HOMOLOGY AND ANALOGY DR.PIYUSH KUMAR RAI DEPARTMENT OF BOTANY - PowerPoint PPT Presentation

HOMOLOGY AND ANALOGY DR.PIYUSH KUMAR RAI DEPARTMENT OF BOTANY SEMESTER- IV PAPER - BOT CC410 PATNA WOMEN’S COLLEGE PATNA UNIVERSITY, PATNA

HOMOLOGY ( HOMO- SAME , LOGOUS – ORIGIN Richard owen (1804-1892) Introduced the term homology - The origin with some structural design and origin but function are different are called homology organ . - Homologous structure as a result of divergent evolution.

• Homology indicates common ancestor. • Due to different need , some structural developed differently this is called divergent isolation .

HOMOLOGY IN PLANTS • Plants too have Homologous structure like those seen in animals like Pitcher , venustrap , Poinsettia and Cactus , the leaves show different function and shape from the normal leaves. • Each leaves is a Homologous structure derived from a common ancestral form .

EXAMPLES: • Forlimb of mammals • Legs of vertebrate • Mouth part of insect • Homology is also seen in the Skeleton , healthy blood vessels .

EXAMPLES

ANALOGY ( ANA – DIFFERENT, LOGOUS – ORIGIN) • The organ which have similar function but different in their structure detail and origin are called Analogous Organ. • The Analogous Structure are the result of convergent evolution

• Analogous organ do not show common ancestory but they show evolution. • Due to same function , different evolve similarty this is called convergent evolution.

EXAMPLES:

EXAMPLES: • Dog fish and Whale • Hands of Man and Trunk of Elephants • Wings of Butterflies and Mammals • Sweet Potato ( root modification) and Potato ( stem modification ) • Eyes of octopus and Mammals.

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