Section 65438 Mendel pea hybridization experiment +0 and 2
First, the basic concept:
(1) Character-It is the morphological, structural, physiological and biochemical characteristics of an organism.
(2) Relative traits-different types of expression of the same trait of the same organism.
(3) In the parents' cross experiment with relative traits, the traits shown in the first hybrid generation (F 1) are dominant, while those not shown are recessive.
(4) Character segregation refers to the phenomenon that both dominant and recessive characters appear in hybrid offspring.
(5) Hybridization-mating or pollination between parents with different relative traits.
(6) Self-pollination-mating or pollination between individuals with the same genotype (self-pollination is one of them)
(7) Test crossing —— A crossing method in which individuals with recessive traits (homozygotes) are mated or pollinated with individuals with unknown genotypes to determine the type and proportion (genotype) of gametes that the unknown individuals can produce.
(8) Phenotype-the characteristics displayed by biological individuals.
(9) Genotype-gene composition related to phenotype.
(10) allele-a gene located at the same position of a pair of homologous chromosomes and controlling related traits.
Non-allelic genes-including genes on non-homologous chromosomes and genes in different positions on homologous chromosomes.
(1 1) gene-DNA fragment with genetic effect, arranged linearly on chromosome.
Second, the reason for the success of Mendel's experiment:
(1) Correct selection of experimental materials: One pea is a strictly self-pollinated plant (closed pollination), which is generally pure in nature, and two peas are easy to distinguish.
(2) The research from one pair of related words to many pairs of related words.
(3) Analysis method: Statistical method was used to analyze the results.
(4) Experimental steps: Hypothetical deduction method.
Observation and analysis-hypothesis-deductive reasoning-experimental verification
Third, Mendel pea hybridization experiment
(a) The hybridization of a pair of related characters:
P: tall pea× short pea P: AA× AA
↓ ↓
F 1: high pea F 1: AA
selfing
F2: tall pea and short pea F2: aaaaaa
3 : 1 1 :2 : 1
(2) Crossing of two pairs of related traits:
P: yellow circle × green wrinkle P: AABB × AABB
↓ ↓
F 1: yellow circle F 1: AABB
selfing
F2: yellow circle, yellow wrinkle, green circle and green wrinkle F2: A-B-A-BBAAB-AABB.
9 :3 : 3 : 1 9 :3 : 3 : 1
In F2 generation:
Four phenotypes: two parental types: yellow circle 9/ 16 green wrinkle116.
Two recombinant forms: yellow wrinkle 3/ 16 and green wrinkle 3/ 16.
Nine genotypes: completely homozygous AABBAABBAABBAABBAABBAABBAABBAABBAABBA * * 4 species ×116.
Semi-homozygous hemizygote AABBAABBAABBAABBAABBA * * 4 species× 2/16
Complete heterozygote AaBb *** 1 species× 4/16.
Fourth, basic exercises
1. If tall stalk (d) is dominant for short stalk (d), rice blast resistance (r) is dominant for susceptible rice blast (r), and two pairs of traits are independently inherited. At present, a homozygous dwarf variety susceptible to rice blast (lodging resistance) is crossed with a homozygous tall variety resistant to rice blast (lodging resistance), and the ratio of lodging resistance and disease resistance types in F2 is: ()
a、 1 / 8 B、 1 / 16 C、3 / 16 D、3 / 8
2. The genotype of AaBb hybridizes with AABB, and the phenotypic ratio of F 1 is: ()
a、9:3:3: 1 B、 1: 1: 1 C、3: 1:3: 1 D、3: 1
3. In pumpkin fruit, white (w) is dominant to yellow (w), and discoid (d) is dominant to (d), and two pairs of genes are inherited independently. Among the offspring produced by the following different parent combinations, the group with the most white spherical fruits is: ()
a、WwDd×wwdd B、WwDd×wwdd
c、WwDd×wwDD D、WwDd×wwDD
4. A pair of heterozygous black guinea pigs gave birth to four offspring, and the phenotype of the four offspring may be: ()
A, three black and one white B, all black C, three black and one white D, all three are possible.
5. When two parents hybridize, the gene inheritance follows the law of free combination, and their offspring genotypes are: 1YRR, 2YRR, 1YRR, 1YRR, 2YRR, 1YRR, so the genotypes of these two parents are ().
A, YYRr and YYRr B, YYrr and YYRR
C, YyRr and YyRr D, YyRr and YYRr
Chapter II Relationship between Genes and Chromosomes
Part I: Meiosis and Fertilization:
First, the basic concept:
1, meiosis-
2, fertilization-
Second, the formation of sexual germ cells:
1, location: testis and ovary of animals; Anthers and ovules of plants
2. Spermatogenesis: 3. Egg cell formation.
1 spermatogonia (2n)
Interval: chromosome replication interval: chromosome replication
1 primary spermatocyte (2n) 1 primary oocyte (2n)
The prophase: synapse, tetrad and cross exchange (2n) ↓ The prophase: synapse, tetrad ... (2n)
Metaphase: Homologous chromosomes are arranged on the equatorial plate (2n) Metaphase: (2n)
Late stage: paired homologous chromosome segregation (2n) Late stage: (2n)
Terminal stage: the terminal stage of isocytoplasmic division: isocytoplasmic division (2n)
2 secondary spermatocyte (n) 1 secondary oocyte+1 polar body (n)
↓ prophase: (n) ↓ prophase: (n)
Mid-term: (n) Mid-term: (n)
Late stage: chromatids are divided into two groups of chromosomes (2n).
End stage: Isoplasmic separation (n) End stage: (n)
Four sperm cells: (n) 1 egg cell: (n)+3 polar bodies (n)
deformed
Four sperm
4. Comparison between spermatogenesis and oocyte formation:
Spermatogenesis, egg formation
Minister position
Number of daughter cells
Do cells divide evenly?
Is there a deformation period?
Third, fertilization and its significance:
1, fertilization-
2. The meaning of fertilization:
The diversity of gametes formed by meiosis and the randomness of sperm-egg combination lead to the diversity of offspring traits.
Meiosis and fertilization are of great significance for maintaining the constant number of chromosomes in biological cells.
Four, the identification of cell division period:
1, whether the cytoplasm is equally divided: unequal division-the formation of meiotic eggs.
Equal division-mitosis and meiosis sperm formation
2. The number of chromosomes in the cell: if it is odd-the dichotomy of meiosis (secondary spermatocyte, secondary oocyte).
If it is even-mitosis, the first meiosis, the late binary fission stage of meiosis.
3. Chromosome behavior in cells: synapse and tetrad phenomenon-prophase of meiosis (tetrad stage).
There are homologous chromosomes-mitosis and meiosis.
Non-homologous chromosome-meiotic dichotomy
Isolation of Homologous Chromosomes —— Late Stage of the First Meiosis
There is a homologous chromosome on the separation side of sister chromatids-the late binary fission stage of meiosis.
No homologous chromosome on one side-late mitosis
Section 2, Genes on Chromosomes
1. Sutton hypothesis: genes are carried by chromosomes and passed from parents to the next generation. That is, the gene is on the chromosome.
Research methods: analogical reasoning-
Second, the experimental evidence of genes on chromosomes:
Morgan blink experiment of Drosophila: (A- red eye gene A- white eye gene X, Y- Drosophila sex chromosome)
P: red eye (female) × white eye (male) P: xaxa× xay
↓ ↓
F 1: red eye F 1: xaxa× xay
↓F 1 male and female mating ↓
F2: red eyes (male and female) and white eyes (male) F2: xaxaxaxaxaxay xay.
The third section, sex-linked inheritance
Concept: Sex-linked inheritance-The genetic control genes of such traits are located on sex chromosomes, so they are always associated with sex.
Type: X chromosome dominant inheritance: anti-vitamin D rickets, etc.
X chromosome recessive inheritance: human red-green color blindness and hemophilia
Y chromosome inheritance: human hair ear phenomenon
First, the recessive inheritance of X chromosome: such as human red-green color blindness
1. Pathogenic gene Xa Normal gene: XA
2. Patient: male XaY, female xax.
Normal: male XAY female XAXA (carrier)
3. Genetic characteristics:
(1) The number of patients in the population is larger than that of women.
(2) atavism.
(3) Cross-genetic phenomenon: male → female → male.
Second, the dominant inheritance of X chromosome: such as vitamin D-resistant rickets
1. Pathogenic gene Xa Normal gene: XA
2. Patient: male XAY, female XAXA XAXa.
Normal: male XaY female xax
3. Genetic characteristics:
(1) The population has more cases than men.
(2) continuous genetic phenomenon
(3) Cross-genetic phenomenon: male → female → male.
Third, Y chromosome inheritance: human hair ear phenomenon
Genetic characteristics: The gene is located on the Y chromosome and is only inherited in male individuals.
Fourth, gender type:
XY type: XX female XY male-most higher organisms: humans, animals and higher plants.
XW type: ZZ male and ZW female-birds, silkworms, moths and butterflies.
Verb (abbreviation of verb) identification of genetic diseases;
(1) First, judge the dominant and recessive inheritance:
Parents are not sick, children are sick-recessive inheritance (out of thin air)
Atavism-recessive inheritance
Parents are sick, children are not sick-dominant inheritance (some are out of thin air)
Successive inheritance, generational inheritance-dominant inheritance
(2) Re-judging the inheritance of autosomal and sex chromosomes;
1, parents are not sick, and daughters are sick-common and recessive inheritance.
2. Known recessive inheritance, the mother's sick son is normal-normal and recessive inheritance.
3, known dominant inheritance, father is sick, daughter is normal-normal and dominant inheritance.
4、
(3) After the judgment in (1) is completed, it is inferred by the hypothesis method.
Basic exercises:
The cell shown in Figure 6 is a stage of meiosis.
The cells shown in (1) are in the _ _ _ _ _ _ _ _ phase of meiosis.
(2) There are _ _ _ _ _ pairs of homologous chromosomes in the cell.
They are _ _ _ _ _ _.
(3) There are _ _ _ _ _ _ _ chromosomes in the cell.
They are _ _ _ _ _ _ _.
(4) There are _ _ _ _ _ _ _ chromatids in cells.
They are _ _ _ _ _ _ _ _ _ _ _ _ _ _ _.
chapter three
Section 1 DNA is the main genetic material
Knowledge point: 1. How to prove that DNA is genetic material (pneumococcal transformation experiment, Avery experiment, T2 phage infection experiment of Escherichia coli).
2. What are the conditions for 2.DNA as genetic material?
3. The experimental process of 3.T2 phage infecting Escherichia coli: adsorption, injection, synthesis, assembly and release.
Exercise:
1. Chromosome is the genetic material of an organism, and DNA is also the genetic material of an organism. ( × )
2. The genetic material in eukaryotic cells is DNA, and the genetic material in viruses is DNA. ( × )
3. In prokaryotes, DNA is located in pseudonucleus.
4.hershey and Chase's experiment of T2 phage infecting Escherichia coli showed that: (d)
A, there is DNA in the virus, but there is no protein. B, there is DNA in the bacteria, but there is no protein.
C. The genetic material includes protein and DNA D, and the genetic material is DNA.
5. The characteristics of DNA as genetic material were analyzed by combining pneumococcal transformation experiment and phage infection experiment.
Answer: 1, which can accurately copy itself.
2. It can guide the synthesis of protein, thus controlling biological characteristics and metabolism.
3. It has the ability to store genetic material; 4. Its structure is relatively stable.
6. The genetic material of most organisms is nucleic acid, and DNA is the main genetic material.
7.DNA molecules are biological macromolecules polymerized from many deoxynucleotides. Deoxynucleotide consists of phosphoric acid, pentose and base. Because there are four bases, there are four deoxynucleotides.
8. In order to prove that the DNA of S-type bacteria is genetic material but protein is not, scientists separated the DNA of S-type bacteria from protein in the experiment to obtain pure DNA and protein, and then added them to the culture medium of R-type bacteria respectively to observe their transformation.
Section 2 the structure of DNA molecules
Knowledge point: What are the main features of the double helix structure of DNA molecules?
1, DNA consists of two strands, which spiral into a double helix structure in an anti-parallel manner.
2. deoxyribose and phosphoric acid in 2.DNA molecules are alternately connected and arranged on the outside to form the basic skeleton; The base is inside.
3. The bases on the two chains are connected into base pairs by hydrogen bonds, and the base pairing has certain rules: A (adenine) must be paired with T (thymine); G (guanine) must be paired with c (cytosine). This one-to-one correspondence between bases is called the principle of base complementary pairing.
Exercise:
1 On the right is the structural pattern diagram of DNA molecules. Please write the names in the chart in words. 、
1、 2、
3、 4、
5、 6、
7、 8、
9、 10、
2. It is known that 1 DNA molecule has 4000 base pairs, including 2200 cytosine. The number of deoxynucleotides and adenine in this DNA molecule is: ()
A, 4000 and 900 b, 4000 and 1800.
C, 8000 and 1800 d, 8000 and 3600.
3. The double helix structure model of 3.DNA molecule was put forward by Watson and Crick.
4. There are four bases in 4.DNA molecule, namely,, and, and the bases on the two chains are connected by bonds.
5. The base pairing of 5.DNA is regular, that is, it must be paired and paired. This pairing makes DNA molecules stable, which can explain the relationship among A, T, C and G, and the process of DNA.
Attachment: some mathematical formulas derived from the principle of base complementary pairing;
a = T； g = C；
(A+G)/(T+C)= 1； (A+C)=(T+G)
A+T on one chain is equal to T+A on another chain, and C+G on one chain is equal to G+C on the other chain.
If (A+T)/(C+G)=a on one chain, the ratio on the other chain is also a.
If (A+C)/(G+T)=b in one chain, the ratio in the other chain is1/b.
In addition, the sum of two non-complementary bases accounts for 50% of the total DNA bases.
Section 3 DNA replication
Knowledge points: the process of DNA replication (the concept, conditions, characteristics, results and significance of DNA replication)
The process of DNA molecular replication is a process of melting and replication.
The conditions of DNA replication need related enzymes, raw materials, energy and templates.
Its characteristic is (discontinuous) semi-conservative replication.
Its significance lies in ensuring the similarity between parents and children.
Exercise:
It can be seen from the replication process of DNA molecules that DNA molecules need conditions such as,, and so on. The structure of DNA molecules can provide an accurate template for replication and ensure that replication can be carried out correctly.
The fourth gene is a DNA fragment with genetic effect.
Knowledge point: 1. Definition of gene (gene is a DNA fragment with genetic effect).
2. Conditions for 2.DNA to inherit substances: A, it can replicate itself; B, its structure is relatively stable; C, it can store genetic information; D, traits can be controlled.
3. Characteristics of 3.DNA molecules: diversity, specificity and stability.
Exercise:
1 Generally speaking, a chromosome has 1 DNA molecule, and a DNA molecule has many genes, and each gene consists of many deoxynucleotides.
2. The base sequence in 2.DNA represents genetic information. Different sequences of bases in the DNA of different organisms constitute the diversity of DNA molecules, and the specific sequences of bases in the DNA of the same organism constitute the specificity of DNA molecules.
chapter four
Section 1 Genes Directing protein's Synthesis
Knowledge points:
transfer
Definition: The process of synthesizing mRNA with a DNA as a template in the nucleus.
Unit: cell nucleus
Template: a DNA strand
The direction of information transmission: DNA? ——mRNA
Raw materials: four nucleotides containing a, u, c and g.
Product: messenger RNA
translate
Definition: protein with a certain amino acid sequence was synthesized from various amino acids dissociated in cytoplasm with mRNA as a template. This process is called translation.
Environment: cytoplasm (ribosome)
Conditions: ATP, enzyme, raw material (AA), template (mRNA).
Direction of information transmission: mRNA to protein.
Codon: Three adjacent bases on mRNA determine 1 AA. Every three such bases are also called 1 codon.
MRNA linearity tRNA clover rRNA linearity
Translation site: The binding site of ribosome and mRNA forms two binding sites of tRNA. (tRNA carries the corresponding amino acid into the corresponding site)
Exercise:
If the base sequence of one strand of a DNA molecule is acggatctt, then the base sequence of another DNA strand complementary to it is tgcctagaa. If this DNA strand is used as a template, it is transcribed.
The base sequence of mRNA should be UGCCUAGAA, and there are three codons in this mRAN. Three tRNA are needed to transport the required amino acids to ribosomes. These amino acids are cysteine-leucine-glutamic acid in turn.
The transcription process is
1 DNA double-stranded unwinding
Using a DNA strand as a template, Mrna was synthesized according to the principle of base complementary pairing.
3 The synthesized mRNA is released from the DNA chain.
Gene control of traits in the second quarter
Knowledge points:
Central rule: genetic information can flow from DNA to DNA, that is, DNA replicates itself; It can also flow from DNA to RNA and then to protein, that is, the transcription and translation of genetic information. However, genetic information cannot flow from protein to protein, nor can it flow from protein to DNA or RNA. In recent years, it has also been found that genetic information can also flow from RNA to RNA (that is, self-replication of RNA) and from RNA to DNA (that is, reverse transcription), and a large increase of protein itself (self-controlled replication of protein) has also been found in BSE virus.
The relationship among genes, protein and traits;
1. gene controls the metabolism of biological substances by controlling the synthesis of enzymes, and then controls the characteristics of organisms.
2. Genes can also directly control the traits of organisms by controlling the structure of protein.
Relationship between genotype and phenotype: protein during or after gene expression may also be affected by environmental factors.
Polygenic factors of biological traits: gene gene; Genes and their products; There are complex interactions between various factors and the environment, and * * * finely regulates biological characteristics in the same place.
Cytoplasmic genes: Genes in DNA in mitochondria and chloroplasts are called cytoplasmic genes. Its main feature is maternal inheritance.
Exercise:
1, the "central rule" was first named by Crick, which refers to the general law of genetic information transmission, and its process is as follows:
2. Biological characters are controlled by genes, but also influenced by environmental factors.
Chapter V Gene Mutations and Other Variations
Section 1 Gene Mutation and Gene Recombination
Knowledge points:
1, the cause of sickle anemia
Changes in base pairs of DNA-changes in base pairs of mRNA molecules-changes in ——AA-changes in protein-changes in traits.
2. The concept of gene mutation: the change of gene structure caused by the substitution, addition and deletion of base pairs in DNA molecules is called gene mutation.
3. Causes and characteristics of gene mutation:
Reasons: physical reasons, chemical reasons and biological factors.
Features: A, universality B, randomness C, low frequency D, harmfulness E and directionality.
4. The significance of gene mutation: it is the way to produce new genes; Is the fundamental source of biological variation; It is the original material of biological evolution.
5. The concept of gene recombination: refers to the recombination of genes controlling different characters in the process of biological sexual reproduction.
6. Type: A. Free combination of nonallelic genes on non-homologous chromosomes. B, free combination between alleles on homologous chromosomes
7. Significance of gene recombination: Gene recombination produces new genotypes, which is also one of the sources of biological variation and is also of great significance to the evolution of organisms.
8. Application: Mutation breeding and cross breeding. (For details, see Chapter 6, Section 1)
Exercise:
The way to produce new genes is gene mutation; The fundamental source of biological variation is gene mutation. There are always some differences between parents and offspring of sexually reproductive organisms. The main reason is gene recombination.
Chromosome variation in the second quarter
Knowledge points: structural variation
1, individuals increase or decrease chromosome variation.
Digital change
To multiply or decrease.
2. Genome
(1) Concept: A group of non-homologous chromosomes in a cell, with different shapes and functions, carries all the genetic information that controls biological development. Such a set of chromosomes is called genome. Egg cells (gametes) of female Drosophila melanogaster.
(2) Features: It does not contain homologous chromosomes, but contains one of each pair of homologous chromosomes.
3. Double
(1) Concept: refers to an individual with two chromosomes in somatic cells.
(2) For example: people and rice.
4. Polyploid
(1) Concept: refers to an individual with three or more chromosomes in somatic cells.
(2) Cause: During mitosis, chromosomes replicate, but do not separate.
(3) Features: stout stems, large leaves, fruits and seeds, and rich in organic matter.
(4) Application: artificially induced polyploid breeding (see the first section of Chapter 6 for details).
5. Haploid
(1) Concept: An individual whose somatic cells contain the number of gametes of this species.
(2) Occurrence: It develops from gametes.
(3) Characteristics: Haploid plants are weak and highly sterile.
(4) application: haploid breeding (see section 1 of chapter 6 for details)
Section 3 Human genetic diseases
Knowledge points:
1. Concept: It usually refers to human diseases caused by genetic material changes, which are mainly divided into three categories: monogenic genetic diseases, polygenic genetic diseases and chromosomal abnormal genetic diseases.
Dominant genetic diseases: syndactyly, polydactyly and myotonia.
euchromosome
Single gene recessive genetic diseases: albinism, phenylketonuria, dwarfism.
Advantages of hereditary diseases: resistance to vitamin D rickets.
X
Sex chromosome recessive: red-green color blindness, hemophilia, progressive muscular dystrophy.
Human hair and ear diseases (male patients only)
Infectious polygenic genetic diseases: essential hypertension, coronary heart disease, juvenile diabetes.
Abnormal number
cause
Chromosome heterostructure abnormality
Autogenetic diseases: autosome: 2 1 trisomy syndrome, meow syndrome.
type
Sex chromosome: gonadal dysplasia (such as Turner syndrome)
2. Features:
A, the pathogenic gene comes from parents, so it has shown symptoms or is in a potential state in the fetal period.
B, it is often a lifetime.
C, often familial, appears in a certain proportion among members.
3. Harm:
First, endanger human health
B, endangering future generations
C, increased social burden
4. The human genome project is to determine all the DNA sequences of the human genome and interpret the genetic information contained in them. China, the United States, Germany, Britain, France and Japan participated in this work.
Exercise:
The picture below shows the chromosome map of Drosophila melanogaster. According to the picture, the answer is:
(1) The sex of Drosophila shown in Figure A is Drosophila.
(2) The sex chromosome in Figure A is.
(3) There is a genome in Figure B. ..
If sex chromosome symbols are used instead of chromosome numbers in the figure, the chromosomes of each chromosome group are.
Chapter 6 from cross breeding to genetic engineering
1 node hybrid breeding and induced breeding
Knowledge points: comparison of four kinds of culture
Cross breeding, mutation breeding, polyploid breeding and haploid breeding.
Treating hybridization, treating organisms with physical and chemical factors, treating germinated seeds or seedlings with colchicine, and culturing anthers in vitro.
Principle Through gene recombination, the excellent traits of parents are combined into the same offspring, thus producing a new type that meets the requirements. Artificial methods are used to induce gene mutation, produce new traits and create new varieties or types. Inhibition of spindle formation in cell division, so that two cells cannot be formed after doubling the number of chromosomes. Sperm is induced to grow directly into plants, and then doubled into homozygotes with colchicine.
Advantages and disadvantages The method is simple, easy to operate, unable to create new genes, and the breeding process is slow and complicated. It can increase the frequency of mutation, greatly improve some traits, stabilize mutant traits and speed up the breeding process.
There are few advantages, a large number of experimental materials need to be processed, the direction of mutation is difficult to grasp, and it is difficult for mutants to concentrate multiple ideal traits, with large organs and high nutritional content.
Growth retardation and low seed setting rate. There is no trait segregation in self-bred offspring, which can shorten the breeding cycle (2 years).
The method is complicated and the survival rate is low.
Example High (lodging-resistant) and rust-resistant wheat varieties were crossed with low-stem (lodging-resistant) sensitive varieties to cultivate short-stem rust-resistant wheat varieties. Penicillin was irradiated by X-ray, ultraviolet ray and comprehensive treatment, and a high-yield penicillin strain was cultivated. Breeding of disease-resistant plants of triploid seedless watermelon and octoploid triticale.
Section 2 Genetic Engineering and Its Application
Knowledge points:
1. Concept: According to people's wishes, a gene of one organism is extracted, transformed and transformed, and then put into the cells of another organism to directionally transform the genetic traits of the organism.
2. Tools:
Gene scissors: restriction endonucleases
The "needle and thread" of gene: DNA ligase
Gene "Carrier": Carrier
The basic step of gene manipulation: 1, extracting the target gene. 2. The target gene is combined with the vector (plasmid as the vector). 3. Introduce the target gene into the recipient cell.
Chapter VII Theory of Modern Biological Evolution
The first section, the origin of modern biological evolution theory
First, Lamarck's evolutionary theory: use and discard in acquired inheritance.
Second, Darwin's theory of natural selection:
1, main contents: over-reproduction, survival competition, gene variation, survival of the fittest.
2. Natural selection: the process of survival of the fittest and elimination of the unsuitable in the competition for survival. Natural selection is a slow and long historical process.
3. Significance: The theory of natural selection can scientifically explain the causes of biological evolution and the diversity and adaptability of organisms.
4. Disadvantages: The nature of heredity and variation cannot be explained scientifically. The explanation of biological evolution is limited to the individual level.
The second section, the main content of modern biological evolution theory.
First, changes in population gene frequency and biological evolution.
1, population is the basic unit of biological evolution.
Population—
Population gene bank—
Gene frequency—
2. Mutation and gene recombination produce the raw materials of evolution.
(1) Biological heritable variation comes from gene mutation, gene recombination and chromosome variation. Gene mutation and chromosome variation are collectively referred to as mutation.
(2) Mutation and recombination are random and non-directional, which only provide raw materials for biological evolution and cannot determine the direction of biological evolution.
3. Natural selection determines the direction of biological evolution.
Under the action of natural selection, the gene frequency of the population will change directionally, leading to the continuous evolution of organisms in a certain direction.
Second, isolation and speciation.
1, basic concept:
Isolation—
Species—
Reproductive isolation—
Geographical isolation—
2. The role of isolation in speciation
III. * * * Co-evolution and the Formation of Biodiversity
1, * * * coevolution-between different species, between biological and inorganic environments, continuous evolution and development.
2. Biodiversity-mainly includes three levels: genetic diversity, species diversity and ecosystem diversity.