notes of chapter reproduction in animals class 8
Answers
the process of living organisms producing its offspring is called reproduction based on reproduction animals are classified into two types viviParis and oviparous some animals give birth to young ones have epidermal hair on their skin and external ears these animals do not lay eggs and their called as ViviParis . where are the animals that do not have epidermal hair or external ears and lay eggs are called as oviparous generally all organisms in the world are classified as male and female and reproduce and continue their generation but where as the lower organisms this differentiation is not seen for example Amoeba Paramecium Hydra and these undertake asexual reproduction. the resistance of a sexual reproduction they are fission fission means Unicellular organisms reproduce by splitting into half examples bacteria binary fission means unicellular organisms reproduce by dividing into two halves example Amoeba and trypanosoma MultiplyFission means in a Unicellular organisms like plasmodium reproduce by dividing into more than two house fragmentation means the new individuals are reproduced from the piece of damaged parental body example Spirogyra. spore formation means the spores are developed on sporangium reproduce examples rhizopus and budding means no individuals are developed from the but this type of asexual reproduction is called budding example Hydra yEast. nucleus pressure vital role in Reproduction of amoeba by dividing itself into 2 halves. in plants also sexual reproduction takes place in this process pollen grains produced in the Pollen separate the stigma of a flower where they germinate a long tube is formed from the pollen grains that reaches the ovary the male reproductive cell of the Pollen Grain travels down the tube to ovary fuses with the female reproductive cell so sexual reproduction is basically fusion of male reproductive cell with the female reproductive cell. sperm and OVA are very important for reproduction in humans the young ones of some animals resemble parents and some smart when they emerge from eggs. search animals undergo a process called metamorphosis. some animals like earthworms are neither male not female they carry both male and female reproductive organs of animals are called bi sexual animals. Dolly was born on 5th July 1996 and was the first mammal to be cloned of Finn Dorset sheep by Ian Wilmut.
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Answer:
Notes of chapter class 8 reproduction in animals
Explanation:
Reproduction: It is one of the important life processes, which ensures the continuation of similar kinds of individuals (species) generation after generation.
Modes of Reproduction: There are two modes by which animals reproduce. These are
Sexual reproduction and
Asexual reproduction.
Sexual Reproduction
Male Reproductive Organs: Male reproductive organs are a pair of testes, sperm ducts, and a penis.
Sperms: The testes produce the male gametes called sperms.
Female Reproductive Organs: The female reproductive organs are a pair of ovaries, oviducts (fallopian tubes) and the uterus.
Asexual Reproduction: The type of reproduction in which only a single parent is involved, is called asexual reproduction.
Binary Fission: In binary fission, a single-celled individual reproduces by dividing itself into two. Example: Amoeba.
Budding: In this type of reproduction, a lateral bud arises from the body’ of the parent organism, it matures and gets detached from the body to behave as a new organism.
Eggs: Eggs (or Ova) are female gametes.
Embryo: Zygote, during its development, divides repeatedly to form a ball of cells. The cells then form groups to form tissues and ultimately organs of the body. This structure is called embryo.
Fertilization: The fusion of ovum and the sperm is called fertilization.
Internal Fertilisation: Fertilisation that takes place inside the female body is called internal fertilisation. This is observed in human beings and other animals such as cows and dogs.
External Fertilisation: Fertilisation that takes place outside the female body is called external fertilisation. This is common in aquatic animals such as frogs, fish, starfish, etc.
Foetus: It is the stage of embryo in which all the body parts are identifiable in its developmental stage.
Viviparous: Animals such as human beings, cows and dogs which give birth to the young ones are called Viviparous animals.
Oviparous: Animals such as hen, frog and butterfly which lay eggs are called oviparous animals.
Tadpoles: In the life process of a frog, we find three distinct stages, that is egg → tadpole → adult. These tadpoles get transformed into adults which are capable of jumping and swimming, and are finally transformed into frog.
Metamorphosis: The drastic change which transforms a larva into an adult in case of frog is called metamorphosis. •
Sexual Reproduction: The process of reproduction, which results from the fusion of male and female gametes is called sexual reproduction.
Sperms: The male gametes.
Ova: The female gametes.
Zygote: The nuclei of sperm(n) and egg(n) are fused during fertilization, to form a single nucleus. Egg after fertilization is called Zygote.
Cloning: Cloning is the creation of an organism that is an exact genetic copy of another. This means that every single bit of DNA is the same between the two organisms.