Species

Species is the rudimentary unit of classification in biology and biodiversity. Spices are often defined as a large section of organism where two individuals of the opposite sexes produce fertile offspring. Moreover, types of species are identified and differentiated via their karyotype, morphology, ecological niche and their DNA sequences. 

What is Species in Biology?

Species definition in Biology indicates that it is a group of organisms that share a common genetic heritage. Moreover, they are competent to interbreed and produce fertile offspring in the process. 

However, species are separated from each other via different barriers. These barriers can be genetic or geographical.

Types of Species

There are different types of species that exist on this earth. However, they are broadly categorized into six concepts; these are – 

1. Biological Species Concept

In 1940, zoologist Mayr presented a widely accepted quotation of biological concepts. It was, “groups of actually or potentially interbreeding natural populations which are reproductively isolated from other such groups”. 

This theory explains that organisms distinct at a biological level do not interbreed with each other when budding in the same region. According to Mayr, species of these groups has specific characteristics, these are –

• Ecological Unit: 

Even though the members of a species are different from each other, they form a group together. They interact with other members of the species in any environment. 

• Reproductive Community: 

The members form a reproductive community and seek a partner within that group for reproduction. 

• Genetical Unit: 

A substantial intercommunicating gene pool exists with this group, allowing members to freely interbred. However, the individual elements are a temporary vessel containing a small portion of that gene pool.

This theory has gained reputation among scientists for years due to its simplicity. However, there are certain limitations of biological species concept, these are Asexual organisms do not come under this theory. Apomictic or asexual organisms display uniparental reproduction via apomixes, parthenogenesis, budding, etc.

Additionally, this theory is also not applicable for geographically isolated species (allopatric population).

2. Nominalistic Species Concept

This concept deals with the idea of individuals. The promoters of this theory believed that in nature, only individuals exist, and not any types of species. According to them, the concept of species is human-made and has no real existence in nature.

Moreover, they regarded it as a mental concept. This concept was popular during the 18th century and still has some followers in the world of botany.

3. Typological Species Concept

According to this concept, several diversities exist on earth, but in limited variations. Moreover, they do not have any relationship between them. In this concept, these universals are called species. However, it is irrelevant to consider variations in this topic.

4. Evolutionary Species Concept

To describe this species concept, Wiley in 1981 said evolutionary species “is a single lineage of ancestor-descendant populations of organisms which maintains its identity from other such lineages in space and time and which has its evolutionary tendencies and historical fate”.

Moreover, to include the species not considered under the biological species concept, this process was formed.

5. Ecological Species Concept

This concept studies ecological competition in an ecosystem. In simpler words, two similar categories of species have the same requirements; thus, their needs are likely to overlap. In a situation like this, they compete with each other for a particular resource.

6. Phylogenetic Species Concept

This concept classifies species in a particular group according to its ancestors. It claims that every individual within a species shares a certain resemblance with its lineage. However, this concept has a flaw. It is not easy to reconstruct an evolutionary pathway, even if so, it is not satisfactory all the time.

These classifications of various types of species rely on different theories developed over time. Similarly, like other theories, they have their flaws. Students can use the Vedantu app to access other methods of biology as well as other topics of the subject.

Concept of Species

Species form the basic manner by which biological organisms are classified. They are large broad sections of organisms, where two similar entities belonging to the same species produce offspring through the process of reproduction. Within the classification modes, there are karyotypes, morphology, DNA sequences, etc. which help specify and narrow down various biological organisms in a species. This article discusses the imminent extinction of various species and the impact it shall have on global biodiversity.

Extinction of Species

In the world globally, recent years, specifically the past few centuries have seen a rapid rise in extinction rates. There is a general agreement in the scientific and anthropological community that these rates of extinction can be directly correlated with human settlements in the past years, as men began to stop living a nomadic lifestyle and build a culture where they could settle down and engage in agriculture and other such practices. 

This period also represents a time where resources, specifically natural resources, were viewed on the basis of the utility they provided. If a certain species was utilitarian, like cattle and goats, i.e. they provided benefits either in terms of food, or monetary incentive for the primary sector, they were reared and preserved, but if there was no use for them, they were driven out of lands that increasingly were occupied by European colonialism, the expansion of mankind, increase in population, etc. which led to species extinction either naturally or man-induced. Natural degradation relied on “evolutionary” research, while man-induced research was based on “invasion” research.

At this moment, over 31% of amphibian species, 12% of bird species and 20% of mammal species are under threat of extinction according to the World Conservation Union’s (IUCN) global assessment of all known species. While these estimates exist, there is a lot of debate surrounding how many species are actually under threat, but there is a general consensus that at least over 1,00,000 species of living beings go extinct every year.

There are ways to determine the causes of extinction. At least based on the last five mass extinctions which took place, it can be noted that there are some commonalities between them, which can be listed as follows:

• There was an enormous loss of environmental or bio-diversity globally

• The loss was quite fast and rapid

• Taxonomically the impact of these was not random, i.e. it impacted large and entire groups of some species along with related species

• It did not necessarily follow a “survival of the fittest” rule and some species which were previously dominant survivors were still likely to go extinct

The sixth great extinction is on its way, and an understanding of circumstances that could lead to such extinction is imperative and necessary in today’s paradigm, as the potential impact it could have could be quite large and could affect human standards of living as well.

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