An individual and a population has certain characteristics. Name these attributes with definitions.
A population has certain attributes that an individual organism does not. An individual may have births and deaths, but a population has birth rates and death rates. In a population these rates refer to per capita births and deaths, respectively. The rates, hence, expressed as change in numbers (increase or decrease) with respect to members of the population.
• Another attribute characteristic of a population is sex ratio. An individual is either a male or a female but a population has a sex ratio (e.g., 60 per cent of the population are females and 40 per cent males).
• A population at any given time is composed of individuals of different ages. If the age distribution (per cent individuals of a given age or age group) is plotted for the population, the resulting structure is called an age pyramid. For human population, the age pyramids generally show age distribution of males and females in a combined diagram. The shape of the pyramids reflects the growth status of the population (a) whether it is growing, (b) stable or (c) declining.
Why do all the fresh water organisms have contractile vacuoles whereas , majority of marine organisms lack them?
Define the following terms and give one example for each:
(a)Commensalism (b)Parasitism
(c)Camouflage (d)Mutualism
(e)Interspecific competition
Lianas are vascular plants rooted in the ground and maintain erectness of their stem by making use of other trees for support. They do not maintain direct relation with those trees. Discuss the type of association the lianas have with the trees.
Give one example for each of the following types.
(a) Migratory animal (b) Camouflaged animal
(c) Predator animal (d) Biological control agent
(e) Phytophagous animal (f) Chemical defense agent
In a pond, we see plants which are free-floating; rooted-submerged; footed emergent; rooted with floating leaves. Write the type of plants against each of them.
If a population growing exponentially double in size in 3 years, what is the intrinsic rate of increase (r) of the population?
In an association of two animal species, one is a termite which feeds on wood and the other is a protozoan Trichonympha present in the gut of the termite. What type of association they establish?
What is the ecological principle behind the biological control method of managing with pest insects?
a. Label the three tiers 1, 2, 3 given in the above age pyramid.
b. What type of population growth is represented by the above age pyramid?
Do you agree that regional and local variations exist within each.biome? Substantiate your answer with suitable example.
An individual and a population has certain characteristics. Name these attributes with definitions.
In an aquarium two herbivorous species of fish are living together and feeding on phytoplanktons. As per the Gause's Principle, one of the species is to be eliminated in due course of time, but both are surviving well in the aquarium. Give possible reasons.
Write a short note on
(a)Adaptations of desert plants and animals
(b)Adaptations of plants to water scarcity
(c)Behavioural adaptations in animals
(d)Importance of light to plants
(e)Effect of temperature or water scarcity and the adaptations of animals.
If a marine fish is placed in a fresh water aquarium, will the fish be able to survive? Why or why not?
Observe the set of 4 figures A, B, C and D, and answer the following questions: •
(i) Which one of the figures shows mutualism?
(ii) What kind of association is shown in D?
(iii) Name the organisms and the association in C.
(iv) What role is the insect performing in B?
The following diagrams are the age pyramids of different populations. Comment on the status of these populations.
Which element is responsible for causing soil salinity? At what concentration does the soil become saline?
Most living organisms cannot survive at temperature above 45 °C. How are some microbes able to live in habitats with temperatures exceeding 100 °C?
Name the association in which one species produces poisonous substance or a change in environmental conditions that is harmful to another species.
Why do high altitude areas have brighter sunlight and lower temperatures as compared to the plains?
Define heliophytes and sciophytes. Name a plant from your locality that is either heliophyte or sciophyte.
Categorise the following plants into hydrophytes, halophytes, mesophytes and xerophytes. Give reasons for your answers.
a. Salvinia b. Opuntia
c. Rhizophora d. Mangifera
Why are coral reefs not found in the regions from. West Bengal to Andhra Pradesh but are found in Tamil Nadu and on the east coast of India?
Why do submerged plants receive weaker illumination than exposed floating plants in a lake?
