What is homeostasis?
To maintain the constancy of internal environment despite varying external environmental conditions is called homeostasis.
Why do all the fresh water organisms have contractile vacuoles whereas , majority of marine organisms lack them?
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
Define the following terms and give one example for each:
(a)Commensalism (b)Parasitism
(c)Camouflage (d)Mutualism
(e)Interspecific competition
Do you agree that regional and local variations exist within each.biome? Substantiate your answer with suitable example.
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?
An orchid plant is growing on the branch of mango tree. How do you describe this interaction between the orchid and the mango tree?
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?
While living in and on the host species, the animal parasite has evolved certain adaptations. Describe these adaptations with examples.
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.
The following diagrams are the age pyramids of different populations. Comment on the status of these populations.
What is the ecological principle behind the biological control method of managing with pest insects?
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 high altitude areas have brighter sunlight and lower temperatures as compared to the plains?
Why do submerged plants receive weaker illumination than exposed floating plants in a lake?
A population of Paramoecium caudatum was grown in a culture medium. After 5 days the culture medium became pvercrowded with Paramoecium and had depleted nutrients. What will happen to the population and what type of growth curve will the population attain? Draw the growth curve.
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.
Does light factor affect the distribution of organisms? Write a brief note giving suitable examples of either plants or animals.
Give an example for:
(a)An endothermic animal
(b)An ectothermic animal
(c)An organism of benthic zone
Define heliophytes and sciophytes. Name a plant from your locality that is either heliophyte or sciophyte.
Which element is responsible for causing soil salinity? At what concentration does the soil become saline?
If a marine fish is placed in a fresh water aquarium, will the fish be able to survive? Why or why not?
Most living organisms cannot survive at temperature above 45 °C. How are some microbes able to live in habitats with temperatures exceeding 100 °C?
If a fresh water fish is placed in an aquarium containing sea water, will the fish be able to survive? Explain giving reasons.
The density of a population in a habitat per unit area is measured in different units. Write the unit of measurement against the following:
a. Bacteria …………..
b. Banyan …………..
c. Deer …………..
d. Fish …………..
