Tag: extinctions

Questions Related to extinctions

Choose the correct answers from the alternatives given .
The Galapagos Islands are located near to the

zoology selection and evolution extinction extinctions environmental science

  1. West coast of Africa

  2. West coast of South America

  3. West coast of North America

  4. East coast of Australia

Show answer
Correct Option: B
Explanation:

The Galapagos islands are known for their large number of endemic species and were studied by Charles Darwin during the second voyage of HMS Beagle. His observations and collections contributed to the inception of Darwin's theory of evolution by means of natural selection. The islands are located in the eastern Pacific Ocean, near the west coast of South America.

So, the correct option is 'West coast of South America'.

According to IUCN, some of the recent extinctions include
(i) Dodo                     (ii) Quagga
(iii) Indian gazelle     (iv) Thylacine 
(v) Steller's sea cow (vi) Bali- subspecies of tiger 

zoology selection and evolution extinction extinctions environmental science

  1. (i), (ii), (iii) and (iv)

  2. (ii), (iii), (iv) and (vi)

  3. (i), (ii), (iv) and (v)

  4. (iii), (iv), (v) and (vi)

Show answer
Correct Option: C
Explanation:
The IUCN Red List of Threatened Species (also known as the IUCN Red List or Red Data List), founded in 1965, has evolved to become the world's most comprehensive inventory of the global conservation status of biological species. It uses a set of criteria to evaluate the extinction risk of thousands of species and subspecies. These criteria are relevant to all species and all regions of the world. With its strong scientific base, the IUCN Red List is recognized as the most authoritative guide to the status of biological diversity. A series of Regional Red List are produced by countries or organizations, which assess the risk of extinction to species within a political management unit. The IUCN Red List is set upon precise criteria to evaluate the extinction risk of thousands of species and subspecies. These criteria are relevant to all species and all regions of the world. The aim is to convey the urgency of conservation issues to the public and policy makers, as well as help the international community to try to reduce species extinction. Species such as Dodo, Quagga, Thylacine and Steller's sea cow are recent extinctions.
So the correct option is '(i), (ii), (iv) and (v)'. 

An exotic species that is introduced to a new area, spreads rapidly and eliminates native species is called 

zoology selection and evolution extinction extinctions environmental science

  1. immigrant species

  2. invasive species

  3. destructive species

  4. none of these.

Show answer
Correct Option: B
Explanation:

An invasive species is a species that is not native to a specific location (an introduced species), and that has a tendency to spread to a degree believed to cause damage to the environment, human economy or human health. The criteria for invasive species has been controversial, as widely divergent perceptions exist among researchers as well as concerns with the subjectivity of the term "invasive". Several alternate usages of the term have been proposed. The term as most often used applies to introduced species (also called "non-indigenous" or "non-native") that adversely affect the habitats and bioregions they invade economically, environmentally, or ecologically. Such invasive species may be either plants or animals and may disrupt by dominating a region, wilderness areas, particular habitats, or wildland–urban interface land from loss of natural controls (such as predators or herbivores).

So teh correct option is 'invasive species'.

Choose the correct answers from the alternatives given.
The biological definition of a species depends on

zoology selection and evolution extinction extinctions environmental science

  1. differences in the adaptations of two groups of organisms

  2. reproductive isolation of two groups of organisms

  3. anatomical and developmental differences between two groups of organisms

  4. geographic distribution of two groups of organisms

Show answer
Correct Option: B
Explanation:

Species a group of closely related organisms that are very similar to each other and are usually capable of interbreeding and producing fertile offspring. In reproductive isolation refers to the inability of related species to breed. In species, the only same member of an organism can interbreed due to reproductive isolation.

So the correct option is B, reproductive isolation of two groups of organisms.

Choose the correct answers from the alternatives given.
The continued occurrence of sickle-cell disease in parts of Africa with malaria is due to

zoology selection and evolution extinction extinctions environmental science

  1. Disruptive selection

  2. Continual mutation

  3. Fitness of the heterozygote

  4. Gene flow between populations

Show answer
Correct Option: C
Explanation:

Sickle cell anemia is an inherited blood disease where red blood cells show an abnormal crescent (or sickle) shape. It is an autosomal recessive disease in which one gene of allele codes for a normal protein and the other one codes for defective hemoglobin (sickle-celled). 


Heterozygous individuals ie., carrying just one copy of the sickle mutation (inherited from either the father or mother), do not develop sickle cell anemia. However, such individuals are protected against malaria. This defective hemoglobin cause sickling of RBC in which malarial parasite cannot survive. This explains the high prevalence of this mutation in parts of Africa, where malaria is endemic.

So the correct answer is "Fitness of the heterozygote"

Which of the following fish led to the extinction of an ecologically unique assemblage of more than 200 species of cichlid fish in the take Victoria of E. Africa?

zoology selection and evolution extinction extinctions environmental science

  1. Catla catla

  2. Dog fish

  3. Nile perch

  4. African catfish

Show answer
Correct Option: C
Explanation:
Nile perch, (species Lates niloticus), large food and game fish of the family Centropomidae (order Perciformes), found in the Nile and other rivers and lakes of Africa. A large-mouthed fish, the Nile perch is greenish or brownish above and silvery below and grows to about 1.8 m (6 feet) and 140 kg (300 pounds). It has an elongated body, a protruding lower jaw, a rounded tail, and two dorsal fins. In 1954, L. niloticus was introduced into Lake Victoria in Africa, home to hundreds of cichlid fishes. A powerful predator, the Nile perch has greatly reduced the cichlid numbers.
So the correct option is 'nile perch'.