Tag: selection and evolution

Questions Related to selection and evolution

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

  1. immigrant species

  2. invasive species

  3. destructive species

  4. none of these.


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

  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


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

  1. Disruptive selection

  2. Continual mutation

  3. Fitness of the heterozygote

  4. Gene flow between populations


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?

  1. Catla catla

  2. Dog fish

  3. Nile perch

  4. African catfish


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'.

Who attempted to solve the mechanism of organic evolution for the first time?

  1. Haeckel

  2. De Vries

  3. Lamarck

  4. Darwin


Correct Option: A
Explanation:

Ernest Haeckel is the scientist who had contributed much to genetic evolutionary studies. He is the one who described: "Ontogeny recapitulates phylogeny".

Which species found in abundance?

  1. Species Evenness

  2. Species Dominance

  3. Species Diversity

  4. Species Richness


Correct Option: B

An experiment to prove that organic compounds were the basis of life, was performed by

  1. Oparin

  2. Miller

  3. Melvin

  4. Fox


Correct Option: B
Explanation:

Organic compounds essential for life can be produced by simple inorganic constituents that were the conclusion first derived by Miller and Urey on the basis of their experiment. They took the gases thought to be present in the primitive atmosphere in a sealed flask and exposed them to electric spark. Later on analysis of flask, many organic compounds could be recovered.

The first organisms were

  1. Primitive eukaryotes

  2. Aerobic bacteria

  3. Prokaryotic chemoautotrophs

  4. Photosynthetic


Correct Option: C
Explanation:

The first organisms that appeared on earth resembled single-celled life forms called archaea that can live in extreme environments such as hot springs and deep-sea vents. They were prokaryotic heterotrophs and used inorganic chemicals from the environment for carbon fixation and this process is called chemoautotrophy. They were anaerobic in nature because free oxygen was absent during primitive environment on earth.

Thus the correct answer is option C.

The earliest living organisms were

  1. Multicellular

  2. Eukaryotes

  3. Prokaryotes

  4. Photosynthesizes


Correct Option: C
Explanation:

The earliest living organisms were prokaryotes which later on evolved to give rise to eukaryotes and photosynthesizing organisms.

Nucleoprotein gave most probably the first sign of 

  1. Life

  2. Amino acid

  3. Soil

  4. Sugar


Correct Option: A
Explanation:
  • The giant nucleoprotein molecules were formed by the union of nucleic acid and protein molecules. These nucleoprotein particles were described as free-living genes. Nucleoproteins gave most probably the first sign of life.
  • Hence Nucleoprotein gave most probably the first sign of life.
  • So, the correct answer is 'Life'.