Download - Comparative Anatomy of the Limb
Comparative Anatomyof the Limb
Presented by Dr. Farhana Taher Sumya
Guided by Dr. Zinnat Ara Yesmin
ObjectivesDefine comparative anatomy
Classifiy the phylum chordata
Discuss the limb development of tetrapods
Describe the features of tetrapods
Objectives (contd...)
Explain the structure and function of the limb of tetrapods
Discuss homology and analogy in relation to the limb of tetrapods
Comparative Anatomy
Kingdom: AnimaliaPhylum:chordata
Group: Craniata
Subphylum:
GnasthostomataSu
perclass: Tetrapoda
Class: Mammalia
Class: Aves
Class: Reptilia
Class: Amphibia
Superclass: Pisces
Subphylum:
Agnatha
Group: Acrania
Classification of phylum chordata
Features of Tetrapods
Paired appendages are limb which are pentadactyl
Sternum present
Lung present
Number of skull bone is reduced
Features of Tetrapods (contd…)
Amphibia (e.g: Frog, toad)Pentadactyl limbs and no nails on claws3 chambered heart and lung present
Reptilia (e.g: turtle, lizard, snake)
Pentadactyl limbs with claws except snake and lizards
3 chambered heart and lung present
Aves(Bird)
Limbs with clawsLung present and no urinary bladder
Mammalia (e.g: cat,dog,monkey,human)
Pentadactyl limbs with claws,nails ,hoof at the end of digit
4 chambered heart and lung present
Features of Tetrapods(contd)
Limb development of tetrapodsLimb bud
Apical ectodermal ridge
Apoptosis
Limb bud
Apical ectodermal ridge
Apoptosis
Structure and function of the forelimb of tetrapods
Amphibia Reptilia
Structure and function of the forelimb of tetrapods (contd….)
Aves Mammalia
Structure and function of forelimb of tetrapods (contd….)
Comparison of primates hand
Structure and function of the hindlimb of tetrapods
Amphibia Reptilia
Structure and function of the hindlimb of tetrapods (Contd.)
Aves Mammalia
Structure and function of the hindlimb of tetrapods (Contd.)
Homology
Homology (contd.)
Analogy
Analogy (contd.)
Homology Analogy
Similar in anatomy
dissimilar in anatomy
Doing dissimilar function
Doing similar function
Homology & Analogy
Homology (contd)
We have probably noticed that our arms are shorter than our legs. However, this is not the case in all species. Many species of monkeys, in particular, have longer arms than legs, or some, like dogs and cats, have four limbs all of similar length. This is because the specific function of those limbs differs from humans. Monkeys do a lot more climbing than walking, while dogs and cats use all four limbs to walk and run.
However, despite small differences in function, they still have one upper arm bone, followed by two lower arm bones, wrist bones and finger bones - just like humans. Although, sometimes the length or number of the bones and the shape of the muscles used to move their arms and legs may vary slightly. But, despite slight variations, the order in which they are put together and the general function of motion are similar to those in humans and other mammals.
Homology
The structure which are similar in their morphology, anatomy, genetics and embryology but dissimilar in their function is called homologous structure. The relationship between the homologous structure is called homology.