The Survival of Species: Reproduction, Sex Organs, and Strategies

Comprehensive vocabulary flashcards covering anatomical terminology, sex organs, fertilisation, reproductive strategies, and biological adaptations across species from the unit.

Asexual reproduction

A method of creating offspring from a single parent, resulting in offspring that are genetically identical to the parent.

Sexual reproduction

A method of creating offspring from the fusion of sex cells from two parents of the same species, where offspring inherit half of their genetic material from each parent.

Reproduction

The biological process by which living things create offspring that belong to the same species and share their genetic information.

Species

A group of similar organisms that can breed with each other to produce offspring.

Population

A group of organisms of the same species living in the same place who are able to mate with each other and reproduce.

Genetic variation

Differences in features between individuals of the same species, which can help some offspring survive changing environmental conditions.

Gamete

A specialized sex cell containing half of a parent's genetic information, such as an ovum or a sperm cell.

Fertilisation

The joining of an ovum and a sperm cell to fuse together and form a zygote containing a complete set of genetic material.

Zygote

A single fertilised cell formed by the fusion of an ovum and a sperm cell, which subsequently splits into many cells to develop into an offspring.

Ovum

A female sex cell produced by the ovaries; it is the largest human cell because it contains nutrients needed to nourish developing offspring.

Sperm

A male sex cell produced by the testes that moves using its tail and contains mitochondria to supply energy for swimming.

Sex organ

A body part composed of tissues that is specialized for the purposes of sexual reproduction.

Ovary

A female reproductive organ that produces, matures, and releases ova (egg cells).

Fallopian tube

A tube in the female reproductive system that transports ova from an ovary toward the uterus.

Uterus

A pear-sized muscular female organ that houses, protects, and nourishes a developing fertilised egg as it grows into an embryo and fetus.

Cervix

The narrow opening that connects the lower part of the uterus to the vagina.

Vagina

A muscular tube connecting the cervix to the outside of the body, functioning as an internal sex organ.

Cloaca

A single shared external opening for the reproductive, urinary, and digestive systems, found commonly in birds, reptiles, amphibians, and certain mammals like koalas.

Testis

A male reproductive organ that produces sperm cells and male hormones.

Epididymis

A narrow, coiled tube where immature sperm cells are stored, develop, and become fully mature before transport.

Vas deferens

A sperm duct approximately $30\,\text{cm}$ long in humans that transports mature sperm from the epididymis toward the urethra and penis.

Seminal vesicles

Glands that secrete a sugar-rich fluid that provides energy to help sperm travel, making up about $80\%$ of semen volume.

Prostate gland

A gland that produces a fluid that nourishes and protects sperm genetic material, helping sperm swim faster and survive longer.

Urethra

A tube that carries urine from the bladder out of the body, and in males, also serves as the conduit for ejaculating sperm.

Penis

A male reproductive organ designed to deliver sperm into the female reproductive tract and remove urine from the body.

Levels of biological organisation

The structural hierarchy in living organisms where cells make up tissues, tissues make up organs, organs make up organ systems, and organ systems make up an organism.

Reproductive strategy

Any physiological or behavioural adaptation an organism uses to mate, fertilise, produce, or raise offspring to improve its species' chance of survival.

Courtship ritual

A specific animal behaviour—such as singing, dancing, displays of strength, or gift-giving—used to attract and secure a mate for reproduction.

Delayed fertilisation

A reproductive strategy in which mating occurs before winter hibernation, sperm is stored inside the female, and ovulation and fertilisation are delayed until spring.

Internal development

A reproductive strategy where embryos develop inside the parent's body, providing a higher offspring survival rate but yielding fewer offspring at one time.

External development

A reproductive strategy where eggs develop outside the parent's body, allowing large numbers of offspring to be produced at once, though each has a lower chance of individual survival.

In vitro fertilisation (IVF)

An assisted reproductive technology in which eggs and sperm are collected and fertilised outside the body in a laboratory dish before the developing embryo is placed into the uterus.

Koala reproductive anatomy

A specialized marsupial system where females possess two ovaries, two separate uteri, two cervices, and three vaginas (two lateral vaginas for sperm transport and a central birth canal leading to a cloaca), complemented by a male's two-headed penis.

Pseudo-penis

An enlarged external genital structure found in female spotted hyenas that mimics the male penis in size and through which urination, copulation, and childbirth occur.

Penis fencing

A mating contest between hermaphroditic flatworms in which both individuals duel using their penises to attempt to pierce the skin of the other and inject sperm.