Types of reproduction: what they are and what they consist of

What are the types of reproduction?

The reproduction of living beings is a biological process by which organisms create offspring, which is of vital importance to perpetuate species. Two types of reproduction are recognized: sexual reproduction and asexual reproduction, which in turn are subdivided into others. Let's look at each one below.

Asexual reproduction

Asexual reproduction is one where only one parent is needed to create an offspring organism. In this type of reproduction, a parent individual fragments, splits, or splits, giving rise to one or more individuals with the same genetic load, unless a mutation occurs.

Asexual reproduction can occur in both unicellular and multicellular organisms. It has the peculiarity of generating identical offspring.

Types of asexual reproduction

There are various types of asexual reproduction, such as binary fission, parthenogenesis, budding, fragmentation, sporulation, and vegetative multiplication.

Binary fission

A parent organism duplicates its DNA and thereafter divides into two identical cells.

For example, bacteria and archaea.

Fragmentation

The parent organism fragments or splits. From this fragment, another individual with the same characteristics is generated.

For example, corals and starfish.

Gemmation

Asexual reproduction stages of a hydra (budding).

The parent organism generates a shoot that, when detached, gives rise to another organism.

For example, certain yeasts and sponges.

sporulation

The parent organism creates spores from which a new organism is formed.

For example, mold.

Parthenogenesis

It is produced from unfertilized female sex cells that give rise to another life. Although a female sex cell is involved, parthenogenesis is considered asexual because it is generated from a single-parent individual.

For example, bees and certain types of insects.

vegetative multiplication

It consists of the formation of new organisms from one part of another, such as a bulb, tubers, or rhizomes.

For example, sweet potatoes.

sexual reproduction

Sexual reproduction is one that requires two parents, one female and one male. Therefore, the offspring obtained are similar (not identical).

Through a process of cellular reproduction called meiosis, each parent generates gametes (female and male, respectively), which carry half of the genetic material that makes up a somatic cell.

When the gametes come into contact, fertilization occurs, resulting in the creation of a zygote. The zygote is the cell from which a new living being is generated.

For the gametes to come into contact, a fertilization process is necessary. Fertilization can be done in three different ways: internal, external, and autogamy.

internal fertilization

Through mating, the gametes are fertilized and develop within the female. Note: the Hippocampus kuda, known as a seahorse, is an exception to this rule as it is the only male capable of becoming pregnant.

For example, viviparous animals, including lions, zebras, apes, and humans.

external fertilization

The parents shed sex cells into the environment, where fertilization occurs. It is common in the aquatic environment.

For example, vertebrate fish, crustaceans, and a large part of the algae, all belonging to the oviparous group.

Autogamy

Own organisms with female and male sexual organs at the same time (hermaphrodites). These organisms can fertilize themselves under specific conditions.

For example, some species of flowers, among which roses and wheat flowers stand out.

Types of sexual reproduction

From a specialized point of view, sexual reproduction can be classified according to the morphological characteristics of the gametes.

isogamic sexual reproduction

It takes its name from the Greek terms iso, meaning 'equal', and gamos, meaning 'marriage'. Corresponds to those species where the gametes of each parent are equal in size and shape. Therefore, it is not possible to distinguish between feminine and masculine.

For example, the reproduction of some kinds of fungi.

anisogamic sexual reproduction

It takes its name from the Greek terms an, meaning 'negation or lack', iso, meaning 'equal', and gamos, meaning 'marriage'. Corresponds to those species where the gametes of each parent differ in shape and size. This is the case of sperm and eggs.

For example, most mammals, such as cats, dogs, or horses.

sexual reproduction in animals

The modalities or forms of sexual reproduction in animals include viviparity, viviparity, or oviparity (which includes ovuliparity).

Viviparity

In viviparous animals, fertilization and development of the embryo occur inside the female, responding to internal fertilization.

For example, most mammals (with the exception of platypuses and echidnas). Therefore, human reproduction obeys this pattern.

oviparity

Oviparous animals are those whose females lay eggs. These are fertilized by the male before spawning.

For example, birds and most reptiles.

Ovuliparity

Frog eggs.

Ovuliparity is a variant of oviparity. Applies to animals whose egg fertilization occurs after spawning. It qualifies as external fertilization. It occurs in aquatic species.

For example, most of the fish, some crustaceans, and certain amphibians such as frogs.

viviparity

In ovoviviparous animals, fertilization and development of the egg take place inside the female, so that the new organism is ready for hatching after spawning.

For example, the viper asp and sharks.

sexual reproduction in plants

Plants reproduce through a process called pollination, whether it is anemophilous (induced by wind), hydrophilic (induced by water), or zoophilic (induced by animals).

Two basic types of sexual reproduction in plants are known: reproduction in angiosperms (flowers) and in gymnosperms (seeds without flowers).

sexual reproduction in angiosperms

Angiosperms refer to flowering plants, in which the reproductive organs of the species are found.

For example, orange trees, coffee trees, and apple trees.

sexual reproduction in gymnosperms

Gymnosperms refer to plants without flowers, called conifers. These plants contain cubits that carry the seeds.

For example, pines and cedars.

 

human reproduction

Human reproduction is a clear example of anisogamic sexual reproduction by internal fertilization. Humans belong to the group of viviparous animals.

The human reproduction process consists of different stages.

• Coitus: refers to the copulative act that allows the man to introduce the male gametes (sperm) into the female reproductive system.
• Fertilization: is the following process, in which the sperm unites with the female gamete (oocyte), resulting in the formation of a zygote.
• Implantation: occurs when the zygote, converted into an embryo, implants itself in the walls of the uterus to develop.
• Organogenesis: is the stage in which the embryo develops its main organs.
• Fetal development: it is the final stage when the embryo becomes a fetus and completes its development process.

 

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