Biological reproduction is the biological process by which new individual organisms are produced. Reproduction is a fundamental feature of all known life; each individual organism exists as the result of reproduction by an antecedent. The known methods of reproduction are broadly grouped into two main types: sexual and asexual reproduction.
In asexual reproduction, an individual can reproduce without involvement with another individual of that species. The division of a bacterial cell into two daughter cells is an example of as ...
Sexual reproduction is a biological process by which organisms create descendants that have a combination of genetic material contributed from two (usually) different members of the species. Each of two parent organisms contributes half of the offspring's genetic makeup by creating haploid gametes. Most organisms form two different types of gametes. In these anisogamous species, the two sexes are referred to as male (producing sperm or microspores) and female (producing ova or megaspores). In isogamous species the ...
Sexual reproduction is a biological process by which organisms create descendants that have a combination of genetic material contributed from two (usually) different members of the species. Each of two parent organisms contributes half of the offspring's genetic makeup by creating haploid gametes. Most organisms form two different types of gametes. In these anisogamous species, the two sexes are referred to as male (producing sperm or microspores) and female (producing ova or megaspores). In isogamous species the ...
Budding is a type of asexual reproduction. Budding - General biological meaning. A new organism is formed by the protrusion of part of another organism. When yeast buds, one cell becomes two cells. This is an example of reproduction. This is very common in plants, but may be found in animal organisms, such as the hydra, as well. Usually, the protrusion stays attached to the primary organism for a while, before becoming free. The new organism is naturally genetically identical to the primary one (a clone).Including:
Sex, in the scope of this article and category, refers to the male and female duality of biology and reproduction. The somewhat similar term gender has more to do with identity than biology. The concept is confined to organisms that reproduce sexually.
The female sex is defined as the one which produces the larger gamete (i.e., reproductive cell) and which typically bears the offspring. The category of sex reflects the biological reproductive function, rather than sexaulity or other behaviors. In some lower animals, sex may be assigned to specific structures rather than the entire organism as some species, such a ...
A life cycle is a period involving one generation of an organism, whether through asexual reproduction or sexual reproduction. In regard to its ploidy, there are three types of cycles:
haplontic life cycle
diplontic life cycle
diplobiontic life cycle (also referred to as diplohaplontic, haplodiplontic, or dibiontic life cycle)
These three types of cycles feature alternating haploid and diploid phases (n and 2n). Th ...
Budding is a type of asexual reproduction.
Budding - General biological meaning.
A new organism is formed by the protrusion of part of another organism. When yeast buds, one cell becomes two cells. This is an example of reproduction. This is very common in plants, but may be found in animal organisms, such as the hydra, as well. Usually, the protrusion stays attached to the primary organism for a while, before becoming free. The new organism is naturally genetically identical to the primary one (a clone).Including:
In botany, apomixis is biological reproduction without fertilization and without meiosis. An apomict or apomictic plant produces seeds that are genetically identical to the parent plant. Although the evolutionary advantages of sexual reproduction are lost, apomixis does pass along traits fortuitous for individual evolutionary fitness.
As apomictic plants are genetically identical from one generation to the next, each has the characters of a true species, maintaining distinctions from other congeneric apomicts, whi ...
A biological adaptation is an anatomical structure, physiological process or behavioral trait of an organism that has evolved over a period of time by the process of natural selection such that it increases the expected long-term reproductive success of the organism. The term adaptation is also sometimes used as a synonym for natural selection, but most biologists discourage this usage.
Adaptation can be viewed as taking place over geological time, or ...
Some unsolved problems in biology include:
Life. How did it start? Is life a cosmic phenomenon? Are the conditions necessary for the origin of life narrow or broad? How did life originate and diversify in hundred millions of years? Why, after rapid diversification, do microorganisms remain unchanged for millions of years? Did life start on this planet or was there an extraterrestrial intervention (for example a meteor from another planet)? Why have so many biological systems developed sexual reproduction? How do or
Alternation of generations is a term applied to a reproductive cycle of certain plants, fungi, and protists. It is a bit of a misnomer, a more accurate name would be "alternation of phases of a single generation" because a generation of a species typically encompasses one complete life cycle (i.e., both alternating phases; see Biological life cycle). The life cycle of organisms with so-called "alternation of generations" is characterized by each phase consisting of two separate, free-living organisms: a gametophyteIncluding:
A virus is a microscopic parasite that infects cells in biological organisms. Viruses are obligate intracellular parasites; they can reproduce only by invading and controlling other cells as they lack the cellular machinery for self-reproduction. The term virus usually refers to those particles that infect eukaryotes (multi-celled organisms and many single-celled organisms), while the term bacteriophage or phage is used to describe those infecting prokaryotes (bacteria and bacteria-like organisms lacking a nucleus ...
Asexual reproduction (also known as agamogenesis) is the simplest form of reproduction and does not involve meiosis, gamete formation, or fertilization. In laymen's terms, there is only one "parent" involved. This form of reproduction is common among simple organisms such as amoeba and other single-celled organisms, although most plants produce asexually as well (see vegetative reproduction).
Because it does not require male and female participation, asexual reproduction occurs faster than sexual reproduction and ...
Vegetative reproduction is asexual reproduction, but other terms that apply are vegetative propagation and vegetative multiplication. In essence it is any process by which new plant "individuals" arise or are obtained without production of seeds or spores. It is both a natural process in many plant species (including organisms that may or may not be considered "plants", such as bacteria and fungi) and one utilized or encouraged by horticu ...
Binary fission is the form of asexual reproduction used by most prokaryotes to reproduce. This process results in the reproduction of a living cell by division into two equal or near-equal parts.
Binary fission begins when the DNA replication occurs. Each circular DNA strand then attaches to the plasma membrane. The cell elongates, causing the two chromosomes to separate. The plasma membrane then invaginates (grows inwards) and splits the cell into two daughter cells through a process called cytokinesis.
Organisms that reproduce ...
Assortative mating (also called Assortative pairing) takes place when sexually reproducing organisms tend to mate with individuals that are like themselves in some respect (positive assortative mating) or dissimilar (negative assortative mating). In evolution, therefore these two types of assortative mating have the effect of reducing and expanding the range of variation, respectively, when the assorting is cued on heritable traits.
In biology and ecology, an organism (in Greek organon = instrument) is a complex adaptive system of organs that influence each other in such a way that they function as a more or less stable whole and have properties of life.
The origin of life and the relationships between its major lineages are controversial. Two main grades may be distinguished, the prokaryotes and eukaryotes. The prokaryotes are generally considered to represent two separate domains, called the Bacteria and Archaea, which are not closer to one anothe ...
Biological dispersal refers to those processes by which a species maintains or expands the distribution of a population. Dispersal implies movement—movement away from an existing population (population expansion) or away from the parent organisms (population maintenance). In the latter case, dispersal may simply involve replacement of the parent generation by the new generation, with only minor changes in geographic area occupied. In either case, dispersal is important because new life must replace old, and the two generations canno ...
Darwinism is a term for the underlying theory in the ideas of Charles Darwin, particularly concerning evolution and natural selection. Discussions of Darwinism usually focus on evolution by natural selection. The term is mostly used by its enemies. As biologist E.O. Wilson has noted, "Scientists don't call it 'Darwinism'." [Newsweek Nov 28, 2005]
Darwinism - Darwinism and other -isms.
The term "Darwinism" is most commonly used by creationists as a somewhat derogatory term for "evolutionary bio ...
