Comment on the growth curve given below.
A population growing in a habitat with limited resources show initially a lag phase, followed by phases of acceleration and deceleration and finally an asymptote, when the population density reaches the carrying capacity. A’ plot of N in relation to time (t) results in a sigmoid curve. This type of population growth is called Verhulst-Pearl Logistic Growth and is described by the following equation:
Why do all the fresh water organisms have contractile vacuoles whereas , majority of marine organisms lack them?
Does light factor affect the distribution of organisms? Write a brief note giving suitable examples of either plants or animals.
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.
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 an example for:
(a)An endothermic animal
(b)An ectothermic animal
(c)An organism of benthic zone
Which element is responsible for causing soil salinity? At what concentration does the soil become saline?
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.
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.
Why do submerged plants receive weaker illumination than exposed floating plants in a lake?
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?
Why do high altitude areas have brighter sunlight and lower temperatures as compared to the plains?
The following diagrams are the age pyramids of different populations. Comment on the status of these populations.
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?
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?
An orchid plant is growing on the branch of mango tree. How do you describe this interaction between the orchid and the mango tree?
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 …………..
What is the ecological principle behind the biological control method of managing with pest insects?
Categorise the following plants into hydrophytes, halophytes, mesophytes and xerophytes. Give reasons for your answers.
a. Salvinia b. Opuntia
c. Rhizophora d. Mangifera
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?
Give one example for each of the following:
(i) Eurythermal plant species ………………
(ii) A hot water spring organism ………………
(iii) An organism seen in deep ocean trenches ………………
(iv) An organism seen in compost pit ………………
(v) A parasitic angiosperm ………………
(vi) A stenothermal plant species ………………
(vii) Soil organism ………………
(viii) A benthic animal ………………
(ix) Antifreeze compound seen in antarcticfish ………………
(x) An organism which can conform ………………
While living in and on the host species, the animal parasite has evolved certain adaptations. Describe these adaptations with examples.
