioxide in the body is also discharged from the body surface through capillaries on the body wall.

10. Animals whose bodies are composed of many similar annular segments are called annelids, such as earthworms, nereis and leeches.

Three. Animals that live on land-rabbits

1. Mammals: viviparous, breastfeeding (high survival rate of offspring), hairy body surface and constant body temperature, such as rabbits and giant pandas.

2. Warm-blooded animals: animals that can keep their body temperature constant through self-regulation so that their body temperature does not change with external changes, including birds and mammals. On the contrary, animals whose body temperature changes with the ambient temperature are temperature-changing animals, such as snakes and insects. The significance of constant temperature: reducing dependence on the external environment and expanding the scope of life and distribution.

3. Rabbit: Hair on the body surface (insulation), breathing with lungs, four cavities in the heart, systemic and pulmonary circulation, constant body temperature, developed incisors and molars, developed cecum (under the action of bacteria, it is helpful for the digestion of plant fibers), developed brain and flexible limbs.

4. Jumping is the main movement form of rabbits (the back is longer than the front legs and muscular).

5, the feeding habits of rabbits: plants (grass). Rabbit's body is divided into four parts: head, trunk, silk and tail.

6. Rabbit's teeth are divided into incisors and molars. The front teeth are like chisels, suitable for cutting food, and the molars have a wide chewing surface, suitable for grinding food. Rabbits have developed cecum, which is suitable for rabbits to eat plants. Mammals such as wolves and tigers also have sharp canine teeth, which are used to tear food (also used for attacking and preying).

6. Diaphragm is a unique structure of mammals.

7. Adequate food, water and shelter are the basic environmental conditions for the survival of terrestrial animals.

8. The internal structure of rabbits is similar to that of humans, indicating that humans and rabbits are close in taxonomic status and belong to mammals, but human cecum has degenerated because humans are omnivorous.

Fourth, flying animals-domestic pigeons

1. Animals flying in the air include insects, bats and birds.

There are more than 9000 kinds of birds in the world. Except for a few birds such as ostriches and penguins, most of them are good at flying. Flying expands the range of birds' activities, which is conducive to foraging and breeding offspring.

3. Birds are suitable for flying: ① the body is streamlined (which can reduce the air resistance during flight); ② The body surface is covered with feathers; Forelimbs become wings; ③ There are towering keel-like protrusions on the chest; Long bones are hollow (filled with air); ④ The pectoral muscles are developed; ⑤ Eat a lot and digest quickly. That is, the digestive system is developed, and the digestion, absorption and elimination of feces are very rapid. ⑥ The heart has four chambers, with fast heartbeat, perfect circulatory system structure and strong ability to transport nutrients and oxygen. ⑦ There are developed airbags, which can not only lose weight, but also form unique double breathing with the lungs. 8 short beak, toothless mouth, no bladder, short rectum, timely defecation, degeneration of right ovary and fallopian tube (these are all for weight loss and suitable for flying).

In a word, a bird is an animal with feathers on its surface, wings on its forelimbs, the ability to fly quickly, an air bag inside and a high and constant body temperature.

4. Wings are the flying organs of birds. Airbags help the lungs breathe.

5. Birds' feathers are divided into normal feathers (mainly used for flying) and fluff (mainly used for keeping warm).

6. Pigeons have no teeth in their mouths, and food enters crops through the pharynx and esophagus without chewing. -Into the muscular stomach (grinding food with sand and pebbles).

Five, flying animals-insects

1. Insects are the most diverse animals, exceeding 1 10,000 species. They are also the only flying invertebrates, so they are the most widely distributed animals.

2. The insect body is divided into three parts: head, chest and abdomen. There are usually three pairs of feet and two pairs of wings. Spiders, centipedes, shrimps and crabs are not insects, but they are all arthropods. Arthropods are characterized in that the body is composed of many segments, with exoskeleton, feet and tentacles on the surface.

3. The exoskeleton of insects is a tough shell covering the surface of insects, which can protect and support the soft organs inside and prevent the evaporation of water in the body.

2. Amphibians: larvae live in water, breathe through gills, develop into adults through metamorphosis, live in amphibians, breathe through lungs, and use skin to assist breathing. Representative animals: frogs and toads.

Six, the movement of animals

1. The motor system of mammals consists of bones and muscles. Bones are made up of many bones.

2. Skeletal muscle includes a thick abdomen in the middle and thin tendons at both ends (milky white). The two ends of a group of muscles are attached to different bones. Skeletal muscle has the characteristic of contraction after nerve stimulation.

3. Skeletal muscles can only contract and pull the bone, but can't push it away, so at least two groups of muscles are connected with the bone, and they cooperate with each other to complete various activities, especially elbow extension and elbow flexion: when elbow flexion, the biceps brachii contracts, the triceps brachii relaxes, and when elbow extension, the opposite is true.

4. Double ratio droops naturally, biceps brachii relaxes and triceps brachii relaxes; When lifting a heavy object vertically with both hands or grasping the horizontal bar with both hands, the body naturally sags, and the biceps brachii and triceps brachii contract.

5. Functions of sports system: sports, support and protection. In exercise, the nervous system plays a regulatory role, bones play a lever role, joints play a fulcrum role (also called fulcrum role), and skeletal muscles play a dynamic role. It can be seen that the human body must have the adjustment of the nervous system, the participation of bones, skeletal muscles and joints, and the coordination of multiple groups of muscles to complete an action.

6. Relationship between bones, joints and muscles: Skeletal muscle contracts, which affects the bones attached to it and moves around the joints, so the body moves.

7. The exercise system is controlled and regulated by the nervous system, and completes the exercise with the cooperation of the digestive system, respiratory system and circulatory system (energy comes from the decomposition of organic matter). Developed sports ability is conducive to predation and avoidance of the enemy, thus adapting to the complex and changeable environment.

8. The joint consists of articular surface, articular capsule and articular cavity. The articular surface includes articular head and articular fossa. The structural features that make the joint firm are: joint capsule and ligaments inside and outside the joint capsule. The structural feature that makes joint movement flexible is that the articular surface is covered with a layer of articular cartilage with smooth surface, and the inner surface of joint capsule can secrete synovial fluid, which can reduce the friction between the two articular surfaces during exercise and cushion the vibration during exercise.

9. Dislocation: The joint head slides out of the joint socket. (due to exercise or physical labor, due to overexertion or accidental fall. )

Six, animal behavior

1. According to different behaviors, animal behaviors can be divided into aggressive behaviors, feeding behaviors, defensive behaviors, reproductive behaviors and migratory behaviors. According to the different ways of acquisition, it can be divided into innate behavior and learning behavior.

2. Congenital behavior refers to the innate behavior of animals, which is determined by the genetic material in the body and is necessary to maintain the most basic survival, such as spiders weaving webs, bees collecting honey, ants nesting and so on. Learning behavior refers to the behavior obtained from life experience and learning through the role of environment on the basis of genetic factors. The higher an animal is, the stronger its learning ability, the stronger its ability to adapt to the environment, and the greater its significance for survival.

2. Social behavior: the behavior of animals living in groups, in which different members of the group work together to maintain the life of the group. (Note: Not all animals living in camps have social behavior, such as locusts. )

3. Most social behaviors have the following characteristics: ① there is a clear division of labor among the members of the organization within the group; ③ Some even form a hierarchy.

4. Communication: The phenomenon that an animal in a group sends some information to other individuals, and the individual who receives the information produces some behavioral response. Division of labor and cooperation need to exchange information at any time, including actions, sounds, smells and so on.

5. Using extracted or synthetic sex pheromones as attractants can trap and kill agricultural pests; Putting a certain amount of sex pheromones in farmland interferes with the communication between males and females, making males unable to judge the position of females and mate, and also achieving the purpose of controlling the number of pests.

Namely: (1) making insect sex pheromones to trap and kill insects; (2) creating interference, so that insects can't identify the sex pheromones of the same kind of insects.

6. Inquiry experiment: ask questions, make assumptions, make and implement plans, and draw conclusions (experimental phenomena). The above questions will be answered according to the following experiments. The textbook has 4 pages, 23 pages, 34 pages, 35 pages, 39 pages, 4 1 page.

Seven, the role of animals in the biosphere

1. The role of animals in nature: ① maintaining the ecological balance of nature; (2) promoting the material circulation of the ecosystem; ③ Help plants pollinate and spread seeds.

2. Ecological balance: The quantity and proportion of various organisms in the ecosystem have always remained relatively stable. This phenomenon is called ecological balance.

2. There are interdependent and restrictive relationships between the food chain and various organisms in the food web. If any one of them goes wrong, it will affect the whole ecosystem. It is precisely because of the existence of material flow, energy flow and information flow that all kinds of creatures and environments become a unified whole.

3. The role of animals in people's lives: they can be eaten, used medicinally and watched by human beings, which is closely related to bioreactor and bionics.

4. Bioreactor: Using biology as a "production workshop" to produce some substances needed by human beings. This organism or an organ of an organism is a bioreactor. At present, the most ideal bioreactor is "mammary gland bioreactor". Its significance lies in: low production cost, high efficiency, simple equipment, obvious product effect and reduced industries.

5. Pollution, etc.

6. Bionics: Inventing and creating various instruments and equipment by imitating some structures and functions of living things.

6. Common bionic examples: "anti-load suit" worn by astronauts, electroluminescence, radar, thin-shell buildings and intelligent robots.

Eight, experimental exploration

1, carefully observe the chest and abdomen of locusts. You can find a row of neatly arranged holes on the left and right sides. This is the valve. The valve is connected with the trachea in the locust body, and the valve is the gateway for gas to enter the locust body. Please refer to the given.

Experimental materials, design an experiment to prove that the valve is the gateway for locust gas to enter.

Question: Is the valve the gateway for locust gas to enter?

Suppose that the valve is the gateway for locust gas to enter.

Materials and utensils: (1) two live locusts; (2) two test tubes; (3) clear water; (4) glass strips; (5) thin lines.

Experimental steps: (1) Add equal mass of water into two test tubes, labeled as A and B respectively;

(2) fixing locusts on glass strips with thin wires;

(3) Immerse the head of one locust in the water of test tube A, and immerse the chest and abdomen of another locust in the water of test tube B ... and then observe it after a while.

The expected result of the experiment: the locust in the test tube is dead, and the locust in the test tube A is still alive.

Experimental conclusion: the valve is the gateway for locust gas to enter.

Discussion: Choose two grasshoppers with the same size and living conditions to reduce the interference of other factors on the inquiry.

2. Explore the foraging behavior of ants: Take a piece of cardboard, set four points A, B, C and D on it, put sugar, Chili sauce, sour vinegar and bread on it respectively, and then put it near the ant nest. Observe and answer the following questions:

(1) Question: Can ants identify and feed on food?

(2) Suppose that ants can recognize food and feed on it.

(3) In the experiment, the function of putting Chili sauce and vinegar is:? Contrast.

(4) expected phenomenon: ants have climbed on sugar and bread.

(5) It is concluded that ants can recognize and feed on food.

(6) How to deal with ants after the experiment: Put them back into nature.

3. Design inquiry experiment

Background knowledge: Earthworms live in moist, loose and organic-rich soil. Its body is composed of many knots, with a wet surface and many rough bristles. Earthworms rely on muscles and bristles to move.

Please design an experiment to explore: On what surface does earthworm climb fast?

(1) My question is: On what surface do earthworms climb fast?

My hypothesis is that earthworms climb fast on rough surfaces.

(3) Design of experimental scheme: Put individual robust live earthworm on rough paper and observe its movement; Put a stout live earthworm on the glass plate and observe its movement; Repeat the above experiment for 3-5 times.

(4) Prediction result: Earthworms climb very fast on rough surfaces.

The conclusion is that earthworms climb fast on rough surfaces.

4. Many insects have the habit of tending to light sources. Are insects phototactic? According to your own life experience, choose 3-5 kinds of insects, such as ants, crickets, mosquitoes, silkworm moths, cockroaches and so on. And design experiments to explore whether all insects have phototaxis.

Suppose that not all insects have phototaxis.

Ask a question: Do all insects have phototaxis?

Design experiment: ① Take 5 ants, 5 crickets, 5 mosquitoes, 5 silkworm moths and 5 cockroaches.

(2) Put these five kinds of insects in a dark room, and then use a small flashlight to send a bright and dark flash to this dark room. After a while, mosquitoes and silkworm moths found the flash and flew towards the light, but crickets, ants and cockroaches were not close to the light source.

③ Repeat the above experiment for 3 ~ 5 times.

Experimental phenomenon: mosquitoes and silkworm moths found the flash and flew towards the light, but crickets, ants and cockroaches didn't get close to the light source.

Experimental conclusion: Not all insects have phototaxis. Moths and mosquitoes generally have phototaxis.

A classmate wanted to explore the influence of soil moisture on earthworm life, but he didn't finish it. Please continue to do it.

(1) Do you think he can only find earthworms to do experiments in a humid, loose and humus-rich environment?

(2) According to the requirements of scientific experiments, he must design more convincing control experiments. In this experiment _ soil moisture (or moisture) is a variable, so it should be controlled well.

(3) Your hypothesis is that soil moisture has an effect on soil.

(4) Please design an experiment to explore the influence of soil moisture on earthworms: (just write down the specific operation steps) Prepare a box, spread a layer of dry soil on the bottom, pour a proper amount of water to half, then put 10 earthworms with similar shapes and sizes in the middle, cover the box and observe after a few minutes.

(5) Implementation plan

(6) Soil moisture has an influence on earthworm's life.

(7) Expression and communication

6. Pieris rapae is a small dark green carnivore that feeds on the leaves of cruciferous vegetables. It is the larva of Pieris rapae.

The flowers of Cruciferae plants are generally composed of four petals, which are arranged in a cross shape. Chinese cabbage, cabbage and rape are all cruciferous vegetables.

(1) Ask questions

Pieris rapae always feeds on cruciferous plants. Is this behavior innate?

(2) Suppose that Pieris rapae feeds on cruciferous plants, which is its innate feeding instinct, especially its innate behavior.

(3) Design and complete the experiment.

◆ Culturing Pieris rapae: look for the eggs of Pieris rapae and isolate the eggs after finding them.

◆ Juicing: Take leaves of cruciferous vegetables such as Chinese cabbage and cabbage to juice.

◆ Coat the filter paper with juice: coat the squeezed juice on the filter paper.

◆ Observation: Using filter paper without juice as control, observe the place where Pieris rapae tends to feed (4) Test the hypothesis and draw a conclusion.

The behavior of Pieris rapae feeding on cruciferous plants is innate.

(5) Discuss and improve the plan

◆ Purpose of egg isolation feeding: Only by egg isolation feeding can we explain whether some behaviors of Pieris rapae are instinctive or acquired, thus making the inquiry credible.

◆ Separation method of Pieris rapae eggs: It is not difficult to separate the eggs when raising Pieris rapae under artificial conditions. However, it is still difficult to raise and survive.

First of all, we should try our best to create feeding conditions close to the natural living environment for Pieris rapae, such as suitable light, temperature, humidity, sufficient fresh food and so on. Secondly, the number of aquaculture can not be too small, otherwise it is hard to say.

Ming problem.

◆ You can choose plant leaves containing special volatile oil, such as mint leaves and celery leaves. See if Pieris rapae likes it. It is best not to have hair or thorns on the leaves to avoid interference from other factors.

◆ The experimental blade should be the same size as the filter paper. The purpose of this is also to reduce the interference of other factors on the inquiry.

◆ The color of the filter paper should be the same as that of the vegetable leaves. The same color is also chosen to avoid interference from other factors.

◆ It is best to be hungry for a period of time in advance, and do this research when the cabbage butterfly has a big appetite. You can put the filter paper and the leaves on the same horizontal line, so that the distance between the cabbage caterpillar and the filter paper and the leaves is the same (not too far). Let go of the cabbage caterpillar and see what it will eat.

The control experiment should be carried out at the same time and place: only in this way can the exploration be rigorous and effective.

7. The animals in the group send some information to other individuals, and the individuals who receive the information have some behavioral reactions. This phenomenon is called communication.

(1) Ask a question: How do ants communicate information?

(2) Suppose that ants transmit information through their sense of smell.

(3) Design and complete the experiment.

When designing experiments, some foods far away from ant nests should include both meat and plant foods. Because there are many kinds of ants, their eating habits are different, some are carnivorous, some are phytophagous and some are omnivorous. When raising ants, we should also pay attention to their feeding habits. The suitable temperature for ants to grow and reproduce is 19 ~ 29℃, and they hibernate below 10℃. The air humidity in the cave is required to be 90% ~ 95%, and the water content of feeding sand is 10%- 15%.

(4) test the hypothesis and draw a conclusion

Support the hypothesis. One way for ants to communicate is through their sense of smell.

I. Bacteria and fungi

7. Colony: An aggregate visible to the naked eye formed by bacteria or fungi after reproduction, called colony.

Bacterial colony characteristics: the surface is small, smooth and sticky or rough and dry, white;

Fungal colony characteristics: large, fluffy, flocculent cobweb-like, with red, green, yellow, brown, black and other colors.

8. Culture methods of bacteria and fungi: ① preparation of culture medium ② high temperature sterilization ③ inoculation ④ constant temperature culture.

9. Culture medium: organic matter containing nutrients.

10. The survival of bacteria and fungi also needs certain conditions: moisture, suitable temperature, organic matter (nutrients), certain living space, etc. In addition, some are aerobic and some are anaerobic (that is, life activities are inhibited when aerobic). Except for a few bacteria, they can't synthesize organic matter by themselves, and can only use ready-made organic matter as nutrition (i.e. heterotrophic nutrition).

1 1. Scientists have discovered archaea in extremely special environments such as deep-sea craters. The existence of archaea shows that: ① archaea has strong adaptability to the environment; ② Bacteria are widely distributed.

12. In hot summer, food is perishable, and many people get gastroenteritis. The reason is that in hot summer, the air humidity is high and the temperature is high, which is suitable for the reproduction and growth of bacteria and fungi. If the food is not preserved properly or for a long time, it will deteriorate due to the pollution of bacteria and fungi, and people will get gastroenteritis if they eat the deteriorated food.

13. Clothes washed and dried will not mildew, but dirty clothes and shoes are prone to mildew. The reason is that the washed clothes are clean and dry, lack of nutrition, and are not suitable for the propagation of fungi, so the washed clothes are not easy to grow mildew; On the contrary, dirty clothes provide a suitable growth environment for fungi, so dirty clothes are moldy.

14. When making kimchi, cover it and seal it with water. The purpose is to prevent air from entering the tank, but to maintain the anoxic environment in the tank, because lactic acid bacteria can only decompose organic matter in vegetables into lactic acid in anoxic or anaerobic environment.

15.65438+Dutch Levin in the second half of the 7th century? Hook invented the microscope and discovered bacteria; /kloc-in the 0/9th century, Pasteur, the "father of microbiology", used the gooseneck experiment to prove that bacteria are not naturally produced, but are produced by existing bacteria.

16. Bacteria are very small.10 billion bacteria are only as big as a grain of rice and a single cell. (The virus is smaller than it)

17. bacterial characteristics: tiny, rod-shaped, spherical, spiral and other forms, without forming nuclei. Most of them can only live with ready-made organic matter and belong to decomposers. Split and reproduce. Some bacteria can form a dormant body with strong resistance to adverse environment, which is called spore.

18. structural characteristics of bacteria: the basic structure includes: cell wall, cell membrane, cytoplasm, DNA concentration area, no forming nucleus; No chloroplasts; Accessory structure: some bacteria have capsule (protective effect) outside the cell wall, and some bacteria have flagella (for swimming in water); Some bacteria form spores (light dormant bodies resistant to harsh environment) in the late stage of growth and development.

19. Master the bacterial structure diagram on 60 pages of the textbook.

20. The reproduction mode of bacteria: division and reproduction, fast, divided once in less than half an hour.

2 1. Nutritional mode of bacteria: general heterotrophy (including saprophy and parasitism), that is, there is no chloroplast, and most bacteria can only survive by using ready-made organic matter and decompose the organic matter into simple inorganic matter.

22. Bacteria are decomposers in the ecosystem.

23. What are the characteristics of bacteria related to their distribution? Bacteria are tiny and easy to be carried by various media; Split propagation, rapid propagation, large number; In the later stage of growth and development, some bacteria contract and their cell walls thicken to form spores, which have strong resistance to adverse environment; Spores are small and light, can be scattered around with the wind, and can germinate into bacteria when they fall in a suitable environment. These characteristics are beneficial to the wide distribution of bacteria.

24. Comparison of animal, plant and bacterial cells

Compare animal cells, plant cells and bacterial cells.

Cell wall ×√√

Cell membrane √√√

Cytoplasm √√√

There is a DNA concentration area in the unformed nucleus.

Chloroplast ×××××

Some pods have ××××

Flagella ×× Some have it.

25. Fungal characteristics: The thallus is composed of hyphae connected by many cells; Each cell has a cell wall, a cell membrane, a cytoplasm and a nucleus; There are also unicellular fungi, such as yeast; Without chloroplasts, they all live with ready-made organic matter, that is, heterotrophy; Reproduce offspring with spores

26. Penicillium: turquoise, with spore-bearing hyphae in a broom shape; Aspergillus: dark brown (sometimes yellow, green, etc. ), spores attached to the top of radial hyphae; Mushrooms get nutrients from decaying plants. These fungi live in places with suitable temperature, sufficient water and rich organic matter.

27. Various fungi: mushrooms, fungus, tremella, ganoderma lucidum.

28. Mushrooms are also assembled from mycelium.

Nutrition mode: heterotrophic (saprophytic)

Reproduction: Spore reproduction

Environment: dark and humid, rich in organic matter and warm.

29. Yeast (understanding)

⑴ shape: (single cell) oval, colorless.

⑵ Structure: cell membrane, cytoplasm, nucleus, cell wall, vacuole, no chloroplast.

⑶ Nutritional mode: heterotrophic (saprophytic) aerobic: glucose-carbon dioxide+water+energy (multiple)

Anaerobic: glucose-carbon dioxide+alcohol+energy (less)

(4) Propagation mode: bud propagation, spore propagation under special circumstances.

30. Mushrooms, fungus and other edible fungi are collectively referred to as edible fungi.

3 1. The role of bacteria and fungi in nature:

① Participate in the material cycle as a decomposer. That is, the remains of animals and plants are decomposed into carbon dioxide, water and inorganic salts, which are reabsorbed by plants and made into organic matter. Therefore, it plays an important role in the circulation of carbon dioxide and other substances in nature.

② Causes diseases of animals, plants and people. These microorganisms live parasitically and absorb nutrients from living animals and plants. Such as tonsillitis caused by streptococcus, tinea caused by fungi, wheat leaf rust and so on. Note: beriberi has nothing to do with fungi (it is caused by vitamin B 1 deficiency).

(3) with animals and plants. * * * refers to the phenomenon that one creature and another live together, interdependent and inseparable, in short, mutual benefit * * *. Such as fungi and algae grow together to form lichens.

Another example is rhizobia and leguminous plants. Rhizobia transform nitrogen in the air into nitrogen-containing substances that plants can absorb, thus increasing the content of nitrogen in soil, improving soil fertility and increasing crop yield (nitrogen is a substance that plants need in large quantities).

Function: Some bacteria in rabbits, cows and sheep help to decompose vitamins.

With people: some bacteria in the human intestine can produce vitamin B 12 and vitamin K, which is beneficial to the body.

32. The utilization of bacteria and fungi by human beings is reflected in four aspects:

(1) food production. That is, the application of fermentation principle. Fermentation is a process in which organic matter is decomposed into some products by yeast or other fungi at a certain temperature.

② Food preservation.

Causes of corruption-bacteria and fungi decompose organic matter in food and grow and reproduce in it;

Preservation principle-kill bacteria and fungi or inhibit their growth and reproduction;

Common saving methods:

Pasteur disinfection method (based on the principle of high temperature sterilization)

Tank storage method (based on the principle of high temperature disinfection and prevention of contact with bacteria and fungi)

Freezing method, cold storage method (based on the principle that low temperature can inhibit bacteria)

Vacuum packaging method (based on the principle of destroying the living environment of aerobic fungi)

Sun drying and smoking, salting, dehydration and osmotic preservation (based on the principle of removing water to prevent the growth of bacteria and fungi)

Use preservatives

Use rays

③ Disease prevention and treatment. Mainly refers to antibiotic therapy (such as penicillin) and transgenic technology to produce drugs (such as insulin). Antibiotics are substances produced by fungi (and actinomycetes), which can kill some pathogenic bacteria.