Types of Reproductive Systems in Animals with Examples
Reproduction is one of the fundamental attributes of all living beings; a biological process that helps to produce new individuals of similar species. Moreover, with the help of this process, similar organisms can enhance their genetic variability and species continuation.
Usually, a species reproduces through the mating of female and male organisms. The reproductive organs of any organism are called gonads. These gonads create gametes. Reproduction in animals occurs when a male gamete and a female gamete merge to produce a unicellular organism known as a zygote.
Types of Reproduction
The process of reproduction in animals can be categorised in two types. Based on the number of participants, reproduction modes are-
Sexual Reproduction
Asexual Reproduction
1. Sexual Reproduction
Both male and female parents are involved in sexual reproduction in animals. Sexual reproduction is the process of female and male gametes fusing to create new individuals.
Reproductive Organs in Animals
Reproductive organs of male include two testes, a penis, and sperm ducts. The testes produce sperms. The sperms are microscopic, and its structure has prominent three parts – a head, middle part and one tail.
Female gonads include two ovaries, oviducts, and one uterus. Ovaries create the eggs, and every month once the egg matures, it is transferred to the oviduct. The baby grows in the uterus.
Sexual Reproduction Process
Fertilisation
The first step of sexual reproduction in humans and animals is fertilisation. The male semen contains numerous sperms. By fusing one sperm with the egg, the fertilisation happens. During this process, the nuclei of both egg and sperm merge together to create a nucleus called zygote.
Two Types of Fertilisations are Found-
Internal Fertilisation
Internal fertilisation occurs inside the female body. Either sperm meet the egg through the reproductive tract of the female, or the males release the sperm and the females pick up and transfer the sperms in the reproductive tract.
Example- Human, other terrestrial animals like cow, dog, and some aquatic species, etc. Hence, reproduction in mammals occurs via external fertilisation.
There are Three Ways to Produce Offspring through Internal Fertilisation-
2. External Fertilisation
External fertilisation happens outside of the female body, mostly during spawning.
Example: Fish, frog, etc.
Development of Embryo
The unicellular zygote creates a ball of cells by several cell division, and this ball is called an embryo. Through implantation, this embryo gets attached to the uterus wall. Once the embryo starts developing organs and body parts, it is known as a foetus.
A child is a complete developed version of a foetus.
2. Asexual Reproduction
Contrarily, in the asexual reproduction process, a single organism can form new individuals irrespective of the gamete involvement and formation. Majorly, single –celled organisms take part in asexual reproduction. Furthermore, morphologically and genetically similar individuals are produced through this process.
Categories of Asexual Reproduction
Binary Fission
The parent cell divides into two identical cells containing one nucleus in each by mitosis.
Example: Euglena, amoeba, prokaryotes such as bacteria.
Fragmentation
Fragmentation is when an organism’s body breaks into different parts through any damage or otherwise, and each part develops into a single organism.
Example: Seastar.
Budding
In budding, offspring grows on the outer part of a parent body and stays attached until maturation. When it matures, it separates and starts living as a single organism.
Example: Hydra.
Regeneration
This is a modification of fragmentation where a completely new individual grows out of it.
Example: Echinoderm.
Parthenogenesis
In this asexual reproduction in animals, the development of egg occurs without fertilisation.
Example: Ant, bees, etc.
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FAQs on Reproductive System in Animals Explained
1. What is the main purpose of the reproductive system in animals?
The main purpose of the reproductive system is to create new individuals, or offspring. This biological process, known as reproduction, is essential for any species to continue its existence from one generation to the next.
2. What are the two primary ways that animals reproduce?
Animals use two primary methods for reproduction:
- Sexual Reproduction: This method requires two parents, a male and a female. It involves the fusion of specialised reproductive cells called gametes (sperm and egg) to create a genetically unique offspring.
- Asexual Reproduction: This method involves only a single parent. The offspring produced is genetically identical to the parent. Examples include budding in Hydra and binary fission in Amoeba.
3. Could you explain what happens during the process of fertilisation?
Fertilisation is a crucial step in sexual reproduction. It is the moment when a male gamete (sperm) successfully fuses with a female gamete (egg, or ovum). This fusion results in the formation of a single cell called a zygote, which contains genetic material from both parents and is the very first stage of a new animal's development.
4. Why is sexual reproduction generally considered more advantageous than asexual reproduction?
Sexual reproduction is considered more advantageous because it creates genetic variation in the offspring. By combining genes from two different parents, the new individual is unique. This variation within a species is crucial for adapting to changing environments, resisting diseases, and ensuring long-term survival, whereas asexually produced offspring are clones and share the same vulnerabilities.
5. What is the key difference between internal and external fertilisation?
The key difference lies in where the egg is fertilised. In internal fertilisation, the fusion of sperm and egg occurs inside the female parent's body. This is common in mammals, birds, and reptiles. In external fertilisation, the fusion happens outside the body, typically in an aquatic environment. Frogs and most fish release their eggs and sperm into the water for fertilisation to occur.
6. How do simple animals like Hydra reproduce without a partner?
Hydra reproduces asexually through a process called budding. In this method, a small outgrowth, or bud, develops on the parent's body. This bud grows, develops a mouth and tentacles, and eventually detaches from the parent to live as an independent, genetically identical individual.
7. What is the difference between oviparous and viviparous animals?
These terms describe how an animal's young develops and is born. Oviparous animals, like chickens and snakes, are egg-layers. The embryo develops inside an egg outside the mother's body. In contrast, viviparous animals, like humans, dogs, and whales, give birth to live young. The embryo develops inside the mother's body, receiving nourishment directly from her.
8. What is metamorphosis and which common animal is a good example of it?
Metamorphosis is a drastic physical transformation that some animals undergo from their larval stage to their adult form. A perfect example is the frog. It begins life as a fully aquatic larva called a tadpole, which breathes through gills. Through metamorphosis, it gradually loses its tail, develops lungs and legs, and transforms into a terrestrial adult frog.
