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.

THANK YOU