CBSE Class 12 Biology Organisms and Populations Cross Word

CBSE Class 12 Biology Organisms and Populations Cross Word. Please refer to the examination notes which you can use for preparing and revising for exams. These notes will help you to revise the concepts quickly and get good marks.

ORGANISMS AND POPULATIONS

(CROSS WORD)

Across:

3. It refers to the number of deaths in a population at a given period [1 Mark]

Answer:
1. Mortality

Teacher's Note:
a) Mortality represents the death rate within a population during a specified time frame.
b) It is one of the key parameters that decreases population density.

7. It is the process of spending the winters or very cold conditions in an inactive or dormant state to escape in time. [1 Mark]

Answer:
1. Hibernation

Teacher's Note:
a) Hibernation is a behavioral and physiological adaptation to tide over unfavorable cold stress.
b) Bears undergo hibernation to survive winter conditions.

9. It is the place where an organism lives. [1 Mark]

Answer:
1. Habitat

Teacher's Note:
a) Habitat refers to the physical environment and locality where an organism naturally resides.
b) It provides the necessary resources like food, shelter, and breeding sites.

10. These are the animals, which can tolerate only a very narrow range of temperature and are restricted in distribution. [1 Mark]

Answer:
1. Stenothermal

Teacher's Note:
a) Stenothermal organisms are restricted to narrow temperature zones.
b) Contrast with eurythermal organisms which tolerate wide temperature ranges.

15. Refers to the number of births added to the initial population during a given period. [1 Mark]

Answer:
1. Natality

Teacher's Note:
a) Natality refers to the birth rate in a population during a given time period.
b) It is a major factor contributing to an increase in population density.

17. It refers to the total number of individual species, present per unit area or volume, at a given time. [1 Mark]

Answer:
1. Population density

Teacher's Note:
a) Population density measures the size of a population in relation to a definite unit of space.
b) It is usually expressed in terms of number of individuals per unit area or volume.

18. It is the process of spending the dry hot periods or summers in an inactive or dormant state to escape in time. [1 Mark]

Answer:
1. Aestivation

Teacher's Note:
a) Aestivation helps animals escape summer-related heat and desiccation stress.
b) Seen in various snails and fish during dry seasons.

19. It is a stage of suspended development shown by many zooplankton species in fresh water bodies. [1 Mark]

Answer:
1. Diapause

Teacher's Note:
a) Diapause is a stage of suspended development exhibited under unfavorable environmental conditions.
b) Commonly observed in many zooplankton species inhabiting fresh water bodies.

Down:

1. These are the animals, which can tolerate a wide range of temperature and are geographically widely distributed. [1 Mark]

Answer:
1. Eurythermal

Teacher's Note:
a) Eurythermal organisms can successfully thrive across wide temperature fluctuations.
b) Such species usually have a broader geographical distribution range.

2. It is an interaction between species where one is harmed and the other is unaffected. [1 Mark]

Answer:
1. Amensalism

Teacher's Note:
a) Amensalism is a population interaction where one species is inhibited or harmed while the other remains unaffected.
b) Example includes the secretion of chemicals like penicillin by fungi harming bacteria.

4. Any morphological, physiological or behavioural attribute of an organism that enables it to survive and reproduce in its habitat. [1 Mark]

Answer:
1. Adaptation

Teacher's Note:
a) Adaptation is any genetic trait that enhances survival and reproductive fitness in a specific habitat.
b) Adaptations can be behavioral, physiological, or morphological.

5. It refers to the range of conditions an organism can tolerate, the resources it utilises and its distinct functional role in the ecological system. [1 Mark]

Answer:
1. Niche

Teacher's Note:
a) Ecological niche describes the functional role and space an organism occupies in an ecosystem.
b) No two species can occupy the exact same niche in a habitat indefinitely.

6. It is the maximum number of individuals of a population that can be sustained by a given habitat. [1 Mark]

Answer:
1. Carrying capacity

Teacher's Note:

a) Carrying capacity denotes the limit of environment support for a given population size.
b) Represented by the letter \(K\) in population growth equations.

8. It refers to the number of individuals of the same species that come into a habitat from elsewhere during the time period under consideration, [1 Mark]

Answer:
1. Immigration

Teacher's Note:
a) Immigration is the inward movement of individuals into a population from outside.
b) It contributes to an increase in local population density.

11. It refers to the number of individuals of the same species that left the habitat during the time period under consideration, [1 Mark]

Answer:
1. Emigration

Teacher's Note:
a) Emigration is the outward movement of individuals from a population to other habitats.
b) It results in a decrease in population density.

12. Those organisms which maintain a constant internal (within the body) environment (homeostasis), despite the fluctuations in the environment. [1 Mark]

Answer:
1. Regulators

Teacher's Note:
a) Regulators maintain homeostasis through physiological and sometimes behavioral means.
b) Birds and mammals are prime examples of thermoregulators and osmoregulators.

13. These are the animals, which can tolerate a very narrow range of salinity. [1 Mark]

Answer:
1. Stenohaline

Teacher's Note:
a) Stenohaline organisms are restricted to narrow salinity gradients.
b) Most freshwater or marine organisms cannot withstand drastic salinity changes.

14. It refers to the maintenance of a steady internal environment by organisms, [1 Mark]

Answer:
1. Homeostasis

Teacher's Note:
a) Homeostasis is the process of maintaining a constant steady internal state despite external fluctuations.
b) Essential for optimal enzyme activity and metabolic functioning.

16. These are the animals, which can tolerate a wide range of salinity. [1 Mark]

Answer:
1. Euryhaline

Teacher's Note:
a) Euryhaline organisms can tolerate wide fluctuations in salinity.
b) Examples include many estuarine organisms and migratory fish like salmon.

Useful revision material for CBSE Class 12 Biology Organisms and Populations Cross Word.