1.heredity and Evolution

1.
Heredity and Evolution

Heredity
Heredity is the transfer of biological characters from one generation to another via genes.
Gregor Johann Mendel

1. _______________________________is pioneer of the modern genetics.
Transcription, Translation and Translocation
➢ Proteins are synthesized by DNA through the RNA. This is called as ‘Central Dogma’
Transcription
➢ The process of synthesis of mRNA from DNA is
known as Transcription.
➢ The code for each amino acid consists of three
nucleotides. It is called as ‘triplet codon’.
➢ Dr Har Govind Khorana, a scientist of Indian origin has

made an important contribution in discovery of triplet
codons for 20 amino acids and has been awarded with
the nobel prize in 1968
Translation
➢ As per the message on mRNA, amino acids are
supplied by the tRNA. This is called as ‘translation’
Translocation
The ribosome keeps on moving from one end of mRNA
to other end by the distance of one triplet codon. This is
called as ‘translocation’
Mutation
➢ Any nucleotide of the gene changes its position that
causes a minor change which is nothing but the ‘mutation’.
➢ Example :- Mutation may cause the genetic disorders like

sickle cell anaemia
Evolution
Evolution is the gradual change occurring in living organisms over a long duration
EVIDENCES OF EVOLUTION
1. Morphological Evidences
2.Anatomical Evidences
3.Vestigal Oragns
EVIDENCES OF EVOLUTION EVIDENCES OF EVOLUTION
4.Palaeontological Evidences
5.Connecting Link
6.Embryological Evidences Main Vishal Aur Pradeep
EVIDENCES OF EVOLUTION Computer Engineer
1. Morphological Evidences :-
➢ Various similarities like structure of mouth, position of

eyes, structure of nostrils and ear pinnae and thickly
distributed hairs on body are seen in animals.
➢ Whereas similarities in characters like leaf shape, leaf

venation, leaf petiole, etc. occur in case of plants.
➢ This indicates that there are some similarities in those

groups and hence it proves that their origin must be
same and must have common ancestors
2. Anatomical Evidences
➢ Similarity in structure of bones and joints in organs of

each of those animals.
➢ This similarity indicates that those animals may have
common ancestor
3.Vestigal Organs
➢ Degenerated or underdeveloped useless organs of organisms are called as

vestigial organs.
➢ Same structure under different situation may become useless or even
harmful. Such structure begins to degenerate under such situation as per
the principle of natural selection. It takes thousands of years for a structure
to disappear.
➢ Appendix, which is useless to human, is useful and fully functional organ in
ruminants
4. Palaeontological Evidences
➢ Remnants and impressions of such organisms remain preserved

underground. These are called as fossils
Carbon Dating
➢ Carbon consumption of animals and plants stops after death and
since then, only the decaying process of C-14 occurs
continuously.
➢ In case of dead bodies of plants and animals, instead of
remaining constant, the ratio between C-14 and C-12 changes
continuously as C-12 is non-radioactive.
➢ The time passed since the death of a plant or animal can be
calculated by measuring the radioactivity of C-14 and ratio of C-14
to C-12 present in their body. This is ‘carbon dating’ method.
5.Connecting Link :-
➢ Some plants or animals that show morphological characters by which they can be related to
two different groups of organisms is known as connecting link.
➢ Peripatus :- Connecting link between two different groups – annelida and athropoda.
➢ Duck – billed platypus :- It is a connecting link between mammals and reptiles.
➢ Lungfishes : - It is a connecting link between fish and amphibians.
6. Embryological Evidences:
Darwin’s Theory of Natural Selection
Darwin had published a book titled ‘Origin of Species’
1.Darwin says that all the organisms reproduce prolifically

2.All the organisms compete with each other in a life – threatening manner
3.In this competition, only those organisms sustain which show the modifications essential for winning the competition.
4. Sustaining and selected organisms can perform reproduction and thereby give rise to the new species with their own
specific characters
Objections
1. Natural selection is not the only factor responsible for evolution.

2. Darwin did not mention any explanation about useful and useless modifications.
3. There is no explanation about slow changes and abrupt changes.
Lamarckism
➢ The theory of inheritance of acquired characters from one generation to another is known as
Lamarckism.
➢ It is given by Jean – Baptise Lamarck.
➢ The Concept was based on the principle of use and disuse of organs .
➢ Morphological changes may occur gradually,either due to specific activities or laziness of a
particular organism
➢ Example :- Browsing on leaves of all plants caused the neck of the giraffe to become long.
Objection
➢ Modifications brought in us are not transferred to next generation and thereby Lamarck’s theory was disprove
Speciation
Formation of new species of plants and animals is the effect of evolution. Species is the
group of organisms that can produce fertile individuals through natural reproduction.
Human Evolution
➢ 7 Crore Years Ago - Last Dinosaurs disappeared. Monkey – like animas are Evolved(Modern Lemurs )
➢ 4 Crore Years Ago - Tail of these moneky – like animals Disappeared Egyptopithecus
➢ 2.5 Crore Years Ago - Dryopithecus (Started to live on land )
➢ 1 Crore Years Ago - Ramapithecus (First Rrecord of Human Like animal with us )
➢ 40 Lakh Years Ago - Austrelopithecus (More Intelligent )
➢ 20 Lakh Years Ago - Skilled Human
➢ 15 Lakh Years Ago - Human Walking with erect posture
➢ 1.5 Lakh Years Ago - Neanderthal (1st Example of Wise Man)
➢ 50 Thousand Years Cro –Magnon Man

Ago -
➢ 10 Thousand Years Ago - Agriculture
➢ 05 Thousand Years Ago - Art of writing
➢ 400 Years Ago - Modern Science
➢ 200 Years Ago - Industrial Society

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Heredity and Evolution

Gregor Johann Mendel

➢ Dr Har Govind Khorana, a scientist of Indian origin has

➢ Example :- Mutation may cause the genetic disorders like

➢ Various similarities like structure of mouth, position of

➢ Whereas similarities in characters like leaf shape, leaf

➢ This indicates that there are some similarities in those

➢ Similarity in structure of bones and joints in organs of

➢ Degenerated or underdeveloped useless organs of organisms are called as

➢ Remnants and impressions of such organisms remain preserved

Darwin had published a book titled ‘Origin of Species’

1.Darwin says that all the organisms reproduce prolifically

1. Natural selection is not the only factor responsible for evolution.

➢ 2.5 Crore Years Ago - Dryopithecus (Started to live on land )

➢ 40 Lakh Years Ago - Austrelopithecus (More Intelligent )

➢ 20 Lakh Years Ago - Skilled Human

➢ 15 Lakh Years Ago - Human Walking with erect posture

➢ 1.5 Lakh Years Ago - Neanderthal (1st Example of Wise Man)

➢ 50 Thousand Years Cro –Magnon Man

➢ 200 Years Ago - Industrial Society

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