Question

Q5. Define the ecology terms: biotic, abiotic, community, population, and ecosystem. Explain how they are all related.

Q6. Explain how the concepts of evolution and natural selection are related.

Q7. List and briefly describe each of the stages of mitosis and meiosis in their proper order.

Q8. List and describe the four groups of organic molecules associated with living things.

Q9. Explain how organisms are named and classified by scientists.

Answer 1

Ans.5

Biotic - anything that is living or has ever been living. for example organisms, organic molecules, and cells are biotic components.

Abiotic- the non-living physical or chemical component of ecosystem. for example precipitation, sunlight, minerals, temperature, soil, rocks, temperature.

Community- an interacting group of two or more species occupying the same geographical area.

Population- a population can be defined as a group of individuals of the same species inhabiting the same area.

Ecosystem- An ecosystem includes living organisms and nonliving components such as air, water, and mineral soil etc interacting to produce a stable system in which the exchange of materials between the living and nonliving componenets follows closed paths.

All these terms are related as they are smaller units of classification which ultimately made up an ecosystem.

Ans.6

Natural selection is the mechanism or process through which evolution occurs. it is is the driving force for the evolution, in which heritable traits that help organisms survive and reproduce better become more common in the population over time. this differential selection of certain traits or genes and elimination of others over a large time period leads to speciation (formation of new species) which we term as evolution.

Ans.7

Stages of Mitosis -

Interphase- DNA duplicates

Prophase - Chromatin condensation, mitotic spindle forms

Metaphase - The pairs of condensed chromosomes line up along the equator of the elongated cell.

Anaphase - sister chromatids seperate

Telophase - nuclear envelope reforms

Cytokinesis - separation of two daughter cells

Stages of meiosis -

prophase I - the chromosomes condense, and the nuclear envelope breaks down. crossing- over occurs.

Metaphase I - pairs of homologous chromosomes move to the equator of the cell.

Anaphase I - homologous chromosomes move to opposite poles of the cell.

Telophase I and Cytokinesis - Chromosomes gather at the poles of the cells. The cytoplasm divides.

Prophase II - A new spindle forms around the chromosomes.

Metaphase II - chromosomes line up at the equator

Anaphase II - centromeres divides. Chromatids move to oppisite poles of the cell

Telophase II and Cytokinesis - A nuclear envelope forms around each set of chromosomes. The cytoplasm divides

Ans. 8

The four groups of organic molecules associated with living things are carbohydrates, proteins, lipids and nucleic acids.

Ans. 9

Organisms are classified based on some characteristic features into kingdom, phylum, class, order, family and genus. the name given to the organism has two components i.e., genus and specific epithet. this is called as binomial nomenclature.