Define the following terms and give one example for each:
(a)Commensalism (b)Parasitism
(c)Camouflage (d)Mutualism
(e)Interspecific competition
(a)Commensalism is the association between organisms of different species in which one species benefits but does not apparent harm to the other. For example, in the large intestine of human being, bacteria Escherichia coli are present which helps in digestion.
(b)Parasitism is an association in which one organism lives on or in the body of another, from which it obtains its food. For example, the parasites of humans include fleas and lice, various bacteria, protozoans and fungi.
(c)Camouflage is a high degree of similarity between an animal and its visual environment, which enables it be disguished or concealed. For example, birds with necks and heads of contrasting colours are not easily recognised by their enemies under certain conditions.
(d)Mutualism is an association between two organisms of different species in which each partner benefits. For example, the cross fertilization or pollination of plant flowers by insects (sometimes by birds) is a mutual relation of wide occurrence and great importance, because many plants are self- sterile.
(e)Inter-specific competition can be defined as an interaction occurs between different species that share some environmental resource when this is in short supply. Inter-specific competition often results in the dominance of one species over another. For example, when two species of Paramoecium,Paramoecium caudatum and P.aurelia are confined in a closed containers with fixed amount of food, out of them one species always died out.
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.
In a sea shore, the benthic animals live in sandy, muddy and rocky substrata
and accordingly developed the following adaptations.
a. Burrowing
b. Building cubes
c. Holdfasts/peduncle
Find the suitable substratum against each adaptation.
What is the ecological principle behind the biological control method of managing with pest insects?
Most living organisms cannot survive at temperature above 45 °C. How are some microbes able to live in habitats with temperatures exceeding 100 °C?
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.
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
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?
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.
If a marine fish is placed in a fresh water aquarium, will the fish be able to survive? Why or why not?
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?
An individual and a population has certain characteristics. Name these attributes with definitions.
If a population growing exponentially double in size in 3 years, what is the intrinsic rate of increase (r) of the population?
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.
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.
While living in and on the host species, the animal parasite has evolved certain adaptations. Describe these adaptations with examples.
Categorise the following plants into hydrophytes, halophytes, mesophytes and xerophytes. Give reasons for your answers.
a. Salvinia b. Opuntia
c. Rhizophora d. Mangifera
Why do high altitude areas have brighter sunlight and lower temperatures as compared to the plains?
Which element is responsible for causing soil salinity? At what concentration does the soil become saline?
Give an example for:
(a)An endothermic animal
(b)An ectothermic animal
(c)An organism of benthic zone
Name the association in which one species produces poisonous substance or a change in environmental conditions that is harmful to another species.
