Theme 1 Biology and Biosphere
Principle of control experiment: univariate principle (i.e. control variable method). For example, to discuss the influence of light on the life of mice and girls, all other conditions are the same except light.
ecosystem
Organisms and their living environment constitute an ecosystem. Such as: a pond, a meadow (note: all the fish in the river ... are not an ecosystem). There are various types of ecosystems on the earth, such as oceans, forests, grasslands and farmland. The largest ecosystem on earth is the biosphere.
The composition of ecosystem: biological part and abiotic part (that is, living and environment).
The biological part includes: producers-plant consumers-animal decomposers-bacteria, fungi and earthworms.
Plants produce organic matter through photosynthesis, consumers eat plants directly or indirectly, decomposers decompose animal and plant feces and remains, and decompose organic matter into inorganic matter, which is absorbed by plants and can be recycled. Producers, consumers and decomposers are interrelated and interdependent.
3. The starting point of the food chain is the producer and the end point is the highest consumer. The food chain does not include abiotic components and decomposers; The arrow indicates the predator-prey relationship and points to the predator (the strong); The matter and energy of the ecosystem flow through the food chain and food web.
Some harmful substances will accumulate through the food chain. (such as pesticide DDT)
5. The ecosystem has a certain ability of automatic adjustment. There are many kinds of creatures, such as forests and oceans, which have strong adaptability.
6. Biosphere: Only the places suitable for living things on the earth are the biosphere, not the whole earth is a biosphere, so the biosphere is the sum of all living things on the earth and their living environment. (bottom of atmosphere, most hydrosphere, lithosphere surface)
Topic 2 Biology and Cells
Structure and use of microscope
Important structure: eyepiece, lens barrel, objective lens, light hole, aperture (on shutter), coarse focusing screw, fine focusing screw, converter, objective table and reflector.
Use steps
Pick up and place the mirror, and install the eyepiece and objective lens.
Adjust the magnification of the microscope
Turn the converter so that the low-power objective lens is aimed at the light hole.
Aim the larger aperture at the aperture, with the left eye staring at the eyepiece and the right eye open. Turn the reflector to make the light reflect into the lens barrel through the light hole, and you can see a bright field of vision through the eyepiece. (Note: Low power mirror, choose aperture, see with left eye, open with right eye, choose reflection. )
(3) Observation
1, put the slide specimen on the stage and hold it down with a flat clamp, with the specimen facing the center of the light hole.
2. Turn the coarse focusing screw and slowly lower the lens barrel until the objective lens is close to the slide specimen. Keep your eyes on the objective lens to prevent it from touching the slide specimen.
3. Look into the eyepiece with your left eye, and turn the coarse focus screw at the same time to make the lens barrel rise slowly until you can see the object clearly. Then turn the fine focusing screw slightly to make the image of the object clearer. (Note: First down, then up, first thick, then fine)
(4) Replace the high-power mirror
Move the specimen to the center of the field of view, then rotate the converter to replace the high-power objective lens, adjust the aperture or mirror to get more light, and then rotate the fine-tuning focus screw until the specimen image is clear.
Test center 1: magnification = eyepiece magnification × objective magnification.
Test site 2: What you see in the eyepiece is an inverted image. The way to move the object image to the center of the field of view is to move the slide specimen to the side where the object image is located. (For example, if you find a cell in the upper right of the field of vision, you should move it to the center of the field of vision, and the slide should be moved to the upper right. In the process of moving, it can be observed from the eyepiece that the moving direction of the object image is moving to the lower left of the center of the field of view. )
Test site 3: From low-power lens to high-power lens, the cells will become larger, the number will decrease, and the field of vision will darken.
Detection site 4: stains can only be on eyepiece, objective lens or specimen.
Types of slide specimens
Slice-Cut the material (find the word "cut").
Smear-The material must be liquid.
Filming-does not meet the above two kinds, commonly used words such as "pick", "scrape" and "tear".
The making process of animal and plant slide specimens: wiping, dripping, taking, spreading, covering, dyeing and sucking.
Test site 1: Plant materials are dripped with clear water (with cell walls), and animal materials are dripped with physiological saline.
Test site 2: cover glass with inclined cover to drive away bubbles. If bubbles appear, gently tap the glass cover with the tip of a pencil to drive it away. Bubbles are bright in the middle, with black edges, which will deform when pressed, while cells have structures in the middle.
Test center 3: The dyeing step is to drop the dye solution on one side of the cover glass, and then suck it on the other side with absorbent paper. (dye first and then suck. Of course, some cells can be observed directly without dyeing. )
honeycomb structure
Except viruses, all living things are composed of cells, which are the basic units of biological structure and function.
Plant cells: cell wall, cell membrane, cytoplasm, nucleus, chloroplast and vacuole.
Animal cells: cell membrane, cytoplasm and nucleus.
Bacterial cells: cell wall, cell membrane, cytoplasm and DNA region.
Fungal cells: cell wall, cell membrane, cytoplasm and nucleus.
Virus: It has no cell structure, can't live independently, and can only be parasitic in living cells.
Cell membrane can control the entry and exit of substances; Plants have energy converters in cytoplasm, chloroplasts and mitochondria, while animals have mitochondria. The nucleus is the genetic information base and control center of cells.
Cell division increases the number of cells, and the most obvious change during division is chromosome. Division process: the chromosomes in the nucleus are copied first, then split into two, the nucleus is split into two, and the cytoplasm is split into two, forming a cell membrane in the center of the cell, and plant cells also form new cell walls.
Cell differentiation increases cell types and forms different tissues.
The structural level of plants: cells → tissues → organs → plants.
Four kinds of organizations: conservation organization, transportation organization, nutrition organization and meristem organization.
Six organs: roots, stems and leaves are vegetative organs, while flowers, fruits and seeds are reproductive organs.
The structural levels of animals and people: cells → tissues → organs → systems → animal bodies and human bodies.
Four kinds of tissues: epithelial tissue, nerve tissue, muscle tissue and connective tissue (such as blood)
Organs: such as skin, brain, etc. Every organ is dominated by some kind of tissue. For example, the main tissue of skin is epithelial tissue, the main tissue of brain is nerve tissue, the main tissue of heart is muscle tissue, and the tissue of femur is connective tissue.
The important difference between animals and plants is that animals have systems and plants have no systems.
Theme 3: Green Plants in the Biosphere
Main groups of plants: algae, mosses, ferns and seed plants (gymnosperms, angiosperms).
Algae: mostly live in water, with simple structure and no differentiation of roots, stems and leaves, such as Chlamydomonas and kelp;
Bryophytes: living in dark and humid land, with stems and leaves, no roots, no dredging tissue in the stems and leaves, and the breeding process can not be separated from water, such as cucurbitaceae and liverworts;
Pteridophyte: Living in dark and humid land, it has differentiation of roots, stems and leaves, and dredging tissues in the body, such as ferns.
Gymnosperms: Suitable for all kinds of environments, with developed roots and leaves, bare seeds and sterile capsules. Such as pine, cypress and ginkgo.
Angiosperms: Suitable for all kinds of environments, they have six organs: root, leaf, flower, fruit and seed, and the seed has pericarp, which is the most evolved group in the plant kingdom. Such as corn, rice and apples.
Conditions of seed germination
Self-conditions: the seeds are alive, have passed the dormancy period, mature, complete embryos and sufficient nutritional reserves.
(Embryo includes hypocotyl, radicle, embryo and cotyledon)
Environmental conditions: suitable temperature, certain humidity and sufficient air. (No lighting required)
The life of green plants needs water and inorganic salts. Among them, the most demanding inorganic salts are nitrogen, phosphorus and potassium.
Function of water and inorganic salts: an important component of plants, in which water is an important substance of photosynthesis, and inorganic salts can only be absorbed and transported if they are dissolved in water. Absorption site: the root hair area of the root, also called mature area. Transportation structure: pipeline. Application in production: rational irrigation and fertilization.
Transpiration: transpiration of plant leaves loses most of the water. The ability of plants to absorb water and inorganic salts during transpiration.
chloroplast
light
5. Photosynthesis: The raw materials of photosynthesis are CO2 and water, the conditions are illumination, the place where photosynthesis takes place is chloroplast, and the products are organic matter and oxygen. Photosynthesis: carbon dioxide+water+oxygen+organic matter (energy storage)
The essence of photosynthesis is to use inorganic substances to synthesize organic substances, store energy and release oxygen.
The significance of photosynthesis: the source of organic matter needed by all living things and human beings (the required organic matter is finally provided by green plants); Energy sources needed by all living things and human beings (most of the energy on the earth comes from solar energy eventually); The source of oxygen for all living things and human beings (to make the contents of oxygen and CO2 in the atmosphere relatively stable and maintain the balance of carbon and oxygen).
6, the application of photosynthesis:
Reasonable close planting, three-dimensional planting, such as beans hanging all over the body, sweet potatoes drilling down; Crops are kept in the greenhouse in order to increase the temperature during the day and enhance photosynthesis, and decrease the temperature at night to reduce respiration, that is, to enhance the temperature difference between day and night and accumulate sugar in crops; Increase CO2 gas fertilizer and photosynthetic raw materials; Prolonging the illumination time and increasing the accumulation of photosynthetic products.
7. Breathe:
The raw materials of respiration are organic matter and oxygen, the place of respiration is mitochondria, and the products are CO2 and water.
The essence of respiration is to decompose organic matter into inorganic matter and release energy. Significance: providing energy for various life activities of organisms. (Note: Plants also need to breathe)
Theme 4: Human nutrition
Six nutrients needed by human body: sugar, fat, protein, water, inorganic salts and vitamins.
Energy substances: sugar, fat, protein. The most important and direct energy sources of human body are sugar and fat, and protein constructs cells.
The most common component of human body is water, which accounts for about 70% of body weight.
Inorganic salts: iron deficiency can lead to anemia, and calcium deficiency can lead to osteoporosis or rickets. Eat more meat, fish, milk, eggs and beans. Iodine deficiency can lead to dementia or neck diseases, and iodized salt and seaweed can prevent it.
Vitamins: night blindness A, beriberi B, bad blood C, rickets D.
Composition of digestive system: digestive tract and digestive glands.
Digestive tract: oral cavity, stomach, small intestine, large intestine and anus. (food passage)
Digestive glands: salivary glands, stomach glands, intestinal glands, pancreas and liver. The liver is the largest digestive gland.
A place to digest food:
There are salivary glands in the mouth, which can secrete saliva, among which salivary amylase can preliminarily digest starch.
The stomach has gastric glands, which can secrete gastric juice, among which pepsin can preliminarily digest protein.
There are intestinal glands in the small intestine, which can secrete intestinal juice, which contains enzymes for digesting sugar, protein and fat. Pancreatic juice secreted by the pancreas also flows into the small intestine, which also contains enzymes for digesting sugar, protein and fat. In addition, the liver secretes bile and stores it in the gallbladder. As the saying goes, bile finally flows into the small intestine. Although it does not contain digestive enzymes, it can emulsify fat.
The small intestine contains the most kinds of digestive juice and digestive enzymes, so it is the main place for digestion.
Starch digestion: firstly, it is decomposed into maltose by salivary amylase in the mouth, and finally into glucose in the small intestine.
Protein's digestion: firstly, it is preliminarily decomposed by pepsin in the stomach, and finally it is decomposed into amino acids in the small intestine.
Digestion of fat: fat is broken down into glycerol and fatty acids in the small intestine.
Absorption process of nutrients: nutrients enter blood vessels.
Stomach: Absorb a small amount of water, inorganic salts and alcohol.
Large intestine: a small amount of water, inorganic salts and some vitamins.
Small intestine: glucose, amino acids, glycerol and fatty acids, water, inorganic salts and vitamins.
Conclusion: Small intestine is the main absorption site.
Small intestine is suitable for nutrient absorption: the small intestine is very long, with many annular folds and villi on the inner wall, and the villi are rich in capillaries.
Topic 5: Transportation of human substances
The composition of human circulatory system: blood, blood vessels and heart.
Blood consists of plasma and blood cells.
Plasma is a yellowish translucent liquid, and its main components are water, inorganic salts and protein. , which has the function of transportation.
Blood cells: red blood cells (seedless, bilateral concave, oxygen delivery), white blood cells (nucleated, largest individual, immune function), platelets (seedless, smallest individual, hemostasis and coagulation).
How to read the blood test sheet? Fewer red blood cells than normal: anemia; More white blood cells than normal: inflammation.
The direction of blood flow in blood vessels: from arteries to capillaries and back to veins.
Arteries: thick wall, high elasticity, fast blood flow and deep distribution.
Vein: thin wall, small elasticity, slow blood flow and shallow distribution.
Capillary: the thinnest wall has only one layer of cells; The lumen is the smallest, allowing only red blood cells to pass through in a single file; The blood flow rate is the slowest, which is conducive to material exchange with tissues and cells.
heart
Structure: four chambers (upper chamber and lower chamber); Direction of blood flow (out of the room into the room)
Four major blood vessels: left ventricle → aorta, pulmonary vein → left atrium, right ventricle → pulmonary artery, superior and inferior vena cava → right atrium.
blood circulation
Arteries-transport blood from the heart to all parts of the body. Thick wall, high elasticity and fast blood flow.
boat
Veins-send blood back to the heart from all parts of the body. Thin wall, small elasticity and slow blood flow.
(There is a venous valve to prevent blood from flowing back)
Capillary-connected to the smallest arteries and veins. The wall of the tube is very thin and consists of a flat layer of epithelial cells, with the slowest blood flow. The lumen is the smallest, and red blood cells pass through in a single file. It is convenient for blood to exchange substances with tissues and cells.
Wall: It is composed of muscle tissue (the ventricle is thicker than the atrium and the left ventricle is thicker than the right ventricle).
Left atrium: communicating with pulmonary vein.
Right atrium of heart: communicating with superior and inferior vena cava.
Cavity: left ventricle: communicating with aorta.
superior vena cava
Right ventricle: communicating with pulmonary artery
4. Heart function: the power organ of blood circulation.
inferior vena cava
atrio-ventricular valve
Arterial valve
Valve: atrioventricular valve (located between atrium and ventricle, only facing ventricle) ensures blood flow in a certain direction.
Arterial valve (located between the ventricle and the artery, only open to the artery)
Systemic circulation: left ventricle → aorta → capillary network in all parts of the body → superior and inferior veins → right atrium.
5, blood circulation (arterial blood-> venous blood)
Pulmonary circulation: right ventricle → pulmonary artery → pulmonary capillary network → pulmonary vein → left atrium.
(venous blood-→ arterial blood)
6, the difference between arterial blood and venous blood:
Arterial blood: rich in oxygen and bright red in color. (Hemoglobin binds to oxygen)
Venous blood: low oxygen content, dark red color. (Separation of Hemoglobin from Oxygen)
7. There are four blood types: type A, type B, type AB and type O. The principle of blood transfusion is to input the same type of blood. In an emergency, type O blood is a "universal donor" and type AB blood is a "universal recipient".
8. Adult blood volume is about 7-8% of body weight. Donating 200-300ml blood each time does not affect health. /kloc-citizens aged 0/8-55 donate blood voluntarily.
(4) the human respiratory system
1, the human respiratory system consists of respiratory tract and lung.
Respiratory tract: the function of warming, moistening and cleaning air.
Lung: the main organ of the respiratory system and the place for gas exchange.
2. Gas exchange between alveoli and blood, and gas exchange between blood and tissues and cells:
(oxygen)
(oxygen)
Alveolar blood tissue cells
(carbon dioxide)
(carbon dioxide)
3. Air quality and health
1) Air quality affects human health, and pollutants in the atmosphere are extremely harmful to human health.
Harmful substances can cause respiratory diseases.
2) Understand the local air quality and the causes of local air pollution.
Measuring dust particles in the air
(5) the human nervous system
1. Composition of nervous system: It consists of brain, spinal cord and its nerves.
Brain: There are many nerve centers such as sensation, movement and language in the cerebral cortex.
Cerebellum: make movements coordinate accurately and keep balance.
Brain stem of central nervous system: it regulates life activities such as heartbeat and breathing.
2. Spinal cord of nervous system: it has conduction and reflection functions.
Cranial nerve: Sensory organ distributed in the head and emanating from the brain.
Peripheral nervous system
Spinal nerve: issued by the spinal cord and distributed in the skin and muscles of the trunk and limbs.
3. Neurons are the basic units that constitute the structure and function of the nervous system. (also called nerve cells)
4. The basic way of neuromodulation is reflex. Reflection is accomplished by a reflex arc. (reflex arc is the structural basis of reflection)
Reflex arc consists of receptor → afferent nerve → nerve center → efferent nerve → effector.
Simple reflex (unconditional reflex): innate. Such as shrinking hands, blinking, urinating and jumping knees, eating prunes and secreting saliva.
Step 5 reflect
Complex reflex (conditioned reflex): acquired. If you listen to the password, you think that Mei wants Mei to secrete saliva, but you are scared.
Note: The reflection related to language and writing is unique to human beings.
(6) Hormone regulation
1. Location and name of main endocrine glands in human body: pituitary, thyroid, islet, adrenal gland, gonad and thymus.
2. Hormone: chemical substances secreted by endocrine gland cells that have special effects on the body.
3. Pituitary gland: secretes growth hormone, thyroid stimulating hormone and gonadotropin, which can regulate the activities of other endocrine glands.
4, growth hormone, thyroid hormone, insulin:
Too little gland function and too much growth hormone. Pituitary regulates human growth and development: dwarfism: gigantism; Adults: acromegaly thyroid hormone thyroid promotes metabolism, growth and development, and improves the excitability of nervous system: dementia; Adult: thyroid insufficiency, endemic goiter adult: hyperthyroidism insulin islet regulates glucose metabolism diabetes hypoglycemia.
5. Relationship between nerve regulation and hormone regulation: The regulation of human life activities is mainly regulated by the nervous system, but also by hormones.
Six, the movement and behavior of animals
1, the diversity of animal movements
Animals can actively and purposefully change their spatial position quickly through exercise. Animals move in various ways, birds and insects can fly or slide; Terrestrial animals mainly walk, run, jump and climb; Aquatic animals mainly swim. Animals actively adapt to the environment through exercise. In the long process of evolution, animals gradually formed a series of characteristics to adapt to the environment through exercise, and improved their ability to adapt to the environment. Animals can also quickly move to more suitable habitats and breeding sites through sports, which is conducive to their own survival and racial reproduction. )
2. The movement of animals depends on a certain structure.
Multicellular animals rely on unique motion organs to exercise, and single-celled animals also have their own motion structures.
4. Composition of vertebrate motor system
The motion system of vertebrates consists of three parts: skeleton, osseointegration and skeletal muscle.
When skeletal muscle contracts under nerve stimulation, it will affect the movement of bones around joints and produce movement. Exercise is not only accomplished through the coordination of all parts of the exercise system, but also through the control and adjustment of the nervous system and the supply of energy.
5, the energy source of animal movement
6. Animal behavior
(1) Main types and examples of animal behavior
Animal behavior is complex and diverse, including foraging behavior, defensive behavior, reproductive behavior, migration behavior, migration behavior, social behavior and so on.
(2) Concepts and examples of animal innate behavior.
Innate behavior is the behavior that animals are born with and controlled by genetic material. Such as: bees collecting honey, ants building nests, spiders weaving webs, bird migration, etc.
(3) Concepts and examples of acquired behavior of animals.
Acquired behavior is not innate, but gradually established through the accumulation of life experience and "learning" in the process of animal growth. Such as: dogs do arithmetic, dolphins head, monkeys write, etc.
(4) Social behavior characteristics of animals:
(1) form a certain organization; ② Division of labor and cooperation among members; (3) Some even form a grade.
Seven, biological reproduction, development and inheritance
(A) the reproduction of plants
1, biological asexual reproduction mode
Asexual reproduction refers to the reproductive mode in which new individuals are directly produced by the mother without the combination of bisexual reproductive cells. Such as fission propagation, budding propagation and vegetative propagation.
2. Plant asexual reproduction methods: cutting, grafting, layering, tissue culture, etc.
Grafting is to connect the buds or shoots of one plant to another plant, so that they can be combined into a complete plant. Grafted buds or branches are called scions, and grafted plants are called rootstocks. When grafting, the cambium of scion and rootstock must be closely combined, and the cells split from cambium can heal together.
4. Sexual reproduction process of plants
Plant sexual reproduction refers to the process that a parent produces germ cells, which combine with hermaphroditic germ cells to become fertilized eggs and then develop into new individuals. The process of sexual reproduction in angiosperms includes flowering, pollination, fertilization, fruiting and seed formation.
Note: The difference between sexual reproduction and asexual reproduction: whether the germ cells are combined or not.
(2) human reproduction and development
1. Male reproductive system: testis (main reproductive organ)-producing sperm and secreting androgen.
Vasectomy-transporting sperm
2. Female reproductive system: ovary (the main reproductive organ)-produces eggs and secretes estrogen.
Oviduct transports egg cells
Uterus-the place where embryos and fetuses develop.
3, reproductive process:
About 280 days
Division and differentiation
Ovary → egg cell
→ fertilized egg → embryo → fetus → newborn (baby)
Testis → Sperm
4. Embryonic development and nutrition
Development: fertilized egg → embryo → fetus → baby (the starting point of human embryo development is fertilized egg, and the process of development is the process of cell division and differentiation)
Nutrition: the nutrition needed in the early stage of embryonic development comes from egg yolk; The nutrients needed for embryo development in uterus are obtained from mother through placenta and umbilical cord. Placenta-the place where the fetus and mother exchange substances.
(3) the relationship among chromosomes, DNA and genes
Chromosomes are mainly composed of protein and DNA, and DNA fragments with specific genetic information on chromosomes are called genes. There is generally only one DNA molecule on each chromosome, and there are many genes on each DNA molecule. DNA is the main genetic material, and genes determine the characteristics of organisms.
(d) Biological characteristics are controlled by genes.
1, the concept of genetic traits
Hereditary traits refer to the morphological and structural characteristics, physiological characteristics and behavior patterns of organisms that can be inherited. Relative traits refer to different forms of expression of the same trait of an organism. Such as: different colors of rabbit hair, white, black, gray and so on.
2. Genes control biological characteristics.
Biological traits are controlled by genes, and genes determine traits. Genes generally exist in pairs in somatic cells. Some pairs of genes are dominant and recessive. Genes that control dominant traits are called dominant genes (represented by uppercase English letters), and genes that control recessive traits are called recessive genes (represented by lowercase English letters). Genes are passed from parents to children through germ cells (or sperm and egg cells).
3. Human sex determination: determined by sex chromosomes.
People's sex determination is XY type. The female sex chromosome is XX, and only one kind of egg cell containing X chromosome is produced. The male sex chromosome is XY, which can produce two types of sperm: X chromosome or Y chromosome.
Chromosome composition of human somatic cells: male: 22 pairs +XY.
Female: 22 pairs +XX
Chromosome composition of sperm cells: 22 +X or 22+Y.
Chromosome composition of egg cell: 22+X.
4. Measures for prenatal and postnatal care: The measures for prenatal and postnatal care include prohibiting consanguineous marriage and promoting genetic counseling and prenatal diagnosis.
Genetic diseases are generally caused by changes in genetic material or controlled by pathogenic genes. Between close relatives, many genes come from the same ancestor, so it is more likely to carry the same pathogenic gene. The prevalence of genetic diseases of children born to close relatives is much higher than that of children born to non-close relatives.
(5) Biological variation
1, the concept of biological variation: variation refers to the differences between biological parents and offspring and between offspring individuals.
2. The difference between genetic variation and non-genetic variation.
Genetic variation refers to the variation caused by the change of genetic material and can be passed on to future generations.
Non-genetic variation refers to the variation of organisms under different environmental conditions, and the genetic material has not changed and will not be passed on to future generations.
3. The application of genetic breeding in practice.
Breeding methods: cross breeding, transgenic methods, etc.
Eight. biodiversity
1, the significance of protecting biodiversity
Biodiversity mainly includes species diversity, genetic diversity and ecosystem diversity.
The protection of biodiversity includes in-situ protection and ex-situ protection. At the same time, we should strengthen education and legal management. In-situ conservation is the most effective measure to protect biodiversity and the necessary means to save biodiversity. Nature reserves are the main places to protect biodiversity in situ. Ex situ conservation is a supplement to in situ conservation. Botanical gardens, zoos, aquariums and gene banks are the main means to implement ex-situ conservation. The threat to biodiversity is mainly reflected in the acceleration of species extinction.
There are many reasons for the loss of biodiversity. The rapid growth of population is the main reason for destroying or changing wildlife habitat and overusing biological resources. In addition, environmental pollution is also an important cause of biodiversity loss.
2. Basic viewpoints of biological evolution.
(1) Darwinian evolution theory-natural selection theory [content]
Darwin believed that creatures on the earth generally have strong reproductive ability, but due to the limited conditions such as food and living space, creatures will compete for the necessary food and living space in order to survive. After fierce competition for survival, the process of survival of the fittest and elimination of the unfit is natural selection. Biological evolution is the result of natural selection.
Classic examples of natural selection-giraffe and birch moth (knowing that they are the result of natural selection, there is no need to analyze the reasons)
(2) Reasons for biological evolution: heredity and variation are the basis of biological evolution, and environmental change is the external driving force of biological evolution.
Nine, live a healthy life
(1) Etiology, transmission routes and preventive measures of infectious diseases
1. Common infectious diseases and their causes: Infectious diseases refer to diseases caused by pathogens and can be transmitted between people or between people and animals. Common diseases are influenza, tuberculosis, ascariasis, AIDS, atypical pneumonia and trachoma.
2. Transmission route of infectious diseases: The transmission route is the way for pathogens to reach healthy people after leaving the source of infection. Such as air, water drops, water, food, contact, etc. Three basic links in the epidemic of infectious diseases: the source of infection, the route of transmission and the susceptible population.
Note: distinguish between pathogens and sources of infection (people or animals carrying pathogens).
3. Basic measures to prevent the epidemic of infectious diseases: control the source of infection, cut off the route of transmission and protect the susceptible population.
4. Common cardiovascular diseases and preventive measures: Common cardiovascular diseases include coronary heart disease, arteriosclerosis and hypertension. Developing healthy living habits is an effective measure to prevent and treat cardiovascular diseases.
5, common cancer and the main measures to prevent cancer
Common cancers include gastric cancer, liver cancer, lung cancer, esophageal cancer, breast cancer, intestinal cancer and leukemia. In life, we should eliminate or reduce the carcinogenic factors in the environment, and avoid or minimize contact with carcinogenic factors.
(B) the human immune function
Immune defense is called merit.
The first line of defense, skin and mucosa, prevents pathogens from invading and secretes bactericidal substances.
The second line of defense bactericidal substances and phagocytes dissolve, kill and devour pathogens that invade the human body.
The third line of defense is that immune organs and immune cells produce antibodies; Identify and devour pathogens
(3) The difference between specific immunity and nonspecific immunity.
The first and second lines of defense are innate. They are not aimed at a specific pathogen, but have a defensive effect on a variety of pathogens, which is called nonspecific immunity. The third line of defense is acquired and usually only works on specific pathogens or foreign bodies, which is called specific immunity.
(4) The significance of planned immunization:
Planned immunization can improve the human body's resistance to infectious diseases and is the most economical and effective measure to prevent, control and eliminate infectious diseases.
(five) the harm of drinking and smoking to human health:
1, Harm of alcoholism to human health: Alcoholism will make people's central nervous system excessively excited or paralyzed, causing alcoholism.
2. Harm of smoking to human health: Long-term heavy smoking can cause bronchitis, bronchitis, lung cancer and other diseases. Smoking can also cause different degrees of damage to people's circulatory system, digestive system and nervous system, which is easy to cause diseases such as hypertension and coronary heart disease.
3. Develop good living habits: Teenagers are in the period of growth and development, and should consciously develop good personal hygiene habits of not drinking or smoking.
(6) Refuse drugs
1, Common Drugs and Their Harm: Drugs mainly refer to opium, heroin, ice, morphine, cocaine, etc. Drug abuse will reduce people's immunity, seriously damage the brain, affect the regulatory function of the central nervous system, affect cardiovascular and respiratory systems and physiological functions, and also affect normal reproductive capacity. Injecting drugs may also infect hepatitis B and AIDS.
2. Cherish life and refuse drugs: Teenagers should actively publicize the dangers of drugs, consciously fight against illegal activities such as drug abuse and drug trafficking, cherish life, stay away from drugs and refuse drugs for life.
(7) Safe medication:
Carefully analyze all kinds of information on drug labels or instructions before taking medicine.
1. Names and functions of commonly used drugs in family medicine boxes
Commonly used drugs for external use include alcohol, mercuric chloride, iodine, band-aid, eye drops, etc. Commonly used oral drugs are aspirin, Radix Isatidis, Yunnan Baiyao, Chengyunning, Berberine, etc. It is mainly used to treat headache, mild cold, traumatic injury, nausea, vomiting, diarrhea and other diseases.
2. New concept of health: Health includes physical health, mental health, good social adaptation and moral health. Physical health is one of the important signs of a person's health.