species-area relationship

Examples of species-area relationship in the following topics:

• Present-Time Extinctions

  • A second approach to estimating present-day extinction rates is to correlate species loss with habitat loss by measuring forest-area loss and understanding species-area relationships.
  • The species-area relationship is the rate at which new species are seen when the area surveyed is increased.
  • Recent work has also called into question the applicability of the species-area relationship when estimating the loss of species.
  • This work argues that the species-area relationship leads to an overestimate of extinction rates.
  • A better relationship to use may be the endemics-area relationship.

• Community Ecology and Ecosystem Ecology

  • A biological community consists of the different species within an area, typically a three-dimensional space, and the interactions within and among these species.
  • Mutualism is a form of a long-term relationship that has coevolved between two species and from which each species benefits.
  • For mutualism to exist between individual organisms, each species must receive some benefit from the other as a consequence of the relationship.
  • The ecosystem is composed of all the biotic components (living things) in an area along with that area's abiotic components (non-living things).
  • This mutualistic relationship is an example of a community ecological study, which aims to examine the interactions between different species living in an area.

• Biodiversity of Plants

  • The explosion of the human population, especially in tropical countries where birth rates are highest and economic development is in full swing, is leading to human encroachment into forested areas.
  • The number of plant species becoming extinct is increasing at an alarming rate.
  • Because ecosystems are in a delicate balance and because seed plants maintain close symbiotic relationships with animals, whether predators or pollinators, the disappearance of a single plant can lead to the extinction of connected animal species.
  • These unknown species are threatened by logging, habitat destruction, and loss of pollinators.
  • Efforts to preserve biodiversity take several lines of action, from preserving heirloom seeds to barcoding species.

• Speciation

  • Speciation is an event in which a single species may branch to form two or more new species.
  • Many species are similar enough that hybrid offspring are possible and may often occur in nature, but for the majority of species this rule generally holds.
  • Given the extraordinary diversity of life on the planet, there must be mechanisms for speciation: the formation of two species from one original species.
  • Biologists think of speciation events as the splitting of one ancestral species into two descendant species.
  • The diagram shows similarities to phylogenetic charts that are drawn today to illustrate the relationships of species.

• The Role of Species within Communities

  • Communities are shaped by foundation species and keystone species, while invasive species disrupt the natural balance of an area.
  • These include the foundation species, keystone species, and invasive species.
  • These species have many ways of entering foreign environments, including through ship's ballast water: when planes take off, organisms can sometimes become stuck in the cargo area.
  • In some areas of the Mississippi River, Asian carp species have become predominant, effectively outcompeting native fish for habitat.
  • When this animal is removed from certain areas, its prey species greatly alters the dynamics of the ecosystem, reducing biodiversity.

• Newly Discovered Eukaryotes

  • There are many new species to be discovered, including eukaryotic species.
  • The vast majority of Earth's species are microbial.
  • The inverse relationship of size and population recurs higher on the evolutionary ladder.
  • However, as suggested above most of the attention is given to large species, which represent a very small portion of the new species identified Even with this in mind, since the beginning of this century, 5 marsupial species, 25 primate, 1 elephant, 1 sloth, 3 rabbit, several rodent species, at least 30 new bat species have been discovered.
  • This graph shows how many species discovered (dark green) versus estimated species remaining to be discovered.

• Organismal Ecology and Population Ecology

  • Organismal and population ecology study the adaptations that allow organisms to live in a habitat and organisms' relationships to one another.
  • The adult butterflies feed on the nectar of flowers of wild lupine and other plant species.
  • A population is a group of interbreeding organisms that are members of the same species living in the same area at the same time.
  • Organisms that are all members of the same species, a population, are called conspecifics.
  • However, the distribution and density of this species is highly influenced by the distribution and abundance of wild lupine.

• Exotic Species

  • For this reason, exotic species, also called invasive species, can threaten other species through competition for resources, predation, or disease.
  • Invasive species that are closely related to rare native species have the potential to hybridize with the native species.
  • Invasive species cause competition for native species.
  • Islands do not make up a large area of land on the globe, but they do contain a disproportionate number of endemic species because of their isolation from mainland ancestors.
  • Describe the impact of exotic and invasive species on native species

• The Biological Species Concept

  • According to this definition, one species is distinguished from another when, in nature, it is not possible for matings between individuals from each species to produce fertile offspring.
  • The closer relationship two organisms share, the more DNA they have in common, just like people and their families.
  • Species' appearance can be misleading in suggesting an ability or inability to mate.
  • Populations of species share a gene pool: a collection of all the variants of genes in the species.
  • Species that appear similar may not be able to reproduce.

• Types of Biodiversity

  • A species' future potential for adaptation depends on the genetic diversity held in the genomes of the individuals in populations that make up the species.
  • A genus with very different types of species will have more genetic diversity than a genus with species that look alike and have similar ecologies.
  • It is also useful to define ecosystem diversity: the number of different ecosystems on the planet or in a given geographic area .
  • A recent estimate suggests that the number of identified eukaryote species, about 1.5 million species, account for less than 20 percent of the total number of eukaryote species present on the planet (8.7 million species, by one estimate) .
  • In addition, the unique characteristics of each species make it potentially valuable to humans or other species on which humans depend.