Reproduction

The female reproductive cell, or female gamete, in humans is the egg, also called the ovum. It can fuse with a sperm during fertilisation.

Sperm cells are produced in the testes, the male reproductive organs responsible for sperm production.

Eggs (ova) are produced in the ovaries, which are the female reproductive organs responsible for producing them.

In humans, a sperm usually meets and fuses with an egg in the fallopian tube, also called the oviduct.

The fusion of the male and female gametes forms a single cell called a zygote. The zygote then divides and develops into an embryo.

After implantation, the embryo develops in the uterus, where it continues to grow.

The placenta allows oxygen and nutrients to pass from the mother to the embryo and helps carry waste products away. The two blood supplies normally do not mix directly.

If pregnancy does not occur, the uterine lining that had thickened during the menstrual cycle breaks down and leaves the body with blood. This is menstruation.

At puberty, changes in hormone levels trigger many physical changes, including the development of reproductive functions.

Sperm are produced in the testes. Their position in the scrotum outside the main body cavity helps keep them slightly cooler than core body temperature, which supports sperm production.

Contraception refers to methods used to prevent pregnancy or reduce the chance of it occurring. Condoms can also reduce the risk of some sexually transmitted infections.

A condom acts as a physical barrier that helps prevent sperm from reaching the egg, so it is classified as a barrier contraceptive method.

Sterilisation is a surgical contraceptive method. Procedures such as vasectomy or tubal ligation block reproductive ducts, preventing sperm and egg from meeting.

Many sexually transmitted infections can spread through sexual contact with an infected person, particularly when protection is not used. Some can also spread by other routes, such as infected blood.

Good personal hygiene, including keeping the genital area clean, helps reduce the risk of some infections. It does not prevent or cure every disease.

Organisms have a limited lifespan. Reproduction produces offspring that can form the next generation, allowing the species to continue over time.

The offspring receives its genetic information from one parent, and there is no fusion of gametes from two parents. As a result, it is usually very similar to that parent, although small differences can arise, for example through DNA-copying errors.

In sexual reproduction, male and female gametes fuse and bring together genetic information from two parents. The resulting combinations can differ among offspring, producing variation.

Growth increases the size or cell number of an existing organism. Reproduction produces a new organism, so the two processes have different roles.

In Rhizopus, spores have protective walls that help them survive unfavourable conditions. When conditions become favourable, a spore can germinate and grow into a new organism.

In vegetative propagation, a new plant grows from a part of a selected parent plant. The offspring are usually similar to that parent, so plants with desired traits can be multiplied quickly.

The stigma is the receptive tip of the pistil. It receives pollen grains, which may then grow a pollen tube towards the ovary for fertilisation.

The ovary is the lower part of the pistil and contains ovules. After fertilisation, the ovary usually develops into a fruit, while the fertilised ovules develop into seeds.

A sperm is the male gamete and an egg is the female gamete. Their fusion during fertilisation forms a zygote, the first cell of the developing offspring.

Individual organisms have limited lifespans, but reproduction produces new generations. This helps maintain the continuity of a species; sexual reproduction can also introduce variation among offspring.