INTRODUCTION:- Hello, everyone how are you! Let us continue the revolution with this article on evidences of evolution by providing free online education and give a hand to our digital India.

As, you all know that from this platform we are trying to provide free notes of chemistry, physics and biology.

So, let’s begin, in today’s article of evidences of evolution, we will discuss about evidences of evolution which are present between us.

You me and every living being have gone through evolutionary phases and still we are facing evolution but the results of evolution is very slow that’s why we don’t have to face any drastic change related to evolution which can affect our lifestyles.

Evidences of evolution from morphology and anatomy

NOTE:- In this article of evidences of evolution, first we will consider evidences of divergent evolution it contains 2 types, one is homologous organs and other one is analogous organ.

A). Homologous organ:- The organs having same origin and anatomy, functionally they may be similar or dissimilar.

For examples-

*Fore limb of reptiles, birds, mammals(pentadactyle)

*Hind limb of Amphibia, reptiles, birds, mammals.

*Mouth pair of insects

*Thorn of Baugainvellia and Tendrils of cucurbita (originates from axillary bud).

Serial homology- 

Homology between forelimb and hind limb bones.

  • Femur – Humerus
  • Tibio-fibula – Radius-ulna
  • Tarsals – Carpals
  • Metatarsals – Metacarpals
  • Phalanges – Phalanges

Molecula homology-

Evidence of common origin on the basis of similarity in biomolecule.

For example ; Blood protein of chimpanzees and humans are more than 99% similar.

Evidence for origin of diverse group of organism from common ancestor i.e. divergent evolution.

B). Analogous organ/homoplastic organ:

examples- *Sweet potato(root) and potato(stem) = food storage

* Flipper of penguin and dolphin

*wings of birds(feather;epidermis, ectodermal) and wings of bat(ecto mesoderm)

* wings of birds/bat and insects.

* sting of scorpion(modified abdominal appendages) and honey bee(modified Ovi positor).

* fin of sharks and flipper of whale.

* eye of octopus and eye of mammals.

NOTE:- Now we will consider evidences of divergent evolution and it contains 3 types here, these are vestigial organ, atavism and connecting link/missing link.

So, lets start.

C). Vestigial organ- Non-functional organ is present generation may be functional in their ancestors and related organism.

these are evidences for divergent evolution.

For examples-

#Human vestigial organ;

* Canine(more priority than molar but not third molar)

* Third molar (more priority than canine)

* Panniculus carnosis (subcutaneous muscle)

* Plica semilunaris (nictitating membrane)

* Auricular muscle (ear pinna muscle)

* Abdominal muscle

* Body hair

* Vermiform appendix

* Scalp hair

* Scalp muscle

* Caecum

* Coccyx

#Plant vestigial organ;

* Staminode

* Pistilode

#Animal vestigial organ;

* Pelvic girdle (phython and whale)

* Hind limb

* Green gland

* Splint digit in horse

D). Atavism-

Appearance of ancenstral trait in new born baby is called atavism

For example-

* baby born with small tail

* baby born with thick hair on body/lion baby

* long canine with respect to incisor

* functional auricular muscle

Next evidence for divergent evolution is …

E). Connecting link/missing link:

This one is also known as fossil connecting link and the example is Archeopterys.

For example-

* Virus is the connecting link between living and non living.

* Euglena is the connecting link between plants and animals.

* Proterospongia(choanolagelates) is the connecting link between protozoa and porifera.

* Peripatus(LF) is the connecting link between arthropoda and annelida.

* Neopilina(LF) is the connecting link between mollusca and annelida.

* Hemichordata is the connecting link between chordata and non chordata.

* Chimaera is the connecting link between osteichthyes and chondrichthyes.

* Dipnoi(lung fish) and coelecanth/latimaria(living fossil) is the connecting link between amphibia and. Osteichthyes

* Sphendon/tuatara(living fossil and third eye functional) and Syemouria(stem reptile fossil) is the connecting link between reptilia and amphibia.

* Archeopteryx(bird fossil) is the connecting link between birds and mammals.

* Prottheria/Monotremate(reptile like animal) and fossil of synapsida, pelycosaur and therapsio is the connecting link between mammals and reptilia.

# Among homologous, vestigial, homologous and analogous and homologous and vestigial. Homologous and Vestigial are the evidences for organic evolution because actual evolution are divergent evolutions.

Conclusion of evidences of evolution:

So, here we come to the conclusion of this topic.

Now, let me know what you all learned from this above article and your advices for further articles are welcome. Keep studying smartly and focus on knowledge.

Keep smiling.

 

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