"Sexual and asexual reproduction. Formation of sex cells"
To use the preview of presentations, create a Google account (account) and sign in: https://accounts.google.com
Slides captions:
Reproduction is the reproduction of their own kind. Asexual reproduction was performed by Biology teacher Radko O.V.
Reproduction is the ability to produce a new generation of individuals of the same species. Reproduction Sexual Asexual The process of reproduction of organisms in which only one of the parents participates The process in which a new organism develops as a result of the fusion of two germ cells formed by different parents.
Advantages and disadvantages of asexual reproduction Advantages: simple, no need to waste time and energy to find a partner; the number of organisms increases relatively quickly; under unchanging environmental conditions, unlimited possibilities are created for increasing the number of organisms with similar heredity - organisms well adapted to life in these specific conditions. Disadvantage: Does not ensure survival in a changeable, unstable environment (new traits that can be useful in changing environmental conditions appear only as a result of relatively rare situations in asexual reproduction)
Characteristics of asexual reproduction One parent participates Passes without the participation of germ cells A large number of genetically identical organisms are reproduced, rapid settlement and the capture of new territories occur The genotype of the offspring does not differ from the genotypes of both parents
Forms of asexual reproduction Spore formation Budding Cell division Fragmentation Vegetative propagation of plants
Bacterial cell division Cell division Division is the most simple form asexual reproduction, widespread in bacteria and protozoa (single-celled animals and plants).
1 2 3 Mitosis 5 4
Mushrooms Mosses Ferns Sporulation
Budding is one of the forms of asexual reproduction, in which a new individual is formed in the form of an outgrowth (bud) on the body of the parent individual, and then turns into an independent organism Hydra kolanchoe
Fragmentation is the division of individuals into two or more parts, each of which grows and forms a new individual. Reproduction by fragments is typical for sponges, coelenterates (hydra), flatworms (planaria), echinoderms (starfish) and some other species. planaria starfish
Propagation by above-ground parts Leaf cuttings (begonia, saintpaulia, sansevier) stem cuttings(currant, poplar, willow) Creeping shoots (meadow tea, cranberry, tenacious) Layering (currant, gooseberry, raspberry, apple tree) Grafting (apple, pear, plum, cherry)
Propagation by underground parts Root cuttings (rose hip, raspberry, dandelion) Root offspring (aspen, mountain ash, poplar, thistle) Rhizomes (iris, lily of the valley, wheatgrass) Tubers (potatoes, Jerusalem artichoke) Bulbs (daffodil, garlic, tulip)
In most unicellular and multicellular organisms, asexual reproduction can alternate with sexual reproduction, which allows them to optimally solve the problem of reproducing their own kind in various conditions a habitat. For example, in some marine coelenterates, the sexual generation is represented by single free-swimming jellyfish, and the asexual generation is represented by sessile polyps. In plants, such as mosses, the sexual generation (gametophyte) is represented by a leafy plant, and the asexual generation (sporophyte) is a box in which spores develop.
The biological role of asexual reproduction Asexual reproduction - allows you to keep the properties of the species unchanged. This is the important biological significance of this type of reproduction. Organisms that appeared asexually usually develop much faster than those that appeared through sexual reproduction. They quickly increase their numbers and much faster carry out resettlement over large areas.
Fill in the table: Methods of vegetative propagation of plants in nature Methods of vegetative propagation Examples of plants Modified shoots: Rhizomes Bulbs Corms Tubers Stem shoots Root Modified aboveground shoots - mustaches Cuttings: Stem Root leaf Layers Root offspring
Test 1. Reproduction is a process: Increasing the number of cells Development of an organism in the process of evolution Changing an individual from birth to death Reproduction of their own kind 2. Reproduction by spores - a variety of: Vegetative reproduction Simple division Asexual reproduction Sexual reproduction 3. Vegetative reproduction is the process of formation of: A new organism from a part of the mother Specialized cells A unicellular formation with a dense shell of a Multicellular organism 4. Budding is the process of formation of: A vegetative organ A generative organ of a New organism from a part of the mother A new individual in the form of an outgrowth on the body of the mother 5. Asexual reproduction is a process occurring: With the formation of spores With the formation of germ cells With the formation of a zygote Without the formation of germ cells 6. Asexual reproduction: does not affect the ability to adapt to relatively constant conditions environment Reduces the ability to adapt to relatively constant environmental conditions Increases the ability to adapt to relatively constant environmental conditions Increases the ability to adapt to changing environmental conditions. 7. The development of a new individual from somatic cells is called __ _________________________________
Types of reproduction of living organisms
Topic: "Cell", biology, grade 10
Dictionary
reproduction - this is the ability of living organisms to reproduce their own kind, ensuring the continuity and continuity of life in a number of generations.
- reproduction of their own kind;
- An increase in the number of species;
- Transfer of hereditary information from generation to generation.
Methods of reproduction of organisms
reproduction
sexual
asexual
mitosis
meiosis
child
child
parent
parent
Methods of asexual reproduction
asexual
reproduction
Vegetative
budding
reproduction
reproduction
Division
sporulation
schizogony
cells
plots
body
Forms of asexual reproduction
1. Crushing
coli
Organisms: bacteria and blue-green algae
Binary division
This division, in which two equivalent daughter cells are formed
Forms of asexual reproduction
2. Binary division
amoeba
Organisms: unicellular eukaryotes (plants, animals, fungi)
multiple division, or schizogony .
schizogony (from the Greek schizo - I divide, split and ... gony) is a form of asexual reproduction, when the mother cell breaks up into a large number of more or less identical daughter cells (malarial plasmodium). The organism becomes multinucleated and breaks up into many (according to the number of nuclei) single-nuclear cells - merozoites.
3. Multiple division = schizogony
Forms of asexual reproduction
malarial plasmodium
organisms : sporozoan type
sporulation (sporulation)
- With the help of spores (haploid cells with a protective shell). Spores can remain dormant for a long time.
- In this form, they are able to wait out the cold, heat, drying, excess moisture.
Forms of asexual reproduction
4. Sporulation (sporulation)
fern
mushroom spores
flywheel
tubules on the hat mushroom
Organisms: mushrooms
Organisms: spore plants (algae, bryophytes, ferns )
budding
A new individual is formed in the form of an outgrowth (kidney) on the body of the parent, and then separates from it, turning into an independent organism.
Forms of asexual reproduction
5. Budding
fungus yeast
hydra freshwater
Organisms: type coelenterates
Vegetative reproduction
- One of the forms of asexual reproduction, which consists in the formation of a new organism from part of the mother
- Reproduction by body parts (cuttings (stem, root, leaf), modified shoots (rhizome, tubers, bulbs), buds)
- Characteristic of higher plants, an example is budding in sponges and coelenterates
Fragmentation
This is the division of an individual into two or more parts, each of which develops into a new individual.
Fragmentation is based on the property of regeneration.
Forms of asexual reproduction
6. Fragmentation
earthworm
spirogyra
Organisms: type of annelids
Organisms: filamentous green algae
Forms of asexual reproduction
8. Polyembryony
zygote
divided zygote
embryos in one ovum
identical twins
organisms : type chordates
Cloning
This artificial way asexual reproduction. Does not occur in natural conditions.
Clone - genetically identical offspring obtained from one individual as a result of one or another method of asexual reproduction .
Forms of asexual reproduction
9. Cloning
Dolly the sheep and her creator
Professor Ian Wilmut, 1997
All organisms
sexual reproduction
hermaphroditism
dichotomy
parthenogenesis neoteny
lizards
daphnia
aphid
lizards
bees
shellfish
flatworms
guppies
lions
swans
rhinoceros beetles
Axolotl - larva of tiger ambistoma
Hermaphroditism
This is the most primitive form of reproduction, characteristic of many lower animals.
Hermaphroditism makes it possible self-fertilization, which is essential, first of all, for sedentary species or individuals leading a solitary existence. On the other hand, self-fertilization prevents the exchange of genetic material between individuals; many organisms have devices that prevent self-fertilization (genetic incompatibility of germ cells from one organism, the formation of male and female gametes at different times).
- True hermaphroditism - sex products mature in one individual at the same time, and are capable of self-fertilization (bull tapeworm).
- Hermaphroditism, when sexual products mature at different times, more often, individuals fertilize each other, i.e. in one period of life 1 individual is a female, and in another period - a male (earthworms, oysters).
- Hermaphrodites who change sex with age ( fish - parrots live in coral reefs at the beginning of life they are all females, in the 2nd half of life they are males)
Parthenogenesis
Parthenogenesis (from the Greek parthenos - virgin and ... genesis) (virgin reproduction), a form of sexual reproduction, the development of an egg without fertilization. It is characteristic of many invertebrates (daphnia, rotifers, aphids, bees, etc.) and many seed and spore plants. The daughter organism is an exact copy of the parent. Parthenogenesis can be natural and artificial (you can act on unfertilized eggs with acid, shaking, pricking a thin needle, changing the concentration of salts in water – frogs, starfish, silkworms).
- Gynogenesis(from the Greek gyne - woman and ... genesis), a method of development of the egg and the formation of the embryo, in which, after the penetration of the sperm into it, their nuclei do not merge and only the nucleus of the egg is involved in development (silver carp, some newts).
- Androgenesis(from the Greek aner, genus p. andros - a man and ... genesis), "male parthenogenesis", the development of an egg (after penetration of a spermatozoon into it) only with a male nucleus. It is usually observed in the case of the death of the female nucleus before fertilization. (silkworm)
- Pedogenesis(from the Greek pais, genus n. paidos - child and ... genesis) (children's reproduction), a form of parthenogenesis in which unfertilized eggs, giving rise to a new generation, develop in the body of the larvae. Known in a number of invertebrates (some flies, marine crustaceans).
Proper sexual
Actually sexual reproduction is a form of reproduction of dioecious organisms.
Forms of proper sexual reproduction
oogamy - the fusion of the egg and sperm (multicellular animals, some fungi, algae, higher plants)
Heterogamy - fusion of two motile cells with flagella of various sizes (chytrid fungi, algae )
Isogamy - fusion of two-motile gametes of the same size
Stages of sexual reproduction I
Sexual reproduction is characteristic of the vast majority of living beings. It consists of 4 main processes:
1. Gametogenesis - the formation of sex cells (gametes).
2. Fertilization - the fusion of gametes and the formation of a zygote.
3. Embryogenesis - crushing of the zygote and the formation of the embryo.
4. Post-embryonic period - growth and development of the organism in the post-embryonic period.
Features of sexual and asexual reproduction
asexual reproduction
sexual reproduction
Only one individual takes part
Two people take part
Daughter organisms are exact copies of the parent organism
The daughter organism receives a combination of genes belonging to both parents and is not an exact copy of them.
Gametes are not formed.
Gametes are formed with a single (haploid) set of chromosomes, the nuclei of which merge (fertilization), a zygote is formed that carries the chromosomes of both parents.
It occurs in microorganisms, fungi, plants and some invertebrates.
Common to most plants and animals.
Leads to a rapid increase in the number of individuals.
It happens more slowly, but individuals better adapt to changing environmental conditions.
slide 1
BREEDING FORMS
slide 2
Lesson objectives
Educational: to introduce students to the phenomenon of reproduction, a variety of methods of reproduction. Developing: to develop the ability to work with drawings, tables, diagrams, comparing and analyzing. Educational: using already known, as well as received information, to prevent misinterpretations of the issue of reproduction.
slide 3
forms of reproduction.
Asexual. Cell division. Budding. Vegetative. Sporulation.
Sexual. Hermaphroditism. Parthenogenesis.
slide 4
Features of sexual and asexual reproduction
asexual reproduction sexual reproduction
Only one individual takes part Two individuals take part
Daughter organisms are exact copies of the parent organism The daughter organism receives a combination of genes belonging to both parents and is not an exact copy of them
Gametes are not formed. Gametes are formed with a single (haploid) set of chromosomes, the nuclei of which merge (fertilization), a zygote is formed that carries the chromosomes of both parents.
It occurs in microorganisms, fungi, plants and some invertebrates. Common to most plants and animals.
Leads to a rapid increase in the number of individuals. It happens more slowly, but individuals better adapt to changing environmental conditions.
slide 5
Methods of asexual reproduction
slide 6
Cell division of the trypanosome flagellate.
division of protozoa
cell division
amoeba division
Slide 7
Initially, a small tubercle is formed on the mother cell - a kidney. It grows, increases in size. The nucleus of the mother cell divides. Then one of the formed daughter nuclei moves to the kidney. A new cell is formed. She may continue to live with her mother or separate.
budding
In summer, clusters of dividing cells - kidneys - form on the surface of the hydra's body, gradually they increase, they have tentacles and a mouth opening.
Slide 8
A spore is a special type of cell with very dense membranes. Spores can remain dormant for a long time. In this form, they are able to wait out the cold, heat, drying, excess moisture. When favorable conditions come, they germinate, divide, and new individuals are formed from them.
Slide 9
vegetative reproduction.
Root
The escape
Sheet
Shanks Mustaches Bulbs
TO
Slide 10
Vegetative.
tubers
cuttings
Mustache
slide 11
Sexual reproduction.
During sexual reproduction, animals produce sex cells - gametes. Each gamete contains half as many chromosomes as the others.
slide 12
slide 13
Hermaphroditism.
Examples of hermaphroditism: flatworms - white planaria; Tapeworms - bovine tapeworm; Mollusks are a big pond snail.
Hermaphroditism is a phenomenon in which the same individual is able to produce both male and female cells.
To use the preview of presentations, create a Google account (account) and sign in: https://accounts.google.com
Slides captions:
sexual reproduction
Reproduction A universal property of living organisms The ability to produce similar individuals of their own species
Sexual reproduction Differs in the presence of a sexual process Occurs with the participation of haploid germ cells - gametes Gametes are formed in special organs of male and female individuals The genetic material of the parent individuals combines, resulting in an increase genetic diversity offspring and its vitality
Types of the sexual process The body acquires new features, but the number of individuals does not increase Conjugation - the exchange of parts of genetic material Copulation - unicellular organisms turn into gametes indistinguishable from each other and merge Ciliates, Polytoma spirogyra, chlamydomonas
Types of the sexual process Heterogamy - the fusion of two mobile cells of different sizes Oogamy - the fusion of a large, immobile egg and a small, mobile spermatozoon Isogamy - the fusion of two-motile gametes of the same size Parthenogenesis - development from an unfertilized egg
Reproductive Organs Gametangia - algae, fungi Plants Animals Antheridia Archegonia Sex glands Testes Ovaries
Biological species depending on the cells produced Dioecious females, males Bisexual hermaphrodites
Human germ cells acrosome The width of the human spermatozoon is about 0.005 mm, the length is 0.06-0.07 mm, and the mass is 0.000000005 g. 1 cm3 of sperm contains from 20 to 60 million spermatozoa.
Human germ cells
bird sex cells
The structure of germ cells Signs Female gametes Male gametes Shapes and sizes Structural features Number of chromosomes Main functions
Gametogenesis spermatogenesis ovogenesis Reproductive phase Growth phase Maturation phase Guiding bodies 2 n Formation phase 2 n 2 n 2 n 2 n 2 n 2 n 2 n n n n n n n n n n n n 2 n n n n n n
Hermaphrodites Bisexual animals The advantage of bisexuality is the possibility of self-fertilization In the presence of a sexual partner, cross-fertilization is observed
On the topic: methodological developments, presentations and notes
Lesson development for 6th grade. Presented work in groups. During the lesson, all students in the class answer at the blackboard ....
Description of the presentation on individual slides:
1 slide
Description of the slide:
Presentation on the topic: “Asexual and sexual reproduction and their types” Prepared by: Vorkozhokov Ilyas Checked by: Tretyak Yana Dmitrievna
2 slide
Description of the slide:
Reproduction is the ability of organisms to produce similar individuals of the same species. This function is inherent in all living beings. Reproduction is aimed at preserving genes in the offspring and procreation - thereby preserving the gene pool of a population, species, family, etc. All the variety of methods of reproduction can be divided into two main types: asexual reproduction and sexual reproduction.
3 slide
Description of the slide:
Asexual reproduction is a form of reproduction in which an organism reproduces itself without any involvement of another individual. It occurs without the formation of special cells, while identical descendants are formed. The only source of genetic variation is random mutations. The cytological basis of asexual reproduction is mitosis. The molecular basis of asexual reproduction is DNA replication. Asexual reproduction in different living organisms can occur in different ways.
4 slide
Description of the slide:
Forms of asexual reproduction: Division is characteristic of unicellular organisms. It is carried out by simple cell division in two. In all cases, the resulting cells are completely identical to the original. An organism is capable of endlessly reproducing itself until a spontaneous change in the genetic material (mutation) occurs.
5 slide
Description of the slide:
Shizogony - multiple asexual reproduction in protozoa and some algae. In schizogony, the nucleus of the maternal individual, or schizoite, is divided by rapidly successive divisions into several nuclei, after which the entire schizont breaks up into the corresponding number of mononuclear cells (merozoites). After several asexual generations, the sexual process begins.
6 slide
Description of the slide:
Budding is carried out by the formation of a kidney on the mother's body - an outgrowth from which a new individual develops. In animals, budding is external and internal. In a number of animals, budding does not reach the end; young individuals remain connected to the mother's organism; as a result, colonies consisting of many individuals appear. Sometimes Budding can be caused artificially by various effects on the mother's body, such as burns or cuts.
7 slide
Description of the slide:
Sporulation Reproduction by spore formation is associated with the occurrence of spores. This form of reproduction is common in algae, fungi, mosses, and ferns. In algae, some cells can form spores (zoospores). Do more highly organized plants spores are produced in sporangia
8 slide
Description of the slide:
Fragmentation is the division of an individual into several parts, each of which forms a new individual. Fragmentation occurs, for example, in filamentous algae such as spirogyra. Fragmentation is also observed in some lower animals, which, in contrast to more highly organized forms, retain a significant ability to regenerate from relatively poorly differentiated cells.
9 slide
Description of the slide:
Sexual reproduction is the process by which genetic information from two individuals is combined. During sexual reproduction, individuals of different sexes form gametes. Females produce eggs, males produce sperm. Thus, during sexual reproduction, the genomes of two different individuals of the same species are mixed. Offspring carry new genetic combinations that distinguish them from their parents and from each other.
10 slide
Description of the slide:
The formation of gametes The basis for the formation of gametes (gametogenesis) is meiosis - cell division with a halving of the number of chromosomes, as a result of which gametes, unlike all other cells of the body, are haploid. Recombination - redistribution of the genetic material of parents in the offspring, leading to hereditary combinative variability of living organisms.
11 slide
Description of the slide:
Types of sexual reproduction CONJUGATION - a form of the sexual process in which the contents of two outwardly similar flagellar cells merge; sexual process, which consists in the temporary connection of two individuals and the exchange of parts of their nuclear apparatus, as well as a small amount of cytoplasm. ciliate conjugation
12 slide
Description of the slide:
GAMETIC COPULATION - the connection of sexual elements, which are single-nuclear independent gametes, each of which can be mobile or immobile. Copulation occurs only between male (microgametes) and female (macrogametes) germ cells of animals, where meiosis precedes the formation of gametes (gametic reduction) and all cells of the body, except for mature germ cells, are diploid. Further, such an individual reproduces by division.
13 slide
Description of the slide:
Anisogamy is a form of the sexual process in which two morphologically different (in shape) gametes merge. In anisogamy, gametes are divided into male and female and have different type mating The term "anisogamy" is usually used only in relation to plants and protozoa, although in multicellular animals the sexual process sometimes proceeds in the form of anisogamy.
14 slide
Description of the slide:
Isogamy is a primitive form of the sexual process, in which two identical morphologically and in size gametes merge. It is characteristic of equal flagellate green algae and chytrid fungi. With isogamy, gametes are not divided into male and female. At fertilization, two gametes various types matings fuse to form a zygote. Ovogamy (Oogamy) - a type of sexual process in which during fertilization merge, forming a zygote, sharply different in size, shape and behavior of germ cells - Gametes. Female gamete - Ovum - large, immobile, without flagella. Male - much smaller, usually mobile (has one or more flagella and is called Spermatozoon, less often - flagellaless, for example, spermatozoa in some lower plants, spermatozoa in many gymnosperms and all angiosperms). It is characteristic of all multicellular animals, many lower and all higher plants.
15 slide
Description of the slide:
Parthenogenesis Parthenogenesis is the so-called "virgin reproduction", one of the forms of sexual reproduction of organisms, in which female germ cells (eggs) develop into an adult organism without fertilization. Although parthenogenetic reproduction does not involve the fusion of male and female gametes, parthenogenesis is still considered sexual reproduction, since the organism develops from a germ cell. It is believed that parthenogenesis arose in the process of evolution of organisms in dioecious forms.
16 slide
Description of the slide:
