Chapter 3.1, Problem 1NV

Summary Introduction

To fill:

The blanks with correct terms.

Introduction:

Ecological succession can be described as the establishment of a new biological community. It is of two types - primary and secondary. After a community reaches its peak, the number of organismsis controlled according to the distributionof the resources.There are many factors,which control the population of a community.Tolerance and limiting such factorsplay a major role in the survival of organisms.

Answer to Problem 1NV

The given blanks can be filled as follows:

S. no.	Correct term
1	Community
2	Limiting factor
3	Tolerance
4	Ecological succession
5	Primary succession
6	Climax community
7	Secondary succession

Explanation of Solution

In an ecological setting, there are many species.The members of a species make up the population and different populations make up a community. A community includes all the living organisms present in each geographical area. It includes all animals, plants, fungi, and other microbes.

A population is influenced by many factors, which include both biotic and abiotic factors. The factors that limit the growth of a population after a certain number are known as limiting factors. All the organisms adapt to their environment and depending on the environmental conditions, they can survive only if the factors are present in that specific range. This rangein which organisms can easily survive and reproduce is known as the tolerance zone. For example, freshwater fishes are adapted to low salinity and they cannot survive in the sea because ofhigh concentration of salts.

In order to survive in new environmental conditions, organisms have to adapt. So, when environmental conditions change, organisms develop certain characters, which can counter the changes. This leads to replacement of the adapted organisms with the older ones and this replacement of old organisms with the new type of organisms is called ecological succession.

Ecological succession that takes place in a region where no life has existed in the past is known as a primary succession, such as the growth of a biological community on a bare rock. As time passes, the community becomes rich in different kinds of species, leading to establishment of a climax community, which is mature and stable.

In case, a community is destroyed by a disturbing agent, such as fire or landslide, then another ecological succession will take place. As in this case,there will be secondary succession where the vegetation was present before, and it would also lead to restoration of the climax community over time.