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Organisms and Populations

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Biology

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Biology

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CBSE Gujarat Board Haryana Board

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Class 10 Class 12

What is true about the isolated small tribal populations? 

  • There is a decline in population as boys marry girls only from their own tribe

  • Hereditary diseases like colour blindness do not spread in the isolated population

  • Wrestlers who develop strong body muscles in their lifetime pass this character on their progeny

  • There is no change in population size as they have a large gene pool


B.

Hereditary diseases like colour blindness do not spread in the isolated population

The population can be defined as a group or assemblage of organisms of the same species that live at a given time in a particular area. In human beings a dominant X- linked gene is necessary for the formation of colour sensitive cells the cones, in the retina of the eye. The recessive form of this gene is incapable of producing the colour sensitive cones and homozygous recessive female and hemizygous recessive males are unable to distinguish between these two colours. As the isolated population do not have any hereditary diseases like colour blindness, so they do not spread accordingly.

According to the theory of inheritance of acquired characters of Lamarck the Wrestlers, who develop strong body muscles in their lifetime, must pass this character onto their progeny, but this is not found true.
Gene pool is defined as the sum total of genes present in a Mendelian population. The study of gene pools tells us the total number of genes, their kinds and variety present in the population.

The population can be defined as a group or assemblage of organisms of the same species that live at a given time in a particular area. In human beings a dominant X- linked gene is necessary for the formation of colour sensitive cells the cones, in the retina of the eye. The recessive form of this gene is incapable of producing the colour sensitive cones and homozygous recessive female and hemizygous recessive males are unable to distinguish between these two colours. As the isolated population do not have any hereditary diseases like colour blindness, so they do not spread accordingly.

According to the theory of inheritance of acquired characters of Lamarck the Wrestlers, who develop strong body muscles in their lifetime, must pass this character onto their progeny, but this is not found true.
Gene pool is defined as the sum total of genes present in a Mendelian population. The study of gene pools tells us the total number of genes, their kinds and variety present in the population.


The number of births during a given period in the
population that are added to the initial density is 

 :
  • Natality
  • Mortality
  • Migration
  • Immigration

A.

Natality

Population density is denoted by the symbol
  • N
  • D
  • M
  • D

A.

N

To live in groups is beneficial because :
  • feeling of security
  • can obtain food easily
  • Partner is available for mating
  • All the above

D.

All the above

The departure of a individual from a population is called :
  • Natality 
  • Mortality
  • Immigration 
  • Emigration

D.

Emigration

Ants give information to their companions :
  • by dancing
  • by secretion of pheromones
  • by making sound
  • by defecating

B.

by secretion of pheromones