Sexual Reproduction in Animals

Introduction

Developing a new organism by two parents using their sex cells or gametes is sexual reproduction. Male gametes unite with female gametes to produce a new cell called a zygote throughout this procedure. After some time has passed, this zygote will grow and mature into a new organism. Germ cells are another name for sex cells or gametes. Sexual reproduction is used by humans, fish, frogs, cats, dogs, and other animals.

• Male sex, female sex, gametes, sperms, ova or eggs, fertilization, zygote, and embryo are all terminology that is vital to understand when it comes to sexual reproduction in animals
• Male sex cells, known as sperms,’ are found in the body of a male animal, while female sex cells, known as ‘ova’ or ‘eggs,’ are located in the body of a female animal

Gametes are the cells that participate in sexual reproduction in animals or can be referred to as sexual reproductive cells. Male and female gametes are the two types of gametes. The male gamete in animals is sperm,’ whereas the female gamete is known as ‘ovum,’ or ‘egg.’ Also known as a female gamete or female sex cell, the ovum and egg are the same things. Ova is the plural form of an ovum. Water and food are kept in the ovum or egg, and the nucleus is a crucial component of the ovum. Sperm cells have long tails and are thousands of times smaller than an ovum or egg. Sperm are motile, meaning they can move around thanks to their tails.

Animal Sexual Reproduction 

1) Fertilization Before Conception

The events leading up to fertilization are included in this stage. The two processes that occur at this stage are gamete formation (gametogenesis) and gamete transfer. Gametes are sex cells that are naturally haploid (23 chromosomes) and distinct in females and males.

These gametes originate within unique structures in every creature. The male gamete is sperm, whereas the female gamete is ovum or egg. Male gametes must be moved to female gametes for fertilization since female gametes are immobile. Pollination is used to perform pre-fertilization in plants. Sexual intercourse is how unisexual animals transmit gametes.

2) Fertilisation

Fertilisation, also known as syngamy, is the process by which haploid male and female gametes encounter and combine to generate a zygote. External fertilization occurs outside the body, whereas internal fertilization occurs inside the body.

Fertilization enables the creation of a diploid zygote. The zygote eventually divides & develops into an embryo by mitotic division. Embryogenesis is the name given to this process. During development, cells differentiate and change in response to their environment. The organism, as well as its life cycle, has an impact on zygote development. Depending on whether the zygote grows in or out of the body, animals are classed as oviparous or viviparous. The zygote matures into the ovary in angiosperms, maturing into fruit, while the ovules develop into seeds.

Sexual Reproduction in Animals Examples

Reptile

Reptiles, an example of sexual reproduction in animals, for the most part, reproduce sexually. Cloacae are openings in females and male reptiles that allow eggs, sperm, and excrement to pass through. Intercourse is initiated by pressing the cloacae’s lips together, at which point the male sends his sperm to the female. The young are conceived in amniotic eggs laid by the female. However, a few species, such as most waterfowl & ostriches, have a phallus-shaped organ similar to the penis of mammals. Many male snakes use scents to locate females with internal fertilization.

Birds

Even though most male birds lack prominent sex organs, males have two testes that grow hundreds of times in size throughout the breeding season to create sperm. The female ovaries grow in size, albeit only the active left ovary. Before copulation, sperm is kept in the proctodeum compartment of the cloaca in males of animals without a phallus. The female moves her tail to the side during copulation while the male mounts her behind. In what is known as a cloacal kiss, he shifts the opening of his cloaca, or vent near hers, the sperm can penetrate the female’s cloaca. This can happen very quickly, sometimes in under a second.

Insects 

Insects account for more than two-thirds of all animal species on the planet. The majority of bug species reproduce sexually; however, others are parthenogenetic. Many insect species exhibit sexual dimorphism, while others have almost identical sexes. They are usually divided into two sexes, with men producing spermatozoa & females producing eggs. Before internal fertilization, the ova mature into eggs with a covering known as the chorion. Insects have a wide range of mating and reproductive techniques. Still, the most common one involves the male depositing spermatophore inside the female, which she reserves until she is ready to fertilize the eggs. In many species, the eggs are deposited outside the female after fertilization, the formation of a zygote, and varying degrees of development; in others, they develop further within the female and thus are born alive.

Mammals

Asexual reproduction in mammals is unknown, while some considered artificial cloning and the natural development of numerous clones from a single fertilized egg. It is done by some armadillos generating quadruplets through polyembryony, to be an example.

In monogamy, one male or one female has an exclusive mating relationship. While in polygamy, in which one or even more males have a whole relationship with one or more females, & promiscuity, in which any male and female will mate within the social group, are examples of mammal mating systems. Polygyny, polygamy in which one male has an exclusive relationship with one or more females, is the most prevalent mating arrangement among vertebrates. Few mammal species have monogamous relationships, but most birds do.

Conclusion

Organisms are genetically diverse because of sexual reproduction. Sexual reproduction begins with sperm and egg cells, which are produced through meiosis. Sexual reproduction occurs in a variety of ways in animals. In some species, such as fish, the male releases sperm over the eggs after the female has laid them. In other species, such as birds and most mammals—including human beings—the male releases sperm into the female reproductive tract. Some animals, such as earthworms, are hermaphroditic—they possess male and female sexual organs and can produce both sperm and eggs. They mate with other earthworms, however, to produce genetically diverse worms.