1. When observing the slide specimen with a microscope, Xiao Ming used 10× eyepiece and 20× objective lens, while Xiao Qiang used.
10x eyepiece and 45x objective. What Xiao Qiang saw was different from that of Xiao Ming ()
A. the brightness of the visual field is obviously increased. B. the number of cells observed decreased.
C. the seen cell image becomes smaller. D. the field of vision is obviously expanded.
2. Divide the seeds with complete and full grains into group A and group B, and sow at 25℃ respectively. Group A was planted in fertile and moist soil, while Group B was planted in barren and moist soil. The germination status of these two groups of seeds is ().
A.b.a. germinates first. C. at the same time D. no germination.
3. On the same plant, pick three leaves from the same place in the morning, evening and late at night, use a punching machine to take the same size discs, decolorize them and treat them with iodine. The result is ().
A. The leaves picked in the morning are darker in blue. B. The leaves picked at night are darker in blue.
C. Leaves picked in the middle of the night are darker in blue. These three leaves are all blue.
4. Determine the contents of three substances in blood flowing in arteries and veins of an organ at a certain moment, and their relative values are shown in the right picture.
This organ is ()
A. Lung B. Brain C. Small intestine D. Muscle
5. The following is the combination of blood oxygen and hemoglobin in several tissues: the combination rate of tissue A is 45%, that of tissue B is 60%, that of tissue C is 75%, and that of tissue D is 85%, among which the most vigorous metabolism is ().
A. organization a, b, b, c, d and d.
6. There are three kinds of digestive juices: A, B and C, not gastric juice and pancreatic juice. Digestive juice A can promote digestive juice C to digest fat, while digestive juice A and digestive juice B can not digest protein, while digestive juice B and digestive juice C can digest starch. Therefore, the three digestive juices of A.B.C are () respectively.
A. Intestinal fluid, bile and saliva B. Saliva, intestinal fluid and bile
C. bile, saliva and intestinal juice
7. Use a special jar when making kimchi, and the jar mouth must be sealed with water. The purpose of sealing the jar mouth is ()
A. isolate the air and inhibit bacterial reproduction. B. Prevent dust and bacteria from entering the altar and prevent pollution.
C, creating an anoxic environment, which is beneficial to lactic acid fermentation; D, prevent gas exchange, which is beneficial to the breathing of acetic acid bacteria.
8. Blood types A, B, C and D are different. If B-type serum is used for examination, A and B's blood can agglutinate. After cross-matching test, A can only accept C's blood. Based on this, it is inferred that the blood type of these four people is ()
Answer, answer, answer, answer, answer, answer, answer, answer.
C.a，AB，o，b.d.ab，a，o，b。
9. 1989, Chinese scientists successfully introduced human growth hormone gene into carp eggs, and the growth rate of carp developed from this kind of fish eggs was obviously accelerated. The above facts show that ()
A there are obvious differences between dominant genes and recessive genes in cells. B. Genes in cells exist in pairs.
C. genes exist on chromosomes of biological cells. Biological characteristics are controlled by genes.
10. In an emergency, the lizard's tail can be broken automatically, and the broken part can also be flexed and stretched. This behavior of lizards is animal's ()
A. Aggressive behavior B. Defensive behavior C. Rhythmic behavior D. Group behavior
1 1. Biologists call for the protection of biodiversity, but experiments have proved that many wild animals carry disease-causing organisms. Do you think it should be ()?
A. kill organisms with bacteria. B. kill them all resolutely and completely, and isolate them all.
C. give antibiotics to the animal kingdom. D. resolutely protect them from close contact.
12. The following statement about biological evolution and ecology is incorrect ().
A. environmental factors that affect biological life are called ecological factors.
Weeds in rice fields will compete with rice for sunlight, nutrients and water.
C. Fertilization of crops and vegetables should be mainly based on quick-acting chemical fertilizers, with farmyard manure.
D natural selection is the reason for the development of organisms from simple to complex, from aquatic to terrestrial, and from low to advanced.
13. Tomato seedlings with basically the same growth were cultured in four pots of A.B.C.D, and other conditions were the same except for different fertilization conditions. After a period of time, which pot is the best for tomatoes to bear fruit ()
A. Pots with phosphorus fertilizer B. Pots with nitrogen fertilizer C. Pots with potassium fertilizer D. Pots without chemical fertilizer.
14. Which of the following is a feature of pseudomyopia ()
A. The anterior and posterior diameter of eyeball is shortened and imaged behind retina.
B. the curvature of the lens is too small and the refractive power is too weak.
C. The anterior and posterior diameter of eyeball is too long, and the object image falls in front of retina.
D. the adjustment structure of the eyeball is too tight and the refractive power is too strong.
15. Children were injected with sugar pills of polio vaccine, and the vaccinated vaccine and immunity were () respectively.
A. antigen, specific immunity B. antibody, specific immunity
C. antigen, nonspecific immunity D. antibody, nonspecific immunity
16. Carassius auratus keeps swallowing water in the water, and its main function is ()
A. filtering food B. adjusting density C. balancing body D. agreeing with 0| comment 2009-5-23 14: 18 № soul | level 1.
In the process of learning, put the textbooks, homework and materials of each subject together regularly. When you use it, you can know where it is at a glance. When some students looked for a book, they turned and disappeared. Time passes in the busy and anxious search. In my opinion, students who are disorganized can't learn well.
Comments: The improvement of learning efficiency is largely determined by other factors besides learning, because many factors such as people's physique, mood and state are closely related to learning efficiency.
abstract
Learning must pay attention to methods, and the essential purpose of improving learning methods is to improve learning efficiency.
The level of learning efficiency is the embodiment of a student's comprehensive learning ability. When I was a student, the level of learning efficiency mainly affected my academic performance. When a person enters the society, he will constantly learn new knowledge and skills at work. At this time, a person's learning efficiency will affect his/her work performance, and then affect his/her career and future. It can be seen that developing good study habits and high learning efficiency in middle school is of great benefit to people's life development.
It can be considered that people with high learning efficiency must be students with good academic performance (implication, good academic performance is not necessarily efficient). Therefore, for most students, improving learning efficiency is a direct way to improve their academic performance.
Improving learning efficiency is not a one-off event, and it needs long-term exploration and accumulation. The experience of predecessors can be used for reference, but we must fully combine our own characteristics. The factors that affect learning efficiency are internal factors, but more are external factors. First of all, we should develop good study habits and make rational use of time. In addition, we should also pay attention to the cultivation of basic qualities such as "concentration, intention and perseverance" and have a deep understanding of our own strengths and weaknesses. In short, "nothing is difficult in the world, I'm afraid there is a will."
Please also pay attention to your biological clock:
Everyone's situation is different, there are some differences. To find out the best study time, the human brain has certain activity rules in a day: generally speaking, at 8 am, the brain has rigorous and meticulous thinking ability; Thinking ability is the most agile at 3 pm; Memory is strongest at 8 pm; The reasoning ability gradually weakens during the day 12 hours. According to these laws, people's imagination is rich when they get up in the morning, so we should seize the time to catch some inspiration, do some conceptual work, read Chinese, recite English words, and take part in some physical exercises because of the fresh air in the morning. Do some rigorous work in the morning, listen carefully in class and take notes in class; In the afternoon, in addition to listening after class, you should also do the written homework of the day quickly and accurately; Strengthen memory and understanding in the evening and preview the next day's class. Arrange some effortless routine work at noon and evening, such as reading newspapers, collecting writing materials, taking a walk and having a rest.
Finally, I wish you good health, academic progress, all the best and success in the exam!
Occasionally ~
First, multiple choice questions
1. Cactus growing in arid areas has needle-like leaves, which is good for it ()
A. photosynthesis; B. reduce transpiration and maintain water in the body.
C. Breathe, decompose substances in the body D. Absorb and transport water.
2. The newly harvested rice must be dried as soon as possible ()
A. Enhance breathing B. Suppress breathing
C. promoting seed dormancy
3. Transplanted crops need soil for ()
A. Ensure that the roots constantly absorb organic matter from the soil. B. Reduce the loss of water in plants.
C. protect young roots and slender root hairs D. promote the normal respiration of roots.
Research shows that the content of carbon dioxide in the atmosphere is increasing gradually. Which of the following measures can alleviate this phenomenon ()
A. accelerate the development of industrial production
C. Cutting down trees D. Vigorously developing animal husbandry production
5. The water absorbed by watermelon plants is mainly used for ()
A. photosynthesis B. watermelon fruit expansion C. melon vine growth D. transpiration
6. There are many kinds of seeds in watermelon, because there is () in every flower of watermelon.
A. multi-ovary, multi-stamen, multi-ovule and multi-pistil
7. The main purpose of fertilization is to provide () for the growth of crops.
A. moisture B. inorganic salt C. energy D. organic matter
What part is the pistil of peach blossom made up of ()
A. Filaments, styles and ovaries
C. anther, filament and style filament, ovary and ovule
9. In the experiment of green leaves making organic matter under light, the purpose of putting potted geranium in the dark for one day and one night is ()
A. Depleting starch in leaves B. Producing a lot of carbon dioxide C. Absorbing carbon dioxide D in containers.
Absorb all the oxygen in the container
10. In the process of crop cultivation, () inorganic salts are most needed.
A. contains iron, zinc and calcium B. contains manganese, molybdenum and copper C. contains nitrogen, phosphorus and calcium D. contains nitrogen, phosphorus and potassium.
1 1. The main reason why plants grow up from childhood is ()
A. cell growth, cell differentiation B. cell differentiation, vacuole enlargement C. cell division, cell growth D. cell division, vacuole enlargement
13. Arbor Day stipulated in China is annual ().
A.b. March C. The first week of April D. The first week of March
14. The following substances do not enter plants through stomata ().
A. water vapor B. oxygen C. carbon dioxide D. inorganic salts
15. Plants are planted in the daytime ()
A. photosynthesis B. respiration C. transpiration D. all three actions have been carried out
16. The stem of woody plants can be continuously thickened because ().
A. bark xylem cambium phloem
17. Humans and apes have the same ancestor ().
A. chimpanzees B. macaques C. forest apes D. baboons
18. Sperm and egg cells meet and combine to form a fertilized egg ().
A. fallopian tube B. uterus C. ovary D. * * * *
19. The nutrients needed for embryo development in the maternal uterus come from ().
A. uterus B. maternal blood C. placenta D. umbilical cord
20. In the following groups of substances, which are both human components and human energy-supplying substances, is ().
A. starch, sugar, vitamin B. protein, fat and inorganic salts C. sugar, fat, protein D. protein, water and inorganic salts.
2 1. The digestive juice that can digest sugar, protein and fat is ().
A. bile b gastric juice c intestinal juice d saliva
22. The following description of alveolar characteristics is incorrect ().
The alveolar wall is a flat layer of epithelial cells.
B. The bread outside alveoli is surrounded by abundant capillaries.
C. There are many alveoli, and the contact area with gas is large.
D. There are smooth muscles in the alveolar wall, so the alveoli can expand and contract.
23. The structure of people eating food and breathing air is ().
A. Oral cavity B. pharynx C. larynx D. trachea
24. Which of the following statements may lead to food safety accidents ()
A. Fresh fruits should be washed with clear water or peeled before eating.
B. packaged food can't be eaten after its shelf life.
C. kitchens and cookers are always kept clean.
D. Wild mushrooms can be eaten.
25. The characteristics of adolescent psychological changes are ()
A: The inner world is very simple. What's the matter? Tell your parents.
B. Have a strong sense of independence, but are eager to get the care of parents and teachers when encountering setbacks.
C. Strong dependence, problems encountered in study and life are always solved by teachers and parents.
D. psychologically mature and sophisticated.
Second, short answer questions
1. In order to study the relationship between light intensity and photosynthesis intensity. In the evening, we put Ceratophyllum in a test tube filled with water, and then put the test tube at different distances from the incandescent lamp to observe the number of bubbles produced in the test tube. The data collected are as follows. Please answer the questions after the table according to the data and knowledge in the table:
Distance between test tube and lamp (cm)
10
20
30
40
Number of bubbles generated (pieces/minute)
60
25
10
five
(1) The relationship between the distance between the plant and the light source and the number of bubbles generated is _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _.
_______________________________________________。
(2) The generated bubble composition should be _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _.
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _.
(3) If the test tube is placed in a dark environment, your prediction result should be _ _ _ _ _ _ _ _ _ _ _.
____________________________________________________。
(4) From the above experimental data, it can be concluded that: _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
____________________________________________________。
Final review of biology in the first volume of the eighth grade
1. At present, there are about1.50,000 known species of animals. These animals can be divided into two categories: one is vertebrates, which have thorns in their bodies; The other is invertebrate, which has no spine in its body.
2. Biodiversity: 1, species diversity; 2. Diversity of living environment; 3, 00 the diversity of sports modes.
3. The reason why fish can survive in water is that two characteristics are very important: (1) it can get food by swimming and defend against enemies; (2) can breathe in water.
4. The structure that fish can overcome resistance in water: streamlined (spindle-shaped) body; The body surface secretes mucus.
When a fish swims, it relies on the left and right swinging of its tail on its trunk to generate the power to move forward. It relies on dorsal fin, pectoral fin, ventral fin and gluteal fin to keep balance, and caudal fin to keep the direction of progress.
6. When it is difficult to do experiments directly with the research object, sometimes experiments are done with the model, that is, imitating the experimental object to do the model, or imitating some conditions of the experiment. Such an experiment is called a simulation experiment.
7. Various fins play an auxiliary and coordinating role in sports.
8. Gills are the respiratory organs of fish.
9. There are abundant capillaries on the gills, so the gills are bright red.
10, gill filaments are many and thin, which is beneficial to full gas exchange in order to expand the contact area with water. Gills do not easily absorb oxygen in the air. After the fish left the water, the gill filaments covered each other, which reduced the contact area with the air and could not get enough oxygen from the air, so they died of lack of oxygen.
1 1, fish gills are very important for breathing in water: gills are bright red and contain rich capillaries; Branchial filaments are many and thin.
12. Water flows in from the fish mouth and out from the rear edge of gill cover.
13. In the water flowing from fish gills, oxygen decreases and carbon dioxide increases.
14, O2-in gas exchange water-in the capillary of gill filament.
Carbon dioxide in gill filament water
15, the main characteristics of fish: there are often scales on the body surface, breathing through gills, swimming through the swing of tail and the coordination of fins.
16, mouth without anus, food enters the digestive cavity through the mouth, and the digested food residue is still excreted through the mouth. These animals are called coelenterates.
17. Animals with soft bodies and shells are called mollusks.
18. Animals with hard armor are called crustaceans. Crustaceans breathe through gills.
19, coelenterates, mollusks and crustaceans are invertebrates.
20. All kinds of creatures 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 influenced by aquatic environment. The change of their species and the increase or decrease of their quantity will affect human life.
2 1. Compared with the water environment, the land environment is much more complicated. (1) is relatively dry; (2) The temperature difference between day and night is large; (3) Insufficient buoyancy in water; (4) gaseous oxygen; (5) The land environment is complex and changeable.
22. Adaptation of animals living on land to environment: 1. Generally, there is a structure to prevent water loss; 2. Not affected by the buoyancy of water, there are generally organs that support the body and exercise. Used for crawling, walking, jumping, running, crawling and other sports modes to eat and avoid the enemy; 2. Generally, various respiratory organs are located inside the body and can breathe air, such as trachea and lungs; 4. Generally, there are developed sensory organs and nervous system, which can respond to the changing environment in time.
Annelids are not mollusks, annelids are invertebrates.
24. Animals whose bodies are composed of many similar annular segments are called annelids.
25. Earthworms live in humid soil rich in humus, because they are cold-blooded animals with little temperature change and are suitable for earthworms to live.
26, body segmentation can make the earthworm's body movement flexible.
27. Earthworms rely on muscle contraction and relaxation, bristle support and fixed movement.
28. Earthworms have no special respiratory system. Earthworms' breathing depends on the body wall that can secrete mucus and keep it moist all the time. The earthworm's body wall is densely covered with capillaries, and the oxygen in the air first dissolves in the mucus on the body surface, then penetrates into the body wall and then enters the capillaries on the body wall. Carbon dioxide in the body is also discharged from the body surface through capillaries in the body wall.
29. Earthworms can't keep a constant body temperature and can only live in deep soil with little temperature change.
30. Compared with warm-blooded animals, warm-blooded animals are more adaptable to the environment and are conducive to normal metabolism.
3 1, the rabbit's body temperature is constant, not only by the hair on the body surface, but also by the developed nervous system, circulatory system and respiratory system.
32. Rabbits have long hind limbs, short forelimbs and muscular hind limbs, which are suitable for jumping.
33, front teeth-cut off the canine teeth of food-tear the molars of food-grind food.
34. The structure and position of rabbit's heart and lungs are similar to that of human body, which shows that human and rabbit are very close in classification and belong to mammals.
35. Eat plants (such as rabbits)
Carnivorous (as a wolf)
Omnivorous (as humans)
36. The cecum is mainly used to digest fiber, and the cecum of herbivores is developed.
37. Rabbit's teeth are divided into incisors and molars. Incisors are suitable for cutting plant fibers, and molars are suitable for grinding food. Rabbits have developed cecum in their digestive tract, which is in line with their habit of eating plants.
38. Rabbits have developed brains, nerves all over the body and developed limbs. They can sensitively perceive changes in the external environment and react quickly.
39. Mammals are the tallest animals, especially vertebrates. There are many kinds, about 4000 on the earth. Except for a few species, they all have the characteristics of body surface coat, viviparous and lactation. Other features: four cavities in the heart, breathing with lungs, constant body temperature, belonging to warm-blooded animals, with incisors, canines and molars.
There are more than 9000 kinds of birds in the world.
4 1, the shape of the bird is streamlined, which reduces the air resistance during flight.
42. Birds' feathers are divided into normal feathers and down feathers (with warm-keeping function). Normal feathers have quills and fan-shaped wings, which can increase the contact area with air and facilitate flight by flapping the air.
43. Birds' pectoral muscles are developed and attached to the keel process, which is conducive to flying in the air.
44. This bird's skeleton is hollow, light and strong, with a prominent sternum and a keel structure, which is convenient for developed pectoral muscles to attach to the sternum (keel), reducing weight and facilitating flight.
45. Digestive characteristics of birds: 1, large appetite and strong digestive ability, which can meet the digestion of energy during flight; 2. Feces are not stored, which reduces the weight and is beneficial to flying; 3. Short rectum and frequent defecation.
46. Birds have developed hearts and strong working ability, and their blood has strong ability to transport oxygen, which is conducive to flight.
47. Birds have developed airbags (not respiratory organs) to assist lung breathing and meet the demand for oxygen during flight.
48. The whole body of a bird is designed for flight.
49. Mammals in warm-blooded animals
bird
50. Birds are covered with feathers, and their forelimbs become wings, so they have the ability to fly quickly. There is an air bag in the body to assist lung breathing, and the body temperature is high and constant.
5 1. Insects are the most diverse animals, with more than 1 10,000 known species (accounting for 4/5 of the animal species). Insects have three pairs of feet and can crawl. Some insects' feet are specialized into jumping feet, which can jump; Most insects have wings and can fly. Insects are the only flying animals among invertebrates.
The wings of insects are different from those of birds in structure, but as far as flying is concerned, they all have these similarities: they are all fan-shaped structures conducive to flying. The operation of these structures is caused by the contraction and relaxation of muscles, which can produce upward lift and forward power in the air. Compared with their bodies, they are light and big, which is conducive to flying in the air.
53. The significance of wings to the life and distribution of insects: it is beneficial to feed, avoid enemies, expand activities and distribution, and find places suitable for mating and spawning.
54. External characteristics of insects: the body of insects is divided into three parts: head, chest and abdomen, and the moving organs-wings and feet are born in the chest. There are well-developed muscles in the chest, which are attached to the exoskeleton, which is a tough shell covering the surface of insects (molting will occur), protecting and supporting the soft organs inside and preventing water evaporation in the body.
55. Insects are classified as arthropods. Besides insects, arthropods include spiders, centipedes, shrimps, crabs and so on. Their similarities are: their bodies are composed of many segments; There is an exoskeleton on the body surface; The foot and antenna are segmented.
56. Larvae live in water, breathe through gills, undergo metamorphosis, then live an amphibious life, breathe through lungs and breathe through skin. This animal is called amphibian.
57. The behavior of animals depends on a certain body structure.
58. The exercise system of mammals consists of bones and muscles (bones, skeletal muscles (exercise muscles) and interosseous joints).
59. The exercise system consists of bones, skeletal muscles and skeletal connections (such as joints).
60, people have 206 bones skull, sternum, ribs (can't move).
Trunk bone (semi-active)
Movable joints (joints) of limbs.
6 1, people have 26 vertebrae (semi-mobile bone connection)
62. Joint structure: joint head, joint capsule, joint cavity (with synovial fluid to make joint activities flexible), joint fossa, and joint cartilage (cushioning effect).
joint capsule
Articular head
articular cavity
cartilago articularis
sucking disc
63. Joints act as fulcrums in motion and are the points around which bones rotate.
64. The main joints of human body: upper limb shoulder joint and lower limb hip joint.
Elbow and knee joint
Wrist and ankle joints
Finger joints and toe joints
65. All vertebrates have joints.
66. When exercising, the elbow joint, hip joint, knee joint and ankle joint are easily injured.
67. How to protect joints during exercise: First, make full preparations for exercise before exercise; Second, the intensity of exercise should be appropriate; Third, wear wrist pads and knee pads.
68. The thicker part of skeletal muscle (organ) is called muscle abdomen, and the thinner milky white part at both ends is called tendon.
69. Skeletal muscle has the characteristic of stimulated contraction.
70. Why does skeletal muscle affect bones: When skeletal muscle is stimulated and contracted by nerves, it will affect the movement of bones around joints, so the body will exercise.
7 1, the muscles connected with bones are always coordinated by two groups of muscles.
72. There are more than 600 skeletal muscles in the whole body. When the arm droops naturally, both biceps brachii and triceps brachii relax.
73, elbow flexion, biceps contraction, triceps relaxation; When the elbow is extended, triceps brachii contracts and biceps brachii relaxes.
74. Of course, exercise is not completed only by the exercise system, it needs the control and adjustment of the nervous system and the supply of energy, so it also needs the cooperation of the digestive system, respiratory system and circulatory system.
75. Summarize the role of bones, joints and muscles in exercise in one sentence: skeletal muscle contraction affects the movement of bones around joints, so the body moves.
76. Animals have various behaviors. From the way of acquiring behavior, animal behavior can be roughly divided into two categories. One is the innate behavior of animals, which is determined by the genetic material in animals, which is called congenital behavior; The other is the behavior obtained from life experience and learning through the role of environmental factors on the basis of genetic factors, which is called learning behavior.
77. Many behaviors are the result of the combination of innate behavior and learning behavior, such as bird migration.
78. Innate behavior is the most basic condition for animal survival. Learning behavior enables animals to adapt to the changing environment and survive better.
79. The higher an animal is, the stronger its learning ability and the more it can adapt to the complex environment. Similarly, the more complex the environment, the more behaviors you need to learn.
80. Congenital behavior has great limitations. If a creature has only innate behavior but no learning behavior, then it will be eliminated naturally.
8 1, for a person, skill training and knowledge learning are adapted to the development stage of the brain, and it is difficult to make up once the critical period of learning is missed.
82. Social behavior characteristics: 1. Some organizations often form within groups; 2. Clear division of labor among members; 3. Grades have also been formed in some groups.
83. Groups are arranged in a hierarchical system according to their size, strength, health and ferocity.
84. The "leader" enjoys food and spouse first, and chooses the nesting site first. Other members will obey it, dare not fight back against its attacks, and be responsible for directing the actions of the whole community.
85. Animals' movements, sounds and smells can all play the role of transmitting information.
86. The significance of social behavior to animal survival: It is often easier to get food and overcome the invasion of natural enemies by relying on the strength of groups, which can effectively ensure the reproduction of species, make groups better adapt to the environment and maintain the lives of individuals and races.
87. In nature, information exchange between living things is ubiquitous (people talk, animals talk). It is precisely because of the existence of material flow, energy flow and information flow that the relationship between organisms is complicated, and "one hair pulls one hair and moves the whole body", and organisms and the environment become a unified whole.
88. There are interdependent and mutually restrictive relationships between the food chain and various organisms in the food web. In an ecosystem, the number and proportion of various organisms are always maintained in a relatively stable state, which is called ecological balance.
The role of animals in nature: 1. Animals play an important role in maintaining ecological balance; 2. Animals can promote the material circulation of the ecosystem; 3. Help plants pollinate and spread seeds; 4. Biological control.
90. Biological control refers to the use of organisms to control pests and diseases. In addition to insect control, there are birds and bacteria.
9 1, the role of animals in people's lives: rich in nutrition and available for people to eat; Play a role in medical care; In appreciation and entertainment, literature and art have a certain image; People use it to describe some images or certain characteristics in life; Animals spread some diseases (injuries) to humans.
92. In the ecosystem, the number and proportion of all kinds of organisms are always kept in a relatively stable state.
Now scientists are studying the use of living things (such as animals) as "production workshops" to produce certain substances needed by human beings. This is a bioreactor.
94. Advantages of bioreactor: It can save the cost of building a factory building and purchasing instruments and equipment, and reduce complicated production procedures and environmental pollution.
95. Scientists invent and create various instruments and equipment by carefully observing and studying living things and imitating some structures and functions of living things. This is bionic.
96. A colony is an aggregate of bacteria or fungi that can be seen by the naked eye after reproduction.
97. Bacterial colonies are relatively small, the surface is smooth and sticky, or the fungal colonies that are rough and dry are generally several times to dozens of times larger than bacterial colonies. The colonies formed by molds are often fluffy, flocculent or cobweb-like, and sometimes they can be red, brown, green and black.
98. Bacteria and fungi, as well as their different species, can be roughly distinguished from the morphology, size and color of colonies.
99. Colonies are often used as an important basis for strain identification.
100. General methods for culturing bacteria or fungi: ① Preparation of nutrient medium containing nutrients. ② The culture medium was sterilized at high temperature and cooled. ③ Put a small amount of bacteria or fungi on the culture medium (this process is called inoculation). ④ Petri dishes are cultured in a constant temperature incubator (or a warm place indoors).