Question

5. Differentiate between the processes and results of microevolution and macroevolution, and explain how these contribute to speciation. • Explain why individuals do not evolve? At what level does evolution occur? • What are gene pools? Describe microevolution. • What is macroevolution including speciation? What are novel features?

6. Relate the geologic history of the planet to evolutionary history, including mass extinctions and subsequent diversification. • What is the role of mass extinctions and diversification in macroevolution? • How does the geologic record, plate tectonics, and Pangea support the evolution of life?

7. Define a species and describe the barriers that help maintain species. • What is a species? What are reproductive barriers? How do these barriers help maintain the various species?

8. Describe how scientists classify organisms and construct phylogenies to represent how organisms are related. • What is taxonomy and the three-domain system? • How do phylogenic trees represent hypotheses about evolutionary history?

Answer 1

Ans.5)

• Microevolution deals with change in the gene pool of a single population while macroevolition considers the broad pattern of evolutionary change over long periods of time and includes the origin of new groups.
• As there are changes in gene pool in microevolution,it lead to few change in same species called intra-species genetic change while the macro evolution lead to change in species
• individuals don't involve, they retain the same genes throughout their life. When a population is evolving ,the ratio of different genetic types is changing - each individual organism within a population doesn't change.
• Evolution occurs at genetic level as organisms gene mutate or recombine in different ways during reproduction and are passed on to future generations.
• Gene pool - the collection of all the genes and the various alternate or allelic forms of those genes within a population is called gene pool.
• Microevolution- microevolution are the changes in allele frequency that can be observed within a population. Microevolution occur by --

1. Gene flow - it is the transfer of alleles from one population to another.
2. Genetic drift- it describes the random fluctuations in the frequency of alleles within a population.
3. Mutation - mutation are the ultimate cause of all variation in genetic diversity and the only source of new alleles.
4. Selection - the natural selection of alleles tha control for certain traits occurs when an organism's gene variants give it an adaptive advantage over the other gene variants in a population ,ultimately allowing it to reproduce and increase the frequency of these genes.

• macroevolution- macroevolution is a large scale evolution occurring at the level of species and above. Macroevolution can occur due to accumulation of microevoltionary changes is population or it may occur by allopatric means where two populations are separated by geographical barriers.
• Novel features are modification of existing features for a new function that may occur by -

1. Duplication and divergence
2. De novo i.e., entirely new features
3. Through a variety of intermediate steps.