Endemism and Related Topics

Biodiversity hotspot

3 links

Biogeographic region with significant levels of biodiversity that is threatened by human habitation.

To qualify as a biodiversity hotspot on Myers' 2000 edition of the hotspot map, a region must meet two strict criteria: it must contain at least 1,500 species of vascular plants (more than 0.5% of the world's total) as endemics, and it has to have lost at least 70% of its primary vegetation.

A sampling of fungi collected during summer 2008 in Northern Saskatchewan mixed woods, near LaRonge, is an example regarding the species diversity of fungus. In this photo, there are also leaf lichens and mosses.

Biodiversity

3 links

Variety and variability of life on Earth.

Distribution of living terrestrial vertebrate species, highest concentration of diversity shown in red in equatorial regions, declining polewards (towards the blue end of the spectrum) (Mannion 2014)

Apparent marine fossil diversity during the Phanerozoic

Summer field in Belgium (Hamois). The blue flowers are Centaurea cyanus and the red are Papaver rhoeas.

The diverse forest canopy on Barro Colorado Island, Panama, yielded this display of different fruit

Agriculture production, pictured is a tractor and a chaser bin

Discovered and predicted total number of species on land and in the oceans

The Forest Landscape Integrity Index measures global anthropogenic modification on remaining forests annually. 0 = Most modification; 10= Least.

Deforestation and increased road-building in the Amazon Rainforest in Bolivia cause significant concern because of increased human encroachment upon wild areas, increased resource extraction and further threats to biodiversity.

Male Lophura nycthemera (silver pheasant), a native of East Asia that has been introduced into parts of Europe for ornamental reasons

The Yecoro wheat (right) cultivar is sensitive to salinity, plants resulting from a hybrid cross with cultivar W4910 (left) show greater tolerance to high salinity

Polar bears on the sea ice of the Arctic Ocean, near the North Pole. Climate change has started affecting bear populations.

Summary of major biodiversity-related environmental-change categories expressed as a percentage of human-driven change (in red) relative to baseline (blue)

A schematic image illustrating the relationship between biodiversity, ecosystem services, human well-being and poverty. The illustration shows where conservation action, strategies, and plans can influence the drivers of the current biodiversity crisis at local, regional, to global scales.

The retreat of Aletsch Glacier in the Swiss Alps (situation in 1979, 1991 and 2002), due to global warming.

Percentage of forest in legally protected areas, 2020, from the Food and Agriculture Organization publication The State of the World's Forests 2020. Forests, biodiversity and people – In brief

A great deal of work is occurring to preserve the natural characteristics of Hopetoun Falls, Australia while continuing to allow visitor access.

A biodiversity hotspot is a region with a high level of endemic species that have experienced great habitat loss.

European Last Glacial Maximum refugia, 20 kya.

Refugium (population biology)

2 links

Location which supports an isolated or relict population of a once more widespread species.

Two slopes with different sunlight exposure, only one is covered with snow

The Lake Pedder area had high geodiversity before it was flooded

This resulting isolation, in many cases, can be seen as only a temporary state; however, some refugia may be longstanding, thereby having many endemic species, not found elsewhere, which survive as relict populations.

A population becomes separated by a geographic barrier; reproductive isolation develops, resulting in two separate species.

Allopatric speciation

2 links

Mode of speciation that occurs when biological populations become geographically isolated from each other to an extent that prevents or interferes with gene flow.

In allopatric speciation, a species population becomes separated by a geographic barrier, whereby reproductive isolation evolves producing two separate species. From this, if a recently separated population comes in contact again, low fitness hybrids may form, but reinforcement acts to complete the speciation process.

In peripatric speciation, a small, isolated population on the periphery of a central population evolves reproductive isolation due to the reduction or elimination of gene flow between the two.

Allopatric speciation can result from mountain topography. Climatic changes can drive species into altitudinal zones—either valleys or peaks. Colored regions indicate distributions. As distributions are modified due to the change in suitable habitats, reproductive isolation can drive the formation of a new species.

A conceptual representation of species populations becoming isolated (blue and green) by the closure of the Isthmus of Panama (red circle). With the closure, North and South America became connected, allowing the exchange of species (purple). Grey arrows indicate the gradual movement of tectonic plates that resulted in the closure.

The red shading indicates the range of the bonobo (Pan paniscus). The blue shading indicates the range of the Common chimpanzee (Pan troglodytes). This is an example of allopatric speciation because they are divided by a natural barrier (the Congo River) and have no habitat in common. Other Pan subspecies are shown as well.

A simplification of an experiment where two vicariant lines of fruit flies were raised on harsh maltose and starch mediums respectively. The experiment was replicated with 8 populations; 4 with maltose and 4 with starch. Differences in adaptations were found for each population corresponding to the different mediums. Later investigation found that the populations evolved behavioral isolation as a pleiotropic by-product from this adaptive divergence. This form of pre-zygotic isolation is a prerequisite for speciation to occur.

Islands are often home to species endemics—existing only on an island and nowhere else in the world—with nearly all taxa residing on isolated islands sharing common ancestry with a species on the nearest continent.

Paleoendemism

1 links

Paleoendemism along with neoendemism is a possible subcategory of endemism.

Four of the 14 finch species found on the Galápagos Archipelago

Neoendemism

1 links

Neoendemism is one of two sub-categories of endemism, the ecological state of a species being unique to a defined geographic location.

Relict (biology)

1 links

Population or taxon of organisms that was more widespread or more diverse in the past.

This phenomenon differs from endemism in that the range of the population was not always restricted to the local region.

Cape sugarbird

0 links

Male drinking nectar from a Protea cynaroides in South Africa

The Cape sugarbird (Promerops cafer) is one of the eight bird species endemic to the Fynbos biome of the Western Cape and Eastern Cape provinces of South Africa.