Junior high school 8th grade biology knowledge points
Major groups of animals
I. coelenterates
1. Common coelenterates include hydra, jellyfish, anemone, jellyfish and coral.
2. The representative animal of coelenterate: Hydra.
3. Living environment: In clean fresh water, the water flow is slow and aquatic plants flourish.
4. External morphology: tentacles, used for exploration and predation.
5, body: radiation symmetry (Hydra's body can only be divided up and down, not left and right, front and back, back.
The abdomen can be divided into several symmetrical two parts through the longitudinal axis of the body)
6. Internal structure: Hydra's body consists of endoderm and ectoderm. The cavity surrounded by endoderm is called digestive cavity, and there are stinging cells on ectoderm.
5. The main characteristics of coelenterates are: the body is radially symmetrical, there are stinging cells on the body surface, and there are mouths without anus.
6. Schematic diagram of hydra longitudinal section
Second, flat animals.
1. Common flatworms are duckweed, Clonorchis sinensis, Schistosoma japonicum and Taenia solium.
2. The representative animals of flatworms are: planarian.
3. Living environment: under the rocks in the clean stream.
4, external shape: the back and abdomen of the body are flat, and the sides of the body are symmetrical, also known as left-right symmetry.
5. There are no special digestive organs, and the reproductive organs are very developed. Most flat animals are parasitic in humans and animals.
6. The main characteristics of oblate animals: symmetrical sides of the body, flat back and abdomen, and no anus in the mouth.
Third, linear animals.
1. Common linear animals include roundworms, hookworms, filariasis and nematodes.
2. Representative animal: Ascaris lumbricoides
3, living environment: parasitic in the human small intestine, relying on sucking the semi-digested chyme in the small intestine for a living.
4, morphological structure: the body is cylindrical, the middle section is thicker, the ends are thinner, and there is a cuticle on the body surface.
5. Internal structure: The digestive tube is simple in structure, and the intestine is composed of only one layer of cells, but the reproductive organs are developed and there are no special moving organs.
6. Infection route of ascariasis: It is related to eggs.
(1) People drank raw water with eggs.
(2) eat vegetables stained with eggs.
(3) Take food with hands stained with eggs.
7. Prevention of Ascariasis
(1) Pay attention to personal hygiene first,
(2) Do not drink unclean raw water and vegetables.
(3) washing the fruit,
(4) Wash your hands before and after meals.
(5) Eggs should be killed before feces are used.
8. The main characteristics of linear animals: slender and cylindrical body; There are cuticles on the body surface, mouth and anus.
Fourthly, annelids.
1. Common annelids are earthworms, sand cicadas and leeches.
2. Representative animal: earthworm
3. Appearance: The body consists of many similar body segments, with a mouth in front and an anus in the back.
4. Belt: The front end is close to the belt and the back end is far away from the belt.
5. Touch the surface of the earthworm with your hand, and it feels rough and uneven. This is a bristle.
6, earthworm breathing: wet body wall
7. Movement: The coordination of bristles and muscles completes the movement.
8. The main characteristics of annelids: the body is cylindrical and consists of many similar segments; Bristles and wart feet help exercise.
9, the role of earthworm:
(1) loosen soil and improve soil fertility,
(2) It contains protein and fat, and has high nutritional value.
(3) medical use
(4) It is helpful to treat domestic garbage and eliminate environmental pollution.
Five, mollusks
1. Common mollusks are mussels, scallops, meretrix meretrix, probiotics, snails and squid.
2. Represents mollusk: mussel.
3. Living environment of mussels: in freshwater environment such as rivers and lakes.
4. mantle: protect the mussel software and secrete substances to form a shell. It is a bivalve with a shell.
5. Motor organ: foot
6, respiratory organs: gills
7. The main characteristics of molluscs: the surface of molluscs has a mantle, and most of them have shells; The moving organ is the foot.
Six, arthropods
1, the representative animal of arthropod: locust.
2. Insects are the most diverse animals among arthropods.
Spiders are not insects.
4. The body of grasshopper is divided into head, chest and abdomen. The head is responsible for feeling and eating, and the chest is the center of exercise.
5, breathing: the valve of the abdomen
6. Exoskeleton: (1) protects the body, (2) prevents evaporation of water in the body.
7. The main characteristics of arthropods: tough exoskeleton on the body surface; The body and appendages are segmented.
8. The relationship between arthropods and humans: (1), providing food (2) pollination (3) medicinal value.
Seven, fish
1. Vertebrates have spines, but invertebrates have no spines.
2. Four big fish:? Grass carp?
3. Fish can live in water: First, they swim to get food and resist enemies; The second is to be able to breathe in the water.
4. Structural characteristics of fish suitable for swimming.
(1) Body shape: streamlined, which can reduce the resistance of water when swimming.
(2) Body color: the upper part is deep and the lower part is shallow, which is a protective color and is not easy to be discovered by the enemy.
(3) Body surface: The body surface is covered with scales to protect the body, and there is mucus on the surface to reduce the resistance of water.
(4) sideline: sense the water flow and determine the direction.
(5) Respiratory organs: Below the gill cover are gills, which are composed of many thin gills, and the gills are densely covered with rich capillaries, so they are bright red.
(6) The fish mouth and the back edge of gill cover are alternately opened and closed, which is mainly used for breathing.
(7) Exercise: Swimming through the swing of tail and trunk and the coordination of fins.
5. The main characteristics of fish: living in water, covered with scales, breathing through gills, swimming through the swing of tail and trunk and the coordination of fins.
Eight, amphibians
Common amphibians are frogs, bullfrogs, toads, pears and salamanders.
2. Representing animals; frog
Frogs are developed from tadpoles, which are like fish in both external morphology and internal structure.
4. Frog larvae tadpoles breathe with their gills.
5, the color of the frog is similar to the surrounding environment, which is a protective color.
6. The frog's bare skin is soft and moist, and it can secrete mucus.
7, forelimbs; Short, can support the body, strong hind legs, poof between papers, suitable for jumping on land, but also suitable for swimming in the water
8. Breathing: lung and skin assist breathing.
9. Body temperature: variable temperature
10, the main characteristics of amphibians: larvae live in water and breathe through gills, while adults mostly live on land, and they can swim in water, breathe through lungs and breathe through skin.
Nine, reptiles
1, the common reptiles are lizards, turtles, snakes, turtles, crocodiles and so on.
2, on behalf of animals: lizards
3. Living environment: hillside, field, grassland and bushes.
4, body surface: the body surface is dry and covered with horny scales, which not only has a protective effect, but also reduces the loss of water in the body, which is conducive to adapting to land life.
5, breathing: lungs
6. Body temperature: variable temperature
7. Breeding: Laying eggs
8. The reproduction and development of lizards depend on the water environment and live on land all their lives.
9. The main characteristics of reptiles: the body surface is covered with horny scales or nails, breathing with lungs, laying eggs on land, and the egg surface has tough eggshells.
Bird
First, not all birds can fly, such as ostriches and penguins.
Second, the morphological structure and physiological characteristics of domestic pigeons suitable for flying life
1, the fuselage is streamlined to reduce the air resistance during flight.
2. The forelimbs of domestic pigeons become wings, with large positive feathers, which are flying organs.
3, long neck: flexible rotation, flexible expansion, can make up for the lack of forelimbs.
4, long bones are hollow, there is air inside, you can lose weight.
5, muscular: attached to the sternum, affecting the two wings to complete the flight action.
6, large appetite, strong digestion; Short rectum can excrete feces in time and lose weight.
7. Breathing: Breathe with the lungs, and the airbag assists the breathing of the lungs. Breathe once and breathe twice in the lungs, which is double breathing.
7, body temperature: constant temperature. Fish, amphibians and reptiles are warm animals whose body temperature changes with the change of environment.
Xi。 mammal
Common mammals are whales, pigs, cows, sheep, horses, rabbits and wolves.
Whales are mammals, not fish.
3. Body temperature: constant (animals with constant body temperature include birds and mammals)
4. Reproductive mode: viviparous and breastfeeding.
5. Benefits of viviparous and breastfeeding: It improves the survival rate of offspring.
6, teeth: incisors, molars, canine teeth differentiation.
7. The main characteristics of mammals: body surface coat; Viviparous, breastfeeding; Teeth are divided into incisors, molars and canines.
microorganism
gemmule
1, the bacteria are made by Levin? Hook found it.
2、? Father of microbiology? It's Pasteur of France.
3, Pasteur used? Goose neck bottle? Experiments show that bacteria are not naturally produced, but are produced by pre-existing bacteria.
4. Bacteria: tiny
5, bacterial morphology: cocci, bacilli, spirillum.
6. Structure of bacteria: as shown in the figure.
(1) Bacteria are cells. Single-celled organisms.
(2) There is no nucleus formed, only the concentrated area of DNA.
(3) Without chloroplasts, most bacteria can only live with ready-made organic substances and decompose them into simple inorganic substances. They are decomposers in the ecosystem.
(4) The structure of bacteria includes cell wall, cell membrane, cytoplasm, aneuploid, DNA concentration area and no chloroplast. The special structure includes capsule and flagella.
7. Bacterial reproduction: fission reproduction
8. The dormant body of bacteria is spore, which has strong resistance to adverse environment.
fungus
1. Classification of fungi: unicellular fungi and multicellular fungi.
(1) Yeast (unicellular fungus).
(2) Mold: Penicillium and Aspergillus (multicellular fungi).
2. The structure of yeast: cell wall, cell membrane, cytoplasm (without chloroplast), vacuole and nucleus.
3. Mold (Penicillium, Aspergillus) Every cell of mold has a cell wall, a cell membrane, a cytoplasm and a nucleus.
(1) Penicillium: It is composed of upright hyphae, vegetative hyphae and apical spores, and it is broom-shaped and turquoise.
(2) Aspergillus: It consists of upright hyphae, vegetative hyphae and apical spores, which are radial.
? Spores Is it an upright mycelium? This is vegetative mycelium.
A, Penicillium is broom-shaped; B. Aspergillus is radial.
4. All nucleated organisms belong to eukaryotes, such as fungi, plants and animals. Without nuclei are prokaryotes, such as bacteria.
4. Fungal reproduction: spore reproduction.
5. Nutrition mode: heterotrophic
virus
1, virus development history:1At the end of September, a virus was discovered in ivanovski.
2, size: smaller than bacteria, smaller than cells, can only be expressed in nanometers.
3. Observation tool: electron microscope
4, lifestyle: must be born in the living cells of other organisms, can not live independently.
5. Structure of the virus: The virus has no cell structure, and only consists of the shell and internal genetic material of protein.
6. Virus type:
(1) Plant virus (parasitic only on plants)
(2) Animal virus (specially parasitic on animals)
(3) bacterial viruses (also known as bacteriophages, which are specially parasitic in bacteria)
7, virus replication: self-replication, relying on genetic information in their own genetic material, using substances in cells to create new viruses.
8. Viruses usually turn into crystals when they leave living cells.
9, the relationship between virus and human:
Harmful: make people sick
Advantages: medicine, biological control, etc.
8th grade's Biology Learning Method in Junior Middle School
First, prioritize. Mathematics, Chinese, English and physics should be arranged as key points. In addition to listening carefully in class, 70% of the energy after class should be spent on these main courses. When you arrive in 8th grade, every main course should have an extra-curricular tutorial, and it is also necessary to do some exercises after class. In the second half of the semester, 8th grade will graduate in geography and biology, so you can have a good class and master the necessary knowledge. Politics and history are open-book exams. Besides textbook knowledge, we should also pay more attention to current events.
Second, we should arrange the study time reasonably. People have the best memory in the morning and are suitable for reading English and memorizing words. During the day, self-study classes are arranged for mathematics and physics, and the efficiency of solving problems is higher at this time. The rest of the time will be reserved for Chinese, so you can read more extracurricular books. When you meet good articles and paragraphs, you should copy them down and accumulate materials, so that writing will be easier. When reviewing at night, don't be tired. You can listen to music, do some less intense indoor sports, relax, and your learning efficiency will be greatly improved.
Third, enter each prepared class and listen to the class with interest, questions and purpose. Prepare what? That is, according to the course arrangement, preview the weak courses in a targeted manner. When previewing, we should make clear the content of the next class, which is clear, which is vague and which is not understood, so as to determine the focus of listening. Summarize after class, summarize the framework of knowledge, and then do related exercises.
Fourth, get rid of the embarrassing feeling, communicate with classmates more, and find other people's good ideas, methods and mentality in the discussion. This kind of close communication will make you integrate with everyone and reduce the psychological pressure of learning. At the same time, relax your learning attitude, and the effect of attending classes will be improved quickly.
Fifth, study? Xi？ The role of learning determines whether the result of learning has a good result. Read some related counseling materials and do some related exercises after class every time. There are a lot of counseling materials now, which one is better? Which is suitable for your situation? Take a quick look at the counseling materials shelf in the bookstore and use the one you feel comfortable with. If you are still not sure, you can consult a substitute teacher.
Sixth, carefully arrange review, develop good study habits and prepare more notebooks at ordinary times. Write down the questions you don't understand and the problems that are easy to make mistakes in time. In this way, review can be targeted and orderly.
Suggestions on 8th grade's Biology Learning in Junior Middle School
First, fall in love with biology
Interest is the key to learning. The research object of biology is all kinds of living things, including plants, animals, bacteria, fungi, viruses and human beings themselves. Students can observe and learn more about these creatures in their daily lives, and the physical objects are the best, and they can also be obtained from books, videos and other materials.
Second, contact life.
The biological knowledge in books is dead and limited, and the real biological classroom is in life. Students should be good at finding problems and thinking when observing biology. When learning biological knowledge, we should be related to these facts, which will help us to understand and remember the theoretical knowledge in the textbook quickly and accurately, and also help us to improve our ability to solve problems and truly apply what we have learned.
Third, understand before remembering.
Biology belongs to science, so you can't learn by rote. There are many biological concepts such as cells, tissues and chromosomes in biological knowledge. When learning this part of knowledge, we should first understand: understand the connotation of various concepts, such as cells are the basic units of organisms; Understand the relationship between concepts, such as multiple cells can form tissues. Only by understanding first can we remember better.
Fourth, be good at summarizing.
Summarizing knowledge can better clarify the context of knowledge and lay the foundation for effective review.
For example, after understanding bacteria, we can compare the structure of bacteria with that of animals and plants, and analyze their similarities and differences, so as to facilitate the memory of knowledge and the fungi and viruses behind them. Knowledge points with similar characteristics like this can be summarized in time.
Five, familiar with the basic ideas of biology
Knowing the basic idea of biology, that is, the central idea, can learn biological knowledge faster and more accurately.
(1) Structure and function are unified: if you know its structure, you will know its function; Each function must have a corresponding structure.
(2) the holistic view of biology: no matter cells, tissues, organs, individuals, or even populations and communities, they all reflect the characteristics of wholeness.
(3) The viewpoint of biological evolution: biological evolution follows the law from simple to complex, from aquatic to terrestrial, and from low to high.
(4) Ecological viewpoint: The basic content is that biology and environment are interactive, interdependent and mutually restrictive. Biology and environment are an inseparable and unified whole.
In short, learning is not one thing? Simple things? . To learn biology, we must first love this subject, regard learning as a pleasure, and have the spirit of diligence and willingness to pay. If we can do this, I believe it is not a problem to learn biology well.
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