Introduction to Comparative Vertebrate Anatomy

Comparative Vertebrate Anatomy Definition

The study of vertebrate structures, functions, development, and evolution through

comparison.

Phylogeny

The study of evolutionary relationships and ancestry among vertebrates.

Homology

Similarity of structures due to a shared evolutionary ancestor.

Analogy

Similarity of function in structures with different evolutionary origins

Homoplasy

Similar traits that evolved independently in different species.

Form and Function

The relationship between a structure’s shape and its function

Evolution

The gradual change of vertebrate species over time.

Vestigial or Rudimentary Structures

Reduced structures that remain from ancestral forms

Ontogeny

The development of an organism from embryo to adulthood.

Heterochrony

Changes in the timing of developmental processes.

ANATOMY AND MORPHOLOGY

What are the Structural Aspects of Vertebrates

Anatomy

is the study of the body parts of an

organism and how they are arranged.

Morphology

is the study of the shape, form, and

structure of body parts

1. Notochord

2. Dorsal hollow nerve cord

3. Pharyngeal slits

4. Post- anal tail

1. What are the 4 Anatomy of Vertebrates

• Notochord

• A soft, rod-like part inside the body.

• It supports the body and helps it keep its shape.

• It later becomes the backbone in many animals

Dorsal Hollow Nerve Cord

• A long, hollow tube found along the back.

• It connects the brain to the rest of the body

• It sends messages to different parts of the body.

• It controls movement and body actions.

Pharyngeal Slits

• Small openings in the throat area.

• They help some animals breathe in water.

• In humans, they develop into parts of the ear and throat.

Post-Anal Tail

• A tail located after the anus.

• It helps with movement and balance.

• Some animals keep it, while others lose it as they grow.

Vertebral Column/Backbone

• Centrum

• Neural Arch

The Morphology of Vertebrates

Vertebral column or backbone

• surrounds and protects the spinal cord.

• Made of a series of bones called vertebra or vertebrae.

1. Centrum

2. Neural Arch

1. Two main parts of vertebrae

Centrum

structural support and weight-bearing capacity.

Neural arch

attachment site for muscles and ligaments involved in movement and posture.

Phylogeny

study of evolutionary relationships/history of a group or structure.

1. Paleontology

2. Functional Adaptation or Comparative Morphology

3. Embryology

3 Ways to Study Phylogeny

PALEONTOLOGY

• The study of the fossil record of the history of animals with backbones and is termed Vertebrate Paleontology.

FUNCTIONAL ADAPTATION

•A functional adaptation includes the evolutionary modification or changes in the body and how the body works that help an organism survive and reproduce in their environment.

EMBRYOLOGY

• is the study of how embryos grow, from the moment of fertilization until basic body parts and organs form. It helps us understand how genes and the environment affect the growth and development of an organism.

1. Ectoderm

2. Mesoderm

3. Endoderm

What are the 3 Germ Layers in Embryology

Ectoderm

• outermost germ layer

• Epidermis, nerves, hair, nails, nervous system.

Mesoderm

• middle germ layer

• Skeletal system, muscles, gonads, connective tissues, circulatory system (heart and blood vessels), reproductive organs, kidneys, and the dermis of the skin.

Endoderm

• innermost germ layer

• Lining of digestive and respiratory tracts, & other organs such as liver, pancreas, and the lining of the urinary bladder

1. Fertilization

2. Cleavage

3. Blastulation

4. Gastrulation

What are the 4 patterns of development that all vertebrate embryos undergo to?

Homology

• is the similarity of structures because of similar embryonic origin and development. This is considered strong evidence of common descent.

Homologous structures

• are actual physical structures that show this similarity.

• Same structure, same origin, different function

Analogy

• is the similarity of function and superficial resemblance of structures that have different origins/ ancestor.

Analogous structures

• are the actual body parts that look or act alike because they perform the same function, even though their embryonic origin is different.

• Same structure, same function, different origin.