Q.No 5
Write a note on population of organisms and their interaction.
Answer: POPULATION:
DEFINITION: A population is a group of organism of the same species located in the same place at the same time.
Examples are the number of rats in the sewerage of a city, or the number of students in your biology class. On a larger scale all the people of the world constitute the population.
INTERACTION BETWEEN ORGANISMS:
The term population and species are interrelated because a species is a population. The term population is, however, often used for portions of a species by specifying a space and time. For example, the size of the human population in a city changes from hour to hour and also varies according to boundaries of the city you set.
ATTRIBUTES OF POPULATION:
Population is higher level of biological organization than organism (whole) because here a group of organism of the same species are involved. This level of organization has its own attributes, which come into being by living of a group of organism of the same species together. Some of these attributes are gene frequency, gene flow, age distribution, population density, population pressure etc. All these are new parameters, which have appeared due to population of an organism. You will study about them in detail in population ecology. Populations of different species (plants and animals) living in a habitat form a community. One of the consequences of biodiversity is that many different organisms live in the same area and they interact with each other.
Q.No 6
Define community How different combinations of populations remain stable in the commnity.
Answer:
COMMUNITY:
Populations of different species (plants and animals) living in a habitat form a community.
INTERACTION OF ORGANISMS IN A COMMUNITY: One of the ways that organisms interact is by feeding one another. Different organisms belong to the different trophic levels i.e., producer and consumer (herbivores, carnivores). A community includes many different food chains. Some organism may be involved in several of the food chains at the same time, so that food chain become interwoven into a food web. Some communities are complex and well interrelated other communities may be simple. In a simple community any change can have drastic and long lasting effects.
STABILITY IN A COMMUNITY: In a community, the interacting food chains usually result in a relatively stable combination of populations so that if a particular kind of organism is removed from a community, some adjustment usually occurs in the population of other organisms with in the community. For example, the indiscriminate use of insecticide by man to control the pest actually increase the insect problem because insecticides kill many beneficial predator insects rather than just the target species thus increasing the population of herbivore insects.
BALANCE IN A COMMUNITY: Communities are dynamic collection of organism, as one population increase, another decrease Usually populations fluctuate an abiotic factors change and a change in the size of one population will result in the changes in other populations.
Q.No 7
Describe the distribution of living organisms in space.
Answer:
LIVING WORLD IN SPACE:
The organism's interaction can take many shapes. It may be predation, parasitism, commensalism, mutualism and competition. Living world of today is enormous in size. It has been reproducing and evolving since the time of its origin on this planet. Today almost all parts of the world abounds in living organisms. The distribution of organism in space can be studied through biomes. A biome is a large regional community primarily determined by climate. It has been found that the major type of plant determines the other kind of plants and animals. These biomes have therefore been named after the type of major plants or major feature of the ecosystem.
Q.No. 8
Describe the distribution of living organisms in time.
Answer:
LIVING WORLD IN TIME:
Sınce the time of origin of life on this planet, various organisms were evolved and dominated this planet during various time of geological time chart. The evidence obtained from the discovery and study of fossils, which allows biologists to place organisms in a time sequence, has found this. As geological time passes and new layers of sediments are laid down, the older organisms should be in deeper layer, provided the sequence of the layers has not bees disturbed. In addition it is possible to date/age rocks by comparing the amounts of certain radioactive isotopes they contain. The older sediment layers have less of these specific radioactive isotopes than the younger layers. A comparison of the layers gives an indication of the relative age of the fossils found in the rocks. Therefore the forests found in the same layer must have been alive during the same
Q.No 9.
Discuss briefly phyletic lineage in biological organization.
Answer:
Total Number of Species:
There are nearly 1.500,000 species of organism, currently known to science More than half of these are insect (53.1 %) and another 17.6 % (2,50,000) are vascular plants. Animals other than insect are 19.9% (281.000 species) and 9.4 % are fungi, algae, protozoa, and various other prokaryotes.
This list is far from being complete, Various careful estimates put the total number of species between 5 and 30 millions. Out of there only 1.5 million species have been identified so far.
Evolution:
The life of today has come into existence through phyletic lineages of the organism living in the remote past. Evolutionary change often produces new species and then increases biodiversity. There are different theories related to evolution . The process of evolution takes much times i.e very slow process.
Phyletic Lineage:
A phyletic lineage is an unbroken series of species arranged in ancestor to descendant sequence with each later species having evolved from one that immediately preceded it. If we had a complete record of the history of life on this planet, every lineage would extend back in time to the common origin of all early life. We lack that record because many soft bodied organisms of the past had not left their preserved record as fossils.
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