129 relations: Allele, Amphiprioninae, Androdioecy, Anglerfish, Animal coloration, Animal sexual behaviour, Anisogamy, Ant, Apterygota, Arachnid, Autogamy, Autosome, Bacterial conjugation, Baker's yeast, Bat, Biological dispersal, Caenorhabditis elegans, Cell (biology), Chromosomal crossover, Chromosome, Cloaca, Common descent, Conifer cone, Crustacean, Cryptogam, Developmental biology, Dicranum, Dikarya, DNA, Dragonfly, Drosophila melanogaster, Egg, Egg cell, Elephant seal, Environmental sex determination, Eukaryote, Evolution, Exopterygota, External fertilization, Female, Fern, Fertilisation, Field cricket, Fitness (biology), Flagellum, Flower, Fungus, Gamete, Genetics, Gestation, ..., Gonad, Grasshopper, Gynoecium, Handicap principle, Haplodiploidy, Hermaphrodite, Honey bee, Hummingbird, Insemination, Internal fertilization, Intersex, Intraspecific competition, Intromittent organ, Isogamy, Latrodectus mactans, Macmillan Publishers, Malaria, Male, Mammal, Mate choice, Mating, Mating type, Meiosis, Mitosis, Motility, Multicellular organism, Mushroom, Nature (journal), Organism, Ovary, Ovule, Oxford University Press, Palaeoptera, Parasitism, Penis, Pine, Pinophyta, Platypus, Ploidy, Pollen, Pollen tube, Pollination, Polygyny, Protist, Seed, Semen, Sequential hermaphroditism, Sex and gender distinction, Sex assignment, Sex differences in humans, Sex organ, Sex ratio, Sex steroid, Sex-determination system, Sexual dimorphism, Sexual intercourse, Sexual reproduction, Sexual selection, Silverfish, Slate (magazine), Sperm, Spermatophyte, Spermatozoon, Sphaerocarpos, Spore, Stalk-eyed fly, Stamen, Stigma (botany), Temperature-dependent sex determination, Testicle, The Descent of Man, and Selection in Relation to Sex, Traumatic insemination, Uterus, Vagina, Wrasse, X0 sex-determination system, XY sex-determination system, Y chromosome, ZW sex-determination system. Expand index (79 more) » « Shrink index
An allele is a variant form of a given gene.
Clownfish or anemonefish are fishes from the subfamily Amphiprioninae in the family Pomacentridae.
Androdioecy is a reproductive system characterized by the coexistence of males and hermaphrodites.
Anglerfish are fish of the teleost order Lophiiformes.
Animal coloration is the general appearance of an animal resulting from the reflection or emission of light from its surfaces.
Animal sexual behaviour takes many different forms, including within the same species.
Anisogamy (also called heterogamy) is the form of sexual reproduction that involves the union or fusion of two gametes, which differ in size and/or form. (The related adjectives are anisogamous and anisogamic). The smaller gamete is considered to be male (sperm cell), whereas the larger gamete is regarded as female (egg cell). There are several types of anisogamy. Both gametes may be flagellated and therefore motile. Alternatively, both of the gametes may be non-flagellated. The latter situation occurs in some algae and plants. In the red alga Polysiphonia, non-motile eggs are fertilized by non-motile sperm. In flowering plants, the gametes are non-motile cells within gametophytes. The form of anisogamy that occurs in animals, including humans, is oogamy, where a large, non-motile egg (ovum) is fertilized by a small, motile sperm (spermatozoon). The egg is optimized for longevity, whereas the small sperm is optimized for motility and speed. The size and resources of the egg cell allow for the production of pheromones, which attract the swimming sperm cells.
Ants are eusocial insects of the family Formicidae and, along with the related wasps and bees, belong to the order Hymenoptera.
The name Apterygota is sometimes applied to a subclass of small, agile insects, distinguished from other insects by their lack of wings in the present and in their evolutionary history; notable examples are the silverfish, the firebrat, and the jumping bristletails.
Arachnids are a class (Arachnida) of joint-legged invertebrate animals (arthropods), in the subphylum Chelicerata.
Autogamy, or self-fertilization, refers to the fusion of two gametes that come from one individual.
An autosome is a chromosome that is not an allosome (a sex chromosome).
Bacterial conjugation is the transfer of genetic material between bacterial cells by direct cell-to-cell contact or by a bridge-like connection between two cells.
Baker's yeast is the common name for the strains of yeast commonly used as a leavening agent in baking bread and bakery products, where it converts the fermentable sugars present in the dough into carbon dioxide and ethanol.
Bats are mammals of the order Chiroptera; with their forelimbs adapted as wings, they are the only mammals naturally capable of true and sustained flight.
Biological dispersal refers to both the movement of individuals (animals, plants, fungi, bacteria, etc.) from their birth site to their breeding site ('natal dispersal'), as well as the movement from one breeding site to another ('breeding dispersal').
Caenorhabditis elegans is a free-living (not parasitic), transparent nematode (roundworm), about 1 mm in length, that lives in temperate soil environments.
The cell (from Latin cella, meaning "small room") is the basic structural, functional, and biological unit of all known living organisms.
Chromosomal crossover (or crossing over) is the exchange of genetic material between homologous chromosomes that results in recombinant chromosomes during sexual reproduction.
A chromosome (from Ancient Greek: χρωμόσωμα, chromosoma, chroma means colour, soma means body) is a DNA molecule with part or all of the genetic material (genome) of an organism.
In animal anatomy, a cloaca (plural cloacae or) is the posterior orifice that serves as the only opening for the digestive, reproductive, and urinary tracts (if present) of many vertebrate animals, opening at the vent.
Common descent describes how, in evolutionary biology, a group of organisms share a most recent common ancestor.
A cone (in formal botanical usage: strobilus, plural strobili) is an organ on plants in the division Pinophyta (conifers) that contains the reproductive structures.
Crustaceans (Crustacea) form a large, diverse arthropod taxon which includes such familiar animals as crabs, lobsters, crayfish, shrimp, krill, woodlice, and barnacles.
A cryptogam (scientific name Cryptogamae) is a plant (in the wide sense of the word) that reproduces by spores, without flowers or seeds.
Developmental biology is the study of the process by which animals and plants grow and develop.
Dicranum is a genus of mosses, also called wind-blown mosses or fork mosses.
Dikarya is a subkingdom of Fungi that includes the divisions Ascomycota and Basidiomycota, both of which in general produce dikaryons, may be filamentous or unicellular, but are always without flagella.
Deoxyribonucleic acid (DNA) is a thread-like chain of nucleotides carrying the genetic instructions used in the growth, development, functioning and reproduction of all known living organisms and many viruses.
A dragonfly is an insect belonging to the order Odonata, infraorder Anisoptera (from Greek ἄνισος anisos, "uneven" and πτερόν pteron, "wing", because the hindwing is broader than the forewing).
Drosophila melanogaster is a species of fly (the taxonomic order Diptera) in the family Drosophilidae.
An egg is the organic vessel containing the zygote in which an animal embryo develops until it can survive on its own; at which point the animal hatches.
The egg cell, or ovum (plural ova), is the female reproductive cell (gamete) in oogamous organisms.
Elephant seals are large, oceangoing earless seals in the genus Mirounga.
Environmental sex determination is the establishment of sex by a non-genetic cue, such as nutrient availability, experienced within a discrete period after conception.
Eukaryotes are organisms whose cells have a nucleus enclosed within membranes, unlike Prokaryotes (Bacteria and other Archaea).
Evolution is change in the heritable characteristics of biological populations over successive generations.
The Exopterygota, also known as Hemipterodea, are a superorder of insects of the subclass Pterygota in the infraclass Neoptera, in which the young resemble adults but have externally developing wings.
External fertilization is a male organism’s sperm fertilizing a female organism’s egg outside of the female’s body.
Female (♀) is the sex of an organism, or a part of an organism, that produces non-mobile ova (egg cells).
A fern is a member of a group of vascular plants that reproduce via spores and have neither seeds nor flowers.
Fertilisation or fertilization (see spelling differences), also known as generative fertilisation, conception, fecundation, syngamy and impregnation, is the fusion of gametes to initiate the development of a new individual organism.
Field crickets are insects of order Orthoptera.
Fitness (often denoted w or ω in population genetics models) is the quantitative representation of natural and sexual selection within evolutionary biology.
A flagellum (plural: flagella) is a lash-like appendage that protrudes from the cell body of certain bacterial and eukaryotic cells.
A flower, sometimes known as a bloom or blossom, is the reproductive structure found in flowering plants (plants of the division Magnoliophyta, also called angiosperms).
A fungus (plural: fungi or funguses) is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and molds, as well as the more familiar mushrooms.
A gamete (from Ancient Greek γαμετή gamete from gamein "to marry") is a haploid cell that fuses with another haploid cell during fertilization (conception) in organisms that sexually reproduce.
Genetics is the study of genes, genetic variation, and heredity in living organisms.
Gestation is the carrying of an embryo or fetus inside viviparous animals.
A gonad or sex gland or reproductive gland is a mixed gland that produces the gametes (sex cells) and sex hormones of an organism.
Grasshoppers are insects of the suborder Caelifera within the order Orthoptera, which includes crickets and their allies in the other suborder Ensifera.
Gynoecium (from Ancient Greek γυνή, gyne, meaning woman, and οἶκος, oikos, meaning house) is most commonly used as a collective term for the parts of a flower that produce ovules and ultimately develop into the fruit and seeds.
The handicap principle is a hypothesis originally proposed in 1975 by Israeli biologist Amotz Zahavi to explain how evolution may lead to "honest" or reliable signaling between animals which have an obvious motivation to bluff or deceive each other.
Haplodiploidy is a sex-determination system in which males develop from unfertilized eggs and are haploid, and females develop from fertilized eggs and are diploid.
In biology, a hermaphrodite is an organism that has complete or partial reproductive organs and produces gametes normally associated with both male and female sexes.
A honey bee (or honeybee) is any member of the genus Apis, primarily distinguished by the production and storage of honey and the construction of perennial, colonial nests from wax.
Hummingbirds are birds from the Americas that constitute the family Trochilidae.
Insemination is the deliberate introduction of sperm into a female animal or plant for the purpose of impregnating or fertilizing the female for sexual reproduction.
Internal fertilization is the union of an egg cell with a sperm during sexual reproduction inside the body of a parent.
Intersex people are born with any of several variations in sex characteristics including chromosomes, gonads, sex hormones, or genitals that, according to the UN Office of the High Commissioner for Human Rights, "do not fit the typical definitions for male or female bodies".
Intraspecific competition is an interaction in population ecology, whereby members of the same species compete for limited resources.
An intromittent organ is a general term for an external organ of a male organism that is specialized to deliver sperm during copulation.
Isogamy is a form of sexual reproduction that involves gametes of similar morphology (similar shape and size), differing in general only in allele expression in one or more mating-type regions. Because both gametes look alike, they cannot be classified as "male" or "female". Instead, organisms undergoing isogamy are said to have different mating types, most commonly noted as "+" and "−" strains, although in some species of Basidiomycota there are more than two mating types (designated by numbers or letters). In all cases, fertilization occurs when gametes of two different mating types fuse to form a zygote.
Latrodectus mactans, known as southern black widow or simply black widow, and the shoe-button spider, is a venomous species of spider in the genus Latrodectus.
Macmillan Publishers Ltd (occasionally known as the Macmillan Group) is an international publishing company owned by Holtzbrinck Publishing Group.
Malaria is a mosquito-borne infectious disease affecting humans and other animals caused by parasitic protozoans (a group of single-celled microorganisms) belonging to the Plasmodium type.
A male (♂) organism is the physiological sex that produces sperm.
Mammals are the vertebrates within the class Mammalia (from Latin mamma "breast"), a clade of endothermic amniotes distinguished from reptiles (including birds) by the possession of a neocortex (a region of the brain), hair, three middle ear bones, and mammary glands.
Mate choice, also known as intersexual selection, is an evolutionary process in which selection is dependent on the attractiveness of an individual's phenotypic traits.
In biology, mating (or mateing in British English) is the pairing of either opposite-sex or hermaphroditic organisms, usually for the purposes of sexual reproduction.
Mating types are molecular mechanisms that regulate compatibility in sexually reproducing eukaryotes.
Meiosis (from Greek μείωσις, meiosis, which means lessening) is a specialized type of cell division that reduces the chromosome number by half, creating four haploid cells, each genetically distinct from the parent cell that gave rise to them.
In cell biology, mitosis is a part of the cell cycle when replicated chromosomes are separated into two new nuclei.
Motility is the ability of an organism to move independently, using metabolic energy.
Multicellular organisms are organisms that consist of more than one cell, in contrast to unicellular organisms.
A mushroom, or toadstool, is the fleshy, spore-bearing fruiting body of a fungus, typically produced above ground on soil or on its food source.
Nature is a British multidisciplinary scientific journal, first published on 4 November 1869.
In biology, an organism (from Greek: ὀργανισμός, organismos) is any individual entity that exhibits the properties of life.
The ovary is an organ found in the female reproductive system that produces an ovum.
In seed plants, the ovule is the structure that gives rise to and contains the female reproductive cells.
Oxford University Press (OUP) is the largest university press in the world, and the second oldest after Cambridge University Press.
The name Palaeoptera has been traditionally applied to those ancestral groups of winged insects (most of them extinct) that lacked the ability to fold the wings back over the abdomen as characterizes the Neoptera.
In evolutionary biology, parasitism is a relationship between species, where one organism, the parasite, lives on or in another organism, the host, causing it some harm, and is adapted structurally to this way of life.
A penis (plural penises or penes) is the primary sexual organ that male animals use to inseminate sexually receptive mates (usually females and hermaphrodites) during copulation.
A pine is any conifer in the genus Pinus,, of the family Pinaceae.
The Pinophyta, also known as Coniferophyta or Coniferae, or commonly as conifers, are a division of vascular land plants containing a single extant class, Pinopsida.
The platypus (Ornithorhynchus anatinus), sometimes referred to as the duck-billed platypus, is a semiaquatic egg-laying mammal endemic to eastern Australia, including Tasmania.
Ploidy is the number of complete sets of chromosomes in a cell, and hence the number of possible alleles for autosomal and pseudoautosomal genes.
Pollen is a fine to coarse powdery substance comprising pollen grains which are male microgametophytes of seed plants, which produce male gametes (sperm cells).
A pollen tube is a tubular structure produced by the male gametophyte of seed plants when it germinates.
Pollination is the transfer of pollen from a male part of a plant to a female part of a plant, enabling later fertilisation and the production of seeds, most often by an animal or by wind.
Polygyny (from Neoclassical Greek πολυγυνία from πολύ- poly- "many", and γυνή gyne "woman" or "wife") is the most common and accepted form of polygamy, entailing the marriage of a man with several women.
A protist is any eukaryotic organism that has cells with nuclei and is not an animal, plant or fungus.
A seed is an embryonic plant enclosed in a protective outer covering.
Semen, also known as seminal fluid, is an organic fluid that may contain spermatozoa.
Sequential hermaphroditism (called dichogamy in botany) is a type of hermaphroditism that occurs in many fish, gastropods, and plants.
The distinction between sex and gender differentiates a person's biological sex (the anatomy of an individual's reproductive system, and secondary sex characteristics) from that person's gender, which can refer to either social roles based on the sex of the person (gender role) or personal identification of one's own gender based on an internal awareness (gender identity).
Sex assignment (sometimes known as gender assignment) is the determination of an infant's sex at birth.
Sex differences in humans have been studied in a variety of fields.
A sex organ (or reproductive organ) is any part of an animal's body that is involved in sexual reproduction.
The sex ratio is the ratio of males to females in a population.
Sex steroids, also known as gonadocorticoids and gonadal steroids, are steroid hormones that interact with vertebrate androgen or estrogen receptors.
A sex-determination system is a biological system that determines the development of sexual characteristics in an organism.
Sexual dimorphism is the condition where the two sexes of the same species exhibit different characteristics beyond the differences in their sexual organs.
Sexual intercourse (or coitus or copulation) is principally the insertion and thrusting of the penis, usually when erect, into the vagina for sexual pleasure, reproduction, or both.
Sexual reproduction is a form of reproduction where two morphologically distinct types of specialized reproductive cells called gametes fuse together, involving a female's large ovum (or egg) and a male's smaller sperm.
Sexual selection is a mode of natural selection where members of one biological sex choose mates of the other sex to mate with (intersexual selection), and compete with members of the same sex for access to members of the opposite sex (intrasexual selection).
A silverfish (Lepisma saccharina) is a small, wingless insect in the order Zygentoma (formerly Thysanura).
Slate is an online magazine that covers current affairs, politics, and culture in the United States from a liberal perspective.
Sperm is the male reproductive cell and is derived from the Greek word (σπέρμα) sperma (meaning "seed").
The spermatophytes, also known as phanerogams or phenogamae, comprise those plants that produce seeds, hence the alternative name seed plants.
A spermatozoon (pronounced, alternate spelling spermatozoön; plural spermatozoa; from σπέρμα "seed" and ζῷον "living being") is a motile sperm cell, or moving form of the haploid cell that is the male gamete.
Sphaerocarpos is a genus of plants known as bottle liverworts.
In biology, a spore is a unit of sexual or asexual reproduction that may be adapted for dispersal and for survival, often for extended periods of time, in unfavourable conditions.
Stalk-eyed flies are insects of the fly family Diopsidae.
The stamen (plural stamina or stamens) is the pollen-producing reproductive organ of a flower.
The stigma (plural: stigmata) is the receptive tip of a carpel, or of several fused carpels, in the gynoecium of a flower.
Temperature-dependent sex determination (TSD) is a type of environmental sex determination in which the temperatures experienced during embryonic/larval development determine the sex of the offspring.
The testicle or testis is the male reproductive gland in all animals, including humans.
The Descent of Man, and Selection in Relation to Sex is a book by English naturalist Charles Darwin, first published in 1871, which applies evolutionary theory to human evolution, and details his theory of sexual selection, a form of biological adaptation distinct from, yet interconnected with, natural selection.
Traumatic insemination, also known as hypodermic insemination, is the mating practice in some species of invertebrates in which the male pierces the female's abdomen with his aedeagus and injects his sperm through the wound into her abdominal cavity (hemocoel).
The uterus (from Latin "uterus", plural uteri) or womb is a major female hormone-responsive secondary sex organ of the reproductive system in humans and most other mammals.
In mammals, the vagina is the elastic, muscular part of the female genital tract.
The wrasses are a family, Labridae, of marine fish, many of which are brightly colored.
The X0 sex-determination system is a system that determines the sex of offspring among.
The XY sex-determination system is the sex-determination system found in humans, most other mammals, some insects (Drosophila), some snakes, and some plants (Ginkgo).
The Y chromosome is one of two sex chromosomes (allosomes) in mammals, including humans, and many other animals.
The ZW sex-determination system is a chromosomal system that determines the sex of offspring in birds, some fish and crustaceans such as the giant river prawn, some insects (including butterflies and moths), and some reptiles, including Komodo dragons.
Anatomical sex, Aphrodisiasm, Biological sex, Biological sexes, Genetic sex, Pseques, Secks, Seks, Sex (biological division), Sex in plants, Sex terms, Sex., Sexes, Sexs, Sexuality (biology), The word sex.