Question
Write down the three main concepts of the modern synthetic theory.
✓
Answer
The modern synthetic theory gives importance to both mutations and natural selection. The factors involved in Modern synthetic theory can be broadly divided into three main concepts i.e. genetic variation, natural selection, and isolation.
- Genetic variations: They are caused due to various aspects of mutation, recombination, and migration. The change in gene and gene frequencies is known as genetic variation. Genetic variations are caused by factors such as - Gene mutation, genetic recombination, gene flow, genetic drift, chromosomal aberrations.
- Natural selection: Natural selection is the process by which better-adapted organisms grow and produce more number of offsprings in the population. It is the main driving force behind evolution. It states that the fittest organism will get selected by nature and produce more offsprings than organisms that did no adapt to the as per the conditions. It brings about evolutionary changes by favoring differential reproduction of genes that bring about changes in gene frequency from one generation to another. Natural selection invariably encourages those genes that assure the highest degree of adaptive efficiency between a population and its environment.
- Isolation: It is the separation of the population of a particular species into smaller units that prevents interbreeding between them. A barrier that prevents gene flow or exchange of genes between isolated populations, is called isolating mechanism. A number of isolating mechanisms are operated in nature and therefore divergence and speciation may occur. The isolating mechanisms are of two types namely, geographical isolation and reproductive isolation.
Need a full question paper?
Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.
Explore more
Similar questions
A plant with red flowers was crossed with another plant with yellow flowers. If $F_1$ showed all flowers orange in colour, explain the inheritance.
→Gene A, B, C and D are linked. By carrying breeding experiment and recording offspring phenotype the following cross over frequencies are determined.
What is the order of the genes on the linkage map?
What is the order of the genes on the linkage map?
Is it possible to consider vegetative propagation observed in certain plants like Bryophyllum, water hyacinth, ginger etc., as a type of asexual reproduction? Give two/ three reasons.
- List the three stages the annuals and biennial angiosperms have to pass through during their life cycle.
- List and describe any two vegetative propagules in flowering plants.
On a visit to a Hill station, one of your friend suddenly became unwell and felt uneasy.
- List two symptoms you would look for to term it to be due to allergy.
- Explain the response of the body to an allergen.
- Name two drugs that can be recommended for immediate relief.
Blood clotting/Coagulation of blood.
OR
Explain blood clotting in short.
OR
Explain blood clotting in short.
Explain the basis on which the gel electrophoresis technique works. Write any two ways the products obtained through this technique can be utilised.
Describe sex-determination in birds with example.
What is mineral nutrition of plants?
Mrs. Peter and Mrs. James had babies at the same hospital. Mrs. Peter took home a girl, Nancy and Mrs. James received a boy, Richard. However, Mrs. James was certain she gave birth to a girl and brought suit against the hospital. Blood tests showed that Mr. James was type O, Mrs. James was type AB and Mr. and Mrs. Peter were both type B. Nancy was type A and Richard was type O. List the possible genotypes of each individual and then indicate the correct parents for each child.
Genotypes :
Genotypes :
- Mrs. Peter ____________.
- Mr. Peter ______________.
- Nancy _____________.
- Mrs. James _________________.
- Mr. James ________________.
- Richard _______________.
- Whose baby is Nancy?
- Whose baby is Richard?