ARTHROPODS: THE FIRST

ANIMALS TO HAVE JOINTED APPENDAGES

What is an Arthropod?

ARTHROPODS: THE FIRST ANIMALS TO HAVE JOINTED APPENDAGES Over the course of animal evolution, a

number of changes in the coelomate body plan led to the evolution of animals with even greater complexity.

ARTHROPODS: THE FIRST ANIMALS TO HAVE JOINTED APPENDAGES The first major change in the coelomate

body plan to arise was segmentation. Segmentation provided animal bodies with greater flexibility.

ARTHROPODS: THE FIRST ANIMALS TO HAVE JOINTED APPENDAGES Segmentation provided animal bodies

with greater flexibility. It also enabled individual segments to

have individual functions.

Guts & Reproduction

Sensory Muscles

ARTHROPODS: THE FIRST ANIMALS TO HAVE JOINTED APPENDAGES The first segmented animals to evolve

were the annelid worms, such as earthworms and leeches.

All coelomate animals except mollusks and echinoderms are segmented.

ARTHROPODS: THE FIRST ANIMALS TO HAVE JOINTED APPENDAGES Biologists say that segmentation

underlies the body organization of all advanced coelomate animals.

A second major change in the evolution of the coelomate animal body was the evolution of jointed appendages.

ARTHROPODS: THE FIRST ANIMALS TO HAVE JOINTED APPENDAGES Arthropods were the first animals to

have jointed appendages. Arthropods use jointed appendages as legs for walking, wings for flying, antennae to sense their environment, and as mouthparts for sucking, ripping, and chewing their food.

ARTHROPODS: THE FIRST ANIMALS TO HAVE JOINTED APPENDAGES Jointed appendages have proven to be

very successful in the animal kingdom – more than half of all named animal species on Earth are arthropods, most of which are insects.