NET, IAS, State-SET (KSET, WBSET, MPSET, etc.), GATE, CUET, Olympiads etc.: Revision Terminology Part 8
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- Recapitulation theory:- Biogenetic law by Haeckel – Ontogeny repeats phylogeny
- Age of fossil – C14 – dating & amount of pb in rocks.
- Charles Darwin (Birth 1804) survey in HMS beagle vie west Chile, Galapagos island, New Zealand, Tasmania, South Africa and returned in 1836 to S. America (falmouth) & Stayed in gala pages island for 5 year
- Neo-Darwinism:-
(1) Genetic variability
(2) Natural selection – differential reproduction
(3) Reproductive isolation
- J Lederberg – Replica plate technology – demonstration process of selection of antibiotic resistant strains of bacteria
- Heterozygous Sickle cell individuals can fight malaria better than normal man Glucose 6 phosphate dehydrogenase deficiency is common in Negroids. – Hb is denatured & deposited on cell member, if they beans Hb destroyed. = FAVISM due to premature death of RBS such person malarial life cycle is not completed & Protected from malaria.
- Speciation = formation of new species – gradual
- Speciation = formation of new species – rapid – by polyploidy
- Gene freq.
X AA N (total of individual) = X + Y + Z
Y Aa Number of alleles = 2XN
- Ratio of A alleles in population (p) = = Or
- Ratio of a alleles in population (r) = =
- 1st chemical mutagen = mustard gas (sulpher mustard)
- HNO2 & alkylating agent like mustard gas are mutagens to both replicating & non replicas DNA
- Mutagens only to replicating
(1) acridine dye – like proflavin bound to DNA
(2) Bass analogs – 5 – Bromouracil, 2- aminopurine
- Genetic drift – in small population – Cause change in allele frequency when few Indi duals colonize a new habitat or when population greatly reduced due to a natural crash
- Gene flow – transfer of alleles between the population
- Cladogenesis (Divergent evolution) –
- Convergent evolution – 2 different ancestors give rise to organism with similar physical & functional Character just as they are adapted to same environment
- E. g. , Euphorbia & cacti belong to difference families but adopted to same climate.
- Coevolution – in nature species frequently interact so closely that evolutionary changes in one causes evolutionary adjustment in others – Flowering plant – insect pollinator predator – prey relation
- Founder effect - species Type of genetic drift influencing genetic makeup of some population separating from the man population – fare less genetic variation & has a distinctive make up.
- E. g. , Dunbar՚s of eastern - Pennsylvania migrated from Germany & U. S.in 1st century due to religious reasons they did not marry outside their caste⟋sect so the frequency of genes in 2 are different.
- Bottleneck effect – due to drastic red in number of individuals in a population due to environmental factor e. g. population of cheetah of S & E. Africa reduced, now if provide protection only a part of the original gene pool will be recovered
- Industrial melanism – directional selection on active – changing environment will lead to change in genotype⟋phenotype of population