1. | Human foetus developing inside the uterus draws nourishment from the mother |
2. | Head louse living on the human scalp as well as laying eggs on human hair |
3. | The cuckoo (koel) lays its eggs in a crow's nest |
4. | The female Anopheles bites and sucks blood from humans |
Study the four statements (a–d) given below and select the two correct ones out of them:
a: | A lion eating a deer and a sparrow feeding on grain are ecologically similar in being consumers |
b: | Predator starfish Pisaster helps in maintaining species diversity of some invertebrates |
c: | Predators ultimately lead to the extinction of prey species |
d: | Production of chemicals such as nicotine and strychnine by plants is metabolic disorder |
The two correct statements are:
1. a and d
2. a and b
3. b and c
4. c and d
A country with a high rate of population growth took measures to reduce it. The figure below shows age-sex pyramids of populations. A and B are twenty years apart. Select the correct interpretation about them:
Interpretations
1. | 'A' is more recent and shows a slight reduction in the growth rate |
2. | 'B' is an earlier pyramid and shows stabilised growth rate |
3. | 'B' is more recent showing that the population is very young |
4. | 'A' is the earlier pyramid and no change has occurred in the growth rate |
The table below gives the populations(in thousands) of ten species(A--J) in four areas (a-d) consisting of the number of habitats given within brackets against each. Study the table and answer the question as follows:
which area out of a to d shows maximum species diversity?
1. b
2. c
3. a
4. d
The population of an insect species shows an explosive increase in numbers during the rainy season followed by its disappearance at the end of the season. What does this show?
1. | S-shaped or sigmoid growth of this insect |
2. | the food plants mature and die at the end of the rainy season |
3. | Its population growth curve is of J-type |
4. | The population of its predators increases enormously |
Geometric representation of age structure is a characteristic of:
1. Biotic community
2. Population
3. Landscape
4. Ecosystem
If the mean and the median pertaining to a certain character of a population are of the same value, the following is most likely to occur:
1. a normal distribution
2. a bi-modal distribution
3. a T-shaped curve
4. a skewed curve
A high density of elephant population in an area can result in:
1. mutualism
2. Intraspecific competition
3. Interspecific completion
4. Predation on one another
Praying mantis is a good example of:
1. Mullerian mimicry
2. Warning colouration
3. Social insects
4. Camouflage
The formula for exponential population growth is:
1. dt/dN= rN
2. dN/rN= dt
3. rN/dN= dt
4. dN/dt= rN