Download App

Organisms and Populations — BIOLOGY STD 12 Science — Question

Rajasthan BoardEnglish MediumSTD 12 ScienceBIOLOGYOrganisms and Populations4 Marks
Question
List the attributes that populations but not individuals possess.
✓

Answer

A population can be defined as a group of individuals of the same species residing in a particular geographical area at a particular time and functioning as a unit. For example, all human beings living at a particular place at a particular time constitute the population of humans. The main attributes or characteristics of a population residing in a given area are:
  1. Birth rate (Natality): It is the ratio of live births in an area to the population of an area. It is expressed as the number of individuals added to the population with respect to the members of the population.
  2. Death rate (Mortality): It is the ratio of deaths in an area to the population of an area. It is expressed as the loss of individuals with respect to the members of the population.
  3. Sex ratio: It is the number of males or females per thousand individuals.
  4. Age Distribution: It is the percentage of individuals of different ages in a given population. At any given time, the population is composed of individuals that are present in various age groups. The age distribution pattern is commonly represented through age pyramids.
  5. Population density: It is defined as the number of individuals of a population present per unit area at a given time.

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free

Explore more

More "4 Marks Questions" from Organisms and Populations→Organisms and Populations — all question types→BIOLOGY STD 12 Science question papers→Rajasthan Board STD 12 Science question papers→Rajasthan Board question paper generator→

Similar questions

It is commonly observed that parents feel embarrassed to discuss freely with their adolescent children about sexuality and reproduction. The result of this parental inhibition is that the children go astray sometimes.
  1. Explain the reasons that you feel are behind such embarrassment amongst some parents to freely discuss such issues with their growing children.
  2. By taking one example of a local plant and animal, how would you help these parents to overcome such inhibitions about reproduction and sexuality?
→
  1. A garden pea plant bearing terminal, violet flowers, when crossed with another pea plant bearing axial, violet flowers produced axial, violet flowers and axial, white flowers in the ratio of 3 : 1. Work out the cross showing the genotypes of the parent pea plants and their progeny.
  2. Name and state the law that can be derived from this cross and not from a monohybrid cross.
→
Where do transcription and translation occur inside a living cell? Briefly describe the three steps involved in the process of translation?
→
List the advantages of recombinant insulin.
→
Thalassemia and haemophilia are both Mendelian disorders related to blood. Write the symptoms of the diseases. Explain with the help of crosses the difference in the inheritance pattern of the two diseases.

OR

Why are thalassemia and hemophilia categorised as Mendelian disorders? Write the symptoms of these diseases. Explain their pattern of inheritance in humans. Write the genotypes of the normal parents producing a haemophilic son.

→
What are hallucinogens? Give two examples. Mention their clinical use, if
any.
→
Match the items of column A with those given in column B.
S. No
Column A
S. No
Column B
(i)
Eli Lilly
(a)
Cotton bollworm
(ii)
Pest resistance
(b)
Meloidegyne incognitia
(iii)
Crylab
(c)
Golden Rice
(iv)
CryIAC
(d)
Humulin
(v)
RNAi
(e)
Corn borer
(vi)
Vitamin A
(f)
Bt cotton
→
State and explain with the help of a cross, the law of segregation as proposed by Mendel.
→
(i) Explain the significance of each of the following features present in plants given below:, (a) In rose-bay plant the stamens ripen before the stigma., (b) In certain species of primrose, the flowers have short stamen and long style., (c) The bisexual flower of mustard exhibits rejection of self-pollen grain., (ii) Explain how autogamy is prevented in castor and papaya plant respectively.
→
How did Hershey and Chase differentiate between DNA and protein in their experiment while proving that DNA is the genetic material?
→