answers to after-class exercises in compulsory education textbooks
unit 1 biology and biosphere
chapter 1 understanding biology
section 1 characteristics of biology
1, (1)×(2)√(3)×(4)×
2, omitted
Coral is a creature, an animal in the ocean, with animal characteristics.
(2) The shallow water area can get more sunlight, and has a suitable temperature, which is beneficial to the growth of algae and can provide more oxygen for corals. Therefore, corals generally grow in warm shallow waters.
Investigating the living things in the surrounding environment
Reference answer: slightly
Chapter II Understanding the Biosphere
Section I Relationship between living things and the environment
1. (1)×(2)×(3)√(4)×
2. This poem describes the influence of temperature on plant growth. Because the temperature in the mountains is relatively low in the same season, the growth of peach trees is relatively slow. Peach blossoms growing in the plain area have withered in April, while peach blossoms in the mountains have just opened.
3, (1) farmer cattle/clover pollination
cats/voles/ground bees
(2) Answer: If there are fewer cats, voles will multiply in large numbers due to the lack of natural enemies; Microvoles feed on honey and larvae of ground bees and destroy their nests, so the number of ground bees decreases; Clover is pollinated by soil bees. When soil bees decrease, it will affect the pollination of clover, thus affecting the reproduction of clover, and the number of clover will decrease. Clover is the food of cattle, and the decrease of the number of clover will lead to the lack of food for cattle.
4. A: This kind of butterfly is called dead leaf butterfly, and its body color is basically the same as that of the surrounding fallen leaves, so it is not easy to be found by enemies, thus increasing the chances of survival.
5. A: Goats eat grass roots, which affects the growth of grass. Raising a large number of goats, if not properly managed, will destroy the grassland vegetation.
in the second quarter, organisms and the environment form an ecosystem
1, (1)×(2)×(3)√
2, D
3. Wild frogs feed on insects, while most insects, such as locusts and grasshoppers, feed on plants, which is harmful to crops. Therefore, preying on frogs will make harmful insects lose their natural enemies and multiply in large numbers, which will lead to a reduction in grain production.
4. It can be regarded as an ecosystem, because it generally conforms to the characteristics of the ecosystem, has the basic composition of the ecosystem and has certain adjustment ability.
5. Fill in the four boxes from top to bottom: producer; Animals; Decomposer; Sunlight, air, water, etc.
The biosphere in the third section is the largest ecosystem
1, D
2, and lynx (forest and grassland ecosystem);
Chinese alligator, swan with wart nose, cormorant-(river, wetland ecosystem)
Rana nigromaculata-(wetland, farmland ecosystem)
eel-(ocean, river ecosystem)
3, omitted
Unit 2.
3. When the opaque paper is thick, it can't be seen clearly, because the opaque paper blocks the light of the reflector.
4. Four mistakes: ① The eyepiece should not be wiped with gauze, but must be wiped with mirror-wiping paper; (2) observe the light first; (3) Under the binocular gaze, the lens barrel can be lowered until the slide specimen is very close; (4) When focusing observation, you should first turn the coarse quasi-focus screw to make the lens barrel rise slowly, and then turn the fine quasi-focus screw to make the image clearer after seeing the object clearly.
5. The microscope with the largest number of cells in the field of view is the No.3 mirror. Because the smaller the magnification of the microscope, the smaller the observed object image and the larger the observed field of view.
6. The simplest way is to turn the eyepiece. If the stain in the field of vision moves, it will be on the eyepiece, and vice versa.
in the second section, plant cells
1, (1)×(2)×(3)×(4)×
2. The edges of bubbles in the visual field are black and thick, with different sizes and round shapes. Cells are divided into cell membrane, cytoplasm and nucleus, and their forms are diverse.
3. The dyes used to dye temporary films can be divided into two categories. One kind has special dyeing function and is toxic to cells. For example, gentian violet can dye the nucleus purple and magenta acetate can dye the nucleus red, and the cells dyed by them have lost their activity. Another kind has special dyeing function but has no great influence on the activity of cells, which is called living stain, such as janus green, which can dye mitochondria. Generally speaking, staining the cells in the temporary specimen will inactivate the cells, but it is helpful for observation. When the cells to be observed remain active or the structures to be observed are obvious, staining is not necessary.
4. The juice obtained by squeezing fruit comes from vacuoles in cells.
Section III Animal Cells
1. Structure of animal cells (cell membrane, cytoplasm, nucleus, mitochondria)
Structure of plant cells (cell wall, cell membrane, cytoplasm, nucleus, chloroplasts, mitochondria, vacuoles)
2. The cells can be made into temporary pieces and observed by a microscope. If chloroplasts or vacuoles are found, the sample is. Because animal cells do not contain chloroplasts, they generally have no vacuoles. If chloroplasts are not found (because not all plant cells have chloroplasts), the biological sample can be placed in distilled water, taken out after a period of time, made into temporary pieces and observed. If cells are still found, it means that the sample cells have cell walls and should be plants. Because animal cells have no cell walls, they will absorb water and burst in distilled water.
cell life in the fourth quarter
1, (1)×(2)×(3)×
2, cell membrane-controlling substances in and out; Chloroplast-converts light energy into chemical energy;
mitochondria-transforming chemical energy into energy that cells can use; Nuclear-cell control center
3. When the mitochondria of human cells convert energy, it is necessary to decompose the nutrients (mainly glucose) in the cells by oxygen, so that the chemical energy in the nutrients can be converted into energy that can be used by human cells for the life activities of human cells. The functions of various organs and systems of critically ill patients are weakened, so the oxygen and nutrients obtained by critically ill patients through respiratory system and digestive system are reduced. Doctors often give oxygen and glucose solution to critically ill patients, which is to supplement oxygen and nutrients to patients, so that mitochondria in cells can work normally and patients can recover as soon as possible.
chapter ii how cells form an organism
the first section cells divide to produce new cells
1, (1)×(2)√(3)×
2,
3, cell division is the process of dividing one cell into two cells. When dividing, the nucleus is divided into two, then the cytoplasm is divided into two parts, each part contains a nucleus, and finally a new cell membrane is formed in the center of the original cell. Plant cells also form new cell walls. The most important change in cell division is the change of chromosome in the nucleus. Before cell division, the chromosome will be copied. With the division, the chromosome will be divided into two identical copies and enter two new cells respectively. The significance of this change is that there is genetic material DNA in the nucleus, and DNA is one of the components of chromosomes. Cell division realizes the replication and equalization of chromosomes, and thus the replication and equalization of genetic material DNA are realized. Therefore, it is ensured that the new cells produced by cell division contain the same genetic material as the original cells.
structural levels of animals in the second quarter
1. (1)×(2)√(3)√
2. The skin is distributed on the surface of human body and has a protective effect, indicating that there are epithelial tissues in the skin; If the skin is cut and we feel pain, it means that there is nerve tissue in the skin; The skin will bleed when it is cut, indicating that there is connective tissue in the skin.
3. Heart-muscle tissue; Salivary gland-epithelial tissue;
femur-connective tissue; Brain-nerve tissue
4,
Structural levels of plant in the third section
1,
2, D
3. Protective tissues are mainly distributed on the surfaces of various organs of the plant. Transport tissues run through roots, stems, leaves and other organs, and transport water and inorganic salts absorbed by roots to various parts of plants. If you pinch off the top of a branch of a plant, then the branch can't continue to grow up because there is meristem at the top of the branch.
4. Oranges are the fruits of plants with seeds in them. There are peels outside, including orange peel and orange petals, including protective tissue, nutritional tissue and transport tissue. Besides protective tissue and vegetative tissue, there are meristems in seeds.
5. The sieve tube located in the bark transports the organic matter produced by photosynthesis to other organs and tissues of the plant for utilization. If the bark is stripped, the other organs of the plant will die because they can't get the organic matter.
6. Compared with the structural levels of organisms, animals are more complicated than plants, which are directly composed of organs and have no system.
single-celled organisms in the fourth quarter
1, (1)×(2)×
2. Structurally, paramecium has basic structures such as cell membrane, cytoplasm and nucleus. From the biological characteristics, paramecium needs to get food from water, and contractile vacuole and collecting pipes can also collect and excrete excess water and waste in the body to maintain normal life activities. When paramecium is stimulated by the outside world, such as encountering obstacles, it can move to a relatively safe environment by constantly swinging the cilia on the surface membrane.
3, (1) A (←) B (→)
(2) Salt is an unfavorable stimulus to paramecium, so the paramecium on the side with salt particles should escape and swim to the culture liquid drops without salt particles; Gravy is a favorable stimulus for paramecium, so paramecium on the side without gravy will swim into the culture drops with gravy.
(3) paramecium is an organism that can respond to external stimuli.
4. The bear thinks that euglena is a plant, and the judgment is based on the chloroplast in the structure of euglena; MengMeng thinks that the reason why euglena is an animal is that euglena has eye spots and flagella can move. Through consulting the data, we know that euglena is a general term for living things, which is called Euglena in botany and protozoa in zoology. Therefore, euglena is a kind of unicellular eukaryote between animals and plants.
Unit 3 Green Plants in the Biosphere
Chapter 1 What are the green plants in the Biosphere
Section 1 Algae, Bryophytes and Pteridophytes
1. Algae (without differentiation of roots, stems and leaves)
Bryophytes (with short plants and no conducting tissues in stems and leaves)
Pteridophytes (with roots, stems and leaves) There are transport tissues in the body)
2. If the fish tank is not changed for a long time, the nutrients needed for the growth of algae plants in the fish tank will increase, and algae plants will multiply in large numbers, so the water in the fish tank will gradually turn green, and algae plants attached to the fish tank wall will form a green film.
3. Most bryophytes live in humid environment. Therefore, mosses often grow on the shady side of the trunk, but not on the sunny side.
4. Coal combustion will produce a lot of harmful gases, such as sulfur dioxide. Because the leaves of bryophytes have only one layer of cells, toxic gases such as sulfur dioxide can invade the leaf cells from the back and abdomen, which seriously threatens the survival of bryophytes. After the coal-fired power plant is completed, it is difficult to see green bryophytes around it.
5. Among algae, mosses and ferns, ferns have conducting tissues. The appearance of transport tissues greatly improves the ability of plants to transport water, inorganic salts and organic matter, thus enabling plants to live on land.
seed plants in the second quarter
1, (1)√(2)√(3)×
2, seed coat (protective embryo); Embryo (can develop into a new plant); Endosperm (stored nutrients)
3. Angiosperms generally have very developed transport tissues, thus ensuring the efficient transport of water and nutrients in the body; They can generally blossom and bear fruit, and the fruits can protect the seeds inside, and many fruits can also help the seeds spread. These characteristics of angiosperms make them the most widely distributed plant groups on land.
Chapter II Life of Angiosperms
Section I Seed Germination
1. Because the environmental conditions required for seed germination of different crops are not completely the same, suitable environmental conditions should be provided according to the requirements of different crops when sowing. Soaking seeds is to meet the requirements of seed germination for water, and fertilizing soil is to make the soil have enough air. Choosing different sowing time is to meet the different requirements of temperature for seed germination of different crops.
2. Seed germination needs a suitable temperature, so the temperature can be reduced when seeds are preserved; Seed germination needs a certain amount of water, therefore, attention should be paid to keeping the environment dry when preserving seeds; Seed germination needs sufficient air, so seeds can be preserved by sealing or introducing nitrogen to reduce the oxygen content in the air.
3. The germination of broad bean seeds has nothing to do with light conditions, tobacco seeds germinate under light conditions, and water spinach seeds germinate under light conditions.
in the second section, the growth of plants
1, (1)×(2)×(3)×(4)×
2, D 3, A
4, and the protection of root hairs can better absorb water.
5. (1) The input liquid may contain water and inorganic salts, which can replenish water and provide nutrition for plants to promote their growth.
(2) Needles for infusion should be inserted into the dredging tissues of trees.
6. It conforms to the principle of scientific farming. This agricultural proverb says that for crops, their survival, growth and harvest depend on the way and method of watering; The harvest of crops depends on the time, method and amount of fertilization. This shows the importance of water and fertilizer for agricultural production.
flowering and fruiting in the third section
1. (1)× (2)√2.
3. Cucumber, pumpkin and towel gourd are monoecious plants with different flowers, that is, on the same plant, some flowers are male and some are female. Generally, there are more male flowers than female. Those flowers that only bloom without fruit are male flowers.
Chapter III Water Cycle between Green Plants and Biosphere
1. (1)×(2)×(3)×(4)√
2. Because leaves will lose a lot of water through transpiration, saplings will die because of lack of water, so a lot of branches and leaves should be cut off.
3. (1) Avoid evaporation of water in the measuring cylinder to ensure that the reduction of water is absorbed by plants.
(2) The liquid level in the measuring cylinder with branch A inserted is lower than that in the measuring cylinder with branch B inserted. The reason is that branch A has leaves, which has strong transpiration and will reabsorb more water from the measuring cylinder. Branch b has no leaves, steamed