Module 3 Flashcards
(14 cards)
What is a species?
It depends on the species concept used in the context of the organism. The biological species concept is often used and states that a species is individuals of a population that can interbreed and have fertile offspring. Since there are organisms, such as bacteria that reproduce asexually, the concept cannot be applied. In general, species do not exist in nature; only the variation among individuals in traits and preferences for partners. If the difference is low between the two, the probability is high that they can reproduce, and vice versa. Other concepts are the phylogenetic, morphological, and ecological.
The scientific name of a species and classification?
Binominal nomenclature was introduced by Carolus Linnaeus and gave species a two-part name, E. coli, where the first name can be considered the genus (one box) and the second name (one box) for the species. The hierarchical classification system is based on the grouping of organisms according to their specific attributes. The system have the following ‘boxes’: Domain -> Kingdom -> Phyla -> Class -> Order -> Family -> Genus -> Species.
How species can arise and mantained?
Mechanisms for speciation – a collection of individuals with similar characteristics and shared gene pool. The evolutionary perspective gives that it is not static – nor discrete, species are not constant, and new species do not occur abruptly. Species changes gradually until considered that one or more new species have emerged. Adaptive speciation – driven by natural and sexual selection.
Anagenesis: A gradual change in the gene pool composition that leads to a transition from one species to a new species. Is due to directional selection or genetic drift.
Cladogenesis: The gene pool splits that leads to the formation of new species from one original form. The only process that can increase biodiversity. Due to reproductive isolation in combination with directional selection – allopatric speciation, or reproductive isolation in combination with genetic drift or mutation – allopatric speciation. To remain – reproductive barriers.
Anastomoses: Speciation because of hybridization that creates new species directly and requires that it can reproduce to maintain the new species. Allopolyploidi is a form of this where hybrids form a new species that result in an increased number of chromosomes.
Autopolyploid: New species form via gene duplication within a species. Can be used in the agriculture as it results in sterile.
Sympatric speciation: Disruptive selection in combo with reproductive isolation.
Prezygotic barriers: Habitat – Temporal – Behavioral – Mechanistic – Gamete isolation. The preferences of the ecological setting, breading season, mating behavior, anatomic, and no fusing of zygotes.
Postzygotic barriers: Hybrid fertility – Hybrid breakdown. Lower fertility in the hybrids and problems of reproducing in the 2nd generation.
Allopatric speciation: Not together because of directional selection and / or genetic drift in geographically separated populations. A reproductive isolation between populations because of directional selection or genetic drift that leads to the divergence of the two populations, and given time, the populations have evolved so differently that they can be considered two species. Provided that the barriers have been developed.
Gradualism vs Puntuated equilibrium?
Evolutionary gradualism and Punctuated equilibrium are two ways in which the evolution of a species can occur, separately or simultaneously. Gradualism is selection and variation that happens more gradually over a short period by natural selection of the individuals with the highest fitness. A gradual, slow, and constant change for the population. The second one suggests that when new species have formed, they show little or no significant changed over time. A more rapid change in the environment, or mutations, that lead to selection pressures to the new and highly excess available niches, which in turn adaptive radiation of new species. As seen in the fossil record in the different levels of strata, where some levels have disappeared.
Ring species?
A connected series of neighboring populations and they can breed with those nearby. At both ends of the ring, there are at least two populations no longer able to interbreed as barriers have separated them. They have become very distantly related and cannot interbreed even though they are technically the same species.
Hybrid breakdown?
First generation (F1) hybrids are viable and fertile, but further hybrid generations (F2 and backcrosses) may be inviable or sterile. Implying a post-zygotic barrier because of an incompatibility of interactive genes.
Sympatric speciation?
Disruptive selection in combo with reproductive isolation. Speciation in a population without geographical isolation due to – disruptive selection, polyploidization, or micro geographical isolation. Usually by disruptive selection as nature selects for trait that is not intermediate.
Alloptaric speciation?
Not together because of directional selection and / or genetic drift in geographically separated populations. A reproductive isolation between populations because of directional selection or genetic drift that leads to the divergence of the two populations, and given time, the populations have evolved so differently that they can be considered two species. Provided that the barriers have been developed.
Postzygotic barriers?
Hybrid fertility – Hybrid breakdown. Lower fertility in the hybrids and problems of reproducing in the 2nd generation.
Prezygotic barriers?
Habitat – Temporal – Behavioral – Mechanistic – Gamete isolation. The preferences of the ecological setting, breading season, mating behavior, anatomic, and no fusing of zygotes.
Anagenesis?
A gradual change in the gene pool composition that leads to a transition from one species to a new species. Is due to directional selection or genetic drift.
Cladogenesis?
The gene pool splits that leads to the formation of new species from one original form. The only process that can increase biodiversity. Due to reproductive isolation in combination with directional selection – allopatric speciation, or reproductive isolation in combination with genetic drift or mutation – allopatric speciation. To remain – reproductive barriers.
Anastomeses?
Speciation because of hybridization that creates new species directly and requires that it can reproduce to maintain the new species. Allopolyploidi is a form of this where hybrids form a new species that result in an increased number of chromosomes.
Autopolyploidi?
New species form via gene duplication within a species. Can be used in the agriculture as it results in sterile offspring.
