1. Describe the components of an ecosystem.
2. A diploid organism is heterozygous for 4 loci, how many types of gametes can be produced?
3. What is pedigree analysis? Suggest how such an analysis, can be useful.
Answers
1. Every ecosystem is made up of three broad components: producers, consumers and decomposers.
2. the diploid organism will produce 16 different gametes
3. Pedigree analysis is a record of occurrence of a trait in several generations of a family. It is based on the fact that certain characteristic features are heritable in a family, for example, eye colour, skin colour, hair form and colour, and other facial characteristics.
1. Describe the components of an ecosystem.
An ecosystem is defined as an interacting unit that includes both the biological community as well as the non-living components of an area. The living and the non-living components of an ecosystem interact amongst themselves and function as a unit, which gets evident during the processes of nutrient cycling, energy flow, decomposition, and productivity. There are many ecosystems such as ponds, forests, grasslands, etc.
The two components of an ecosystem are:
(a) Biotic component: It is the living component of an ecosystem that includes biotic factors such as producers, consumers, decomposers, etc.Producers include plants and algae. They contain chlorophyll pigment, which helps them carry out the process of photosynthesis in the presence of light. Thus, they are also called converters or transducers. Consumers or heterotrophs are organisms that are directly (primary consumers) or indirectly (secondary and tertiary consumers) dependent on producers for their food.
Decomposers include micro-organisms such as bacteria and fungi. They form the largest population in a food chain and obtain nutrients by breaking down the remains of dead plants and animals.
(b) Abiotic component: They are the non-living components of an ecosystem such as light, temperature, water, soil, air, inorganic nutrients, etc.
2. A diploid organism is heterozygous for 4 loci, how many types of gametes can be produced?
Locus is a fixed position on a chromosome, which is occupied by a single or more genes. Heterozygous organisms contain different alleles for an allelic pair. Hence, a diploid organism, which is heterozygous at four loci, will have four different contrasting characters at four different loci.
For example, if an organism is heterozygous at four loci with four characters, say Aa, Bb, Cc, Dd, then during meiosis, it will segregate to form 8 separate gametes.
If the genes are not linked, then the diploid organism will produce 16 different gametes. However, if the genes are linked, the gametes will reduce their number as the genes might be linked and the linked genes will be inherited together during the process of meiosis.
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3. What is pedigree analysis? Suggest how such an analysis, can be useful.
Pedigree analysis is a record of occurrence of a colour, hair form and colour, and other facial characteristics. Along with these features, there are other genetic disorders such as Mendelian disorders that are inherited in a family, generation after generation. Hence, by using pedigree analysis inheritance of a trait is represented as a tree, trait in several generations of a family. It is based on the fact that certain characteristic features are heritable in a family, for example, eye colour, skin for the study of specific traits or disorders, generation after generation, it is possible to trace the pattern of inheritance. In this analysis, the called family tree. Genetic counselors use pedigree chart for analysis of various traits and diseases in a family and predict their inheritance patterns. It is useful in preventing hemophilia, sickle cell anemia, and other genetic disorders in the future generations.
