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Slide 2 : BBIPL Is evolution
still on ? Dr Subroto Biswas This presentation is brought to you by ….. http://bisbio.in
Slide 3 : How
did the ideas
come upon ?
George Cuvier (1769-1832) : George Cuvier (1769-1832)
Georges Louis Buffon (1707-1788) : Georges Louis Buffon (1707-1788) Who was the first to give evolutionary ideas ?
Jean Baptistc Lamarck (1744-1829) : Jean Baptistc Lamarck (1744-1829)
Slide 7 : Student of Buffon
In the year 1809 (the year of Darwin's birth) gave the first complete explanation of evolution
In his book, Philosphie Zoologique.
Lamarckism : Lamarckism Known as the inheritance acquired characters
Described the means by which the structure of an organism altered over generations
Example of these acquired characters : Example of these acquired characters Legs and neck of giraffe became longer
By browsing on tall trees.
This passed on to their offsprings.
Over many generations they produced the long neck of the modern giraffe.
Lamarck's concept …… Transformational
That is, the individuals transform their appearance to produce evolution.
Lamarck’s Giraffe : Lamarck’s Giraffe Long neck developed over the time
August Weismann : August Weismann Rejected Lamarckism.
Gave ‘Neo-Darwinism'.
Slide 12 : How did snakes
get a long body ?
Slide 13 :
Slide 14 :
Slide 15 : Lamarck explained …..
Ancestors of the Snakes were four limbed
Tried to conceal themselves in the bushes.
This required creeping habit and elongated body.
These efforts resulted into aborted limbs And elongated body of snake.
Slide 16 : How did
the flat fishes
have both eyes
on one side ?
Slide 17 : Possibly ancestors of these fishes used to turn over to one side and made efforts to bring both the eyes on the upper side.
This adaptation was inherited and all the flat fishes now have their eyes on one side.
Slide 18 :
Ducks and other birds wanted to swim ? : Ducks and other birds wanted to swim ?
Slide 20 : Were forced to search food in water.
They spread their toes
Stretched their legs
Waded through the water
Webbed feet !
Slide 21 :
Slide 22 : Why did
Whales and Dolphins
lose their hind limbs ?
Slide 23 :
Slide 24 : Probably due to the disuse of these organs
Slide 25 : Why
Moles
have reduced eyes ?
Slide 26 : Most of the cave animals live underground
Reduced or nonfunctional eyes…disuse.
Do you think this animal can run fast ? : Do you think this animal can run fast ?
Slide 28 : Deer run fast to escape from predators
An example of use ?
Slide 29 : Lamarckian theory
Is
exemplified in hard workers
Slide 30 : Develop callosities on their palm due to their repeated use and hard work.
Slide 31 : But can such
acquired characters
be
transmitted to
Next the generation ?
Slide 32 : Can environment (light)
effect
Ranunculus acquatilis
to produce
large leaves
on the surface ?
In these hydrophytes submerged leaves are not lobed or dissected. On the surface they accumulate light for better photosynthesis.Show subsequent inheritance of acquired character. : In these hydrophytes submerged leaves are not lobed or dissected. On the surface they accumulate light for better photosynthesis.Show subsequent inheritance of acquired character.
Slide 34 :
Slide 35 : Did we lose the function of these due to disuse ? The vestigial organs of man like ear membrane
Slide 36 :
Slide 37 : The vestigial organs of man like coccycx
Slide 38 : The vestigial organs of man like
plica semilunaris (nictitating membrane)
Slide 39 : According to the second principle, environment do effect on organism but it is doubtful if new needs arise due to its influence.
Slide 40 : The third law of use and disuse of organs is true in many cases.
For example a body builder develops strong muscle by constant training.
But can they pass on such characters ?