Comment on the following figure: I, II and III, A, B, C, D, G, P, Q, R, S are species.
Figure I It is a single population and all individuals are of the same species, i.e., a individuals interact among themselves and their environment intraspecific interaction.
Figure II It is a community and it contains three populations of species A, B and C. They interact with each other and their environment and is called interspecific interaction.
Figure III It is a biome. It contains three communities of which one is in climax and other two are in different stages of development. All three communities are in the same environment and they interact with each other and their environment.
An individual and a population has certain characteristics. Name these attributes with definitions.
An individual and a population has following certain attributes like pattern of distribution. dispersal biotic potential and gene pool. Phenomenon of distribution of individual within geographical boundaries of the population is termed as interapopulation dispersion or internal distribution patterns or dispersion.
Dispersal an individual is dispersed at one or another time during their life in a population which is revealed by immigration or emigration.
(i) Immigration is the number of individuals of the same species that have come into the habitat from elsewhere during a specified time period.
(ii) Emigration is the number of individuals of the population who exit or leave the habitat and go elsewhere during a specified time period.
Biotic Potential Biotic potential is the natural capacity of a population to increase its size under ideal environmental conditions.
Gene pool All the genotypes of all individuals in a breeding population is referred to as gene pool.
The following diagrams are the age pyramids of different populations. Comment on the status of these poulations.
Figure A It is a 'pyramid' shaped age pyramid. In this figure, the base, i.e., pre-reproductive stage is very large as compared with the reproductive and post-reproductive stages of the population. This type of age structure indicate that the population would increase rapidly.
Figure B It is an 'inverted bell' shaped pyramid. In this figure, the pre-reproductive and reproductive stages are same. This type of age structure indicates that the population is stable.
Figure C It is 'urn' shaped pyramid. In this figure, the pre-reproductive and reproductive stages are less than the post-reproductive stages of this population. In this population more older people are present. This type of age structure indicates that the population definitely is declining.
$$ \text { Comment on the growth curve given below. } $$
The growth curve shown above is logistic growth curve or S-shaped curve.
Logistic growth curve is considered more realistic because unlimited resources are not available in an ecosystem or in a habitat, where
$K$-stands for carrying capacity.
$N$-indicates population density, which is the number of species of a population per unit area.
$r$-is for intrinsic rate of natural increase.
A population of Paramecium caudatum was grown in a culture medium. After 5 days the culture medium became overcrowded with Paramecium and had depleted nutrients. What will happen to the population and what type of growth curve will the population attain? Draw the growth curve.
Initially, after a lag phase, the population will grow in an exponential manner as the nutrients and space will be abundant.
When the food sources get depleted, the population density starts decreasing and ends in an asymptote phase, then the population density reaches the carrying capacity (maximum number of individuals of a population or species that a given environment can sustain indefinitely).
The population shows a pattern of logistic growth giving an S-shaped curve.
Where $K=$ carrying capacity
$N=$ population density at time ' $t$ '
$r=$ Intrinsic rate of natural increase
