FemaleAn organism's sex is female (symbol: ♀) if it produces the ovum (egg cell), the type of gamete (sex cell) that fuses with the male gamete (sperm cell) during sexual reproduction. A female has larger gametes than a male. Females and males are results of the anisogamousreproduction system, wherein gametes are of different sizes (unlike isogamy where they are the same size).
MeiosisMeiosis () is a special type of cell division of germ cells in sexually-reproducing organisms that produces the gametes: the sperm or egg cells. It involves two rounds of division that ultimately result in four cells, each with only one copy of each chromosome (haploid). Additionally, prior to the division, genetic material from the paternal and maternal copies of each chromosome is crossed over, creating new combinations of code on each chromosome.
SpeciesBasic unit of taxonomic classification, below genusThe hierarchy of biological classification's eight major taxonomic ranks. A genus contains one or more species. Minor intermediate ranks are not shown.A species (pl. species) is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity.
OrganismAn organism is any living thing that functions as an individual. Such a definition raises more problems than it solves, not least because the concept of an individual is also difficult. Several criteria, few of which are widely accepted, have been proposed to define what constitutes an organism. Among the most common is that an organism has autonomous reproduction, growth, and metabolism. This would exclude viruses, even though they evolve like organisms.
Reproductive successReproductive success is an individual's production of offspring per breeding event or lifetime. This is not limited by the number of offspring produced by one individual, but also the reproductive success of these offspring themselves. Reproductive success is different from fitness in that individual success is not necessarily a determinant for adaptive strength of a genotype since the effects of chance and the environment have no influence on those specific genes.
Genetic variationGenetic variation is the difference in DNA among individuals or the differences between populations among the same species. The multiple sources of genetic variation include mutation and genetic recombination. Mutations are the ultimate sources of genetic variation, but other mechanisms, such as genetic drift, contribute to it, as well.
MaleMale (symbol: ♂) is the sex of an organism that produces, or is organized to produce, the gamete (sex cell) known as sperm, which fuses with the larger female gamete, or ovum, in the process of fertilisation. A male organism cannot reproduce sexually without access to at least one ovum from a female, but some organisms can reproduce both sexually and asexually.
ExtinctionTermination of a species' lineageThe thylacine (Thylacinus cynocephalus) is an example of a recently extinct species.Palaeotherium is an example of an extinct genus that is only recorded from fossil records before the existence of hominids.Extinction is the termination of a species via the death of its last member. A taxon may become functionally extinct before the death of its last member if it loses the capacity to reproduce and recover.
Phenotypic plasticityPhenotypic plasticity refers to some of the changes in an organism's behavior, morphology and physiology in response to a unique environment. Fundamental to the way in which organisms cope with environmental variation, phenotypic plasticity encompasses all types of environmentally induced changes (e.g. morphological, physiological, behavioural, phenological) that may or may not be permanent throughout an individual's lifespan.
Charles DarwinCharles Robert Darwin ( DAR-win; 12 February 1809 – 19 April 1882) was an English naturalist, geologist, and biologist, widely known for his contributions to evolutionary biology. His proposition that all species of life have descended from a common ancestor is now generally accepted and considered a fundamental scientific concept.
DNA repairCellular mechanismDNA damage resulting in multiple broken chromosomesDiagram of DNA repair.In molecular biology, DNA repair is a collection of processes by which a cell identifies and corrects damage to the DNA molecules that encode its genome. A weakened capacity for DNA repair is a risk factor for the development of cancer.
BarnacleBarnacles are arthropods of the subclassCirripedia in the subphylum Crustacea. They are related to crabs and lobsters, with similar nauplius larvae. Barnacles are exclusively marine invertebrates; many species live in shallow and tidal waters. Some 2,100 species have been described. Barnacle adults are sessile; most are suspension feeders with hard calcareous shells, but the Rhizocephala are specialized parasites of other crustaceans, with reduced bodies.*As an Amazon Associate I earn from qualifying purchases.