Phylum Arthropoda Power-point Presentation Slides
- 1. PHYLUM ARTHROPODA The Life of Creepy Crawlies
- 2. AREAS TO BE DISCOVERED Blueprint for success Classification Metamerism & Tagmatization Exoskeleton Metamorphosis
- 3. INTRODUCTION • Arthropoda is the largest phylum with about nine lakh species. • They may be aquatic, terrestrial or even parasitic. • They have jointed appendages and a chitinous exoskeleton. • This phylum includes several large classes and contains the class Insecta which itself represents a major portion of the animal species in the world. They possess the ability to survive in every habitat.
- 5. BLUEPRINT FOR SUCCESS • Almost any way you look at them, arthropods are successful: • They have been around for more than 500 million years and are still evolving. • They live on Earth in overwhelming numbers. • They have come in all shapes and sizes. • They have evolved to fill a variety of ecological niches — from tiny internal parasite to giant bird-eating predator.
- 6. CLASSIFICATION- CRUSTACEA • They are aquatic, terrestrial, or parasitic. • The head is fused with the thorax region known as the cephalothorax. • Respiration occurs through gills or general body surface. • The body is covered by a single large carapace. • They possess two pairs of antennae and five pairs of appendages. • They have a pair of compound eyes and gonopores. • Development is indirect. Larval stage is present. • Eg., Daphnia, Palaemon • The subphylum Crustacea is divided into six classes- Branchiopoda Remipedia Chephlocarida Maxillopoda Ostracoda Malacostraca
- 8. MYRIAPODA • These are mostly terrestrial. • The body is elongated with numerous segments. • The head is provided with antennae, two pairs of jaws, and a pair of simple eyes. • They contain numerous legs. • A pair of mandibles is present inside the mouth. • They respire by trachea and excretion occurs by Malpighian tubules. • Eg., Julus, Scolopendra • The subphylum Myriapoda is divided into the following classes: Chilopoda Diplopoda Pauropoda Symphyla
- 10. HEXAPODA • They are mostly terrestrial. • The body is differentiated into head, thorax, and abdomen. • The thorax is divided into three segments. • The abdomen has 7-11 segments. • They have three pair of appendages. • It has a pair of compound eyes • They respire through gills and trachea. • Malpighian tubules are the excretory organ. • Development is indirect, and the larval stage is present. • Eg., Tabernus, Mosquitoes, Ants. • The subphylum Hexapoda is divided into two classes: Insecta Entognatha
- 12. CHELICERATA • They are mostly found on land. • The body is differentiated into cephalothorax and abdomen. • Antennae are absent. • The abdomen is divided into 13 segments. • It has four pairs of interior appendages. • They respire through trachea or gills. • The Malpighian tubules help in excretion. • Eg., Aramea, Limulus • The subphylum Chelicerata is divided into the following classes: Arachnida Merostomata Pycnogonida
- 14. ONYCOPHORA • These are small- sized, terrestrial arthropods. • The body is divided into segments. • Excretion occurs through nephridia. • They respire through the trachea. • Eg., Paripatus
- 15. TRILOBITOMORPHA • These are primitive arthropods and are extinct. • They were found in abundance during the Paleozoic era. • The body was divided into three lobes- one median and two lateral lobes. • Head bore a pair of compound eyes and a pair of antennae. • There was no structural differentiation of the body parts. • The body was divided into head, thorax and pygidium. • Appendages are biramous. • The subphylum had only one class- Trilobita
- 16. METAMERISM • Metamerism in arthropods refers to the segmentation of the body into a series of repeating, similar body segments known as metameres or somites. This segmentation is a distinctive characteristic of arthropods. • Metamerism of arthropods is most evident externally because the arthropod body is often composed of a series of similar segments, each bearing a pair of appendages. • Internally, however, septa do not divide the body cavity of an arthropod, and most organ systems are not metamerically arranged.
- 17. ADVANTAGES OF METAMERISM • Segment specialization for specific functions • Efficient, coordinated locomotion through independent segment movement • Flexibility and adaptation to diverse environments • Supports development of complex body shapes and sizes • Segmental nervous system enables faster and localized control of movements • Facilitates controlled growth during molting cycles
- 18. TAGMATIZATION • Metamerism permits the specialization of regions of the body for specific functions. This regional specialization is called tagmatization. • In arthropods, body regions, called tagmata are specialized for feeding and sensory perception, locomotion, and visceral functions.
- 19. EXOSKELETON • An external, jointed skeleton, called an exoskeleton or cuticle, encloses arthropods. • It provides structural support and protection. • It provides impermeable surfaces for the prevention of water loss • It provides a system of levers for muscle attachment and movement. • The exoskeleton covers all body surfaces and invaginations of the body wall • It is nonliving. • Secreted by a single layer of epidermal cells.
- 21. METAMORPHOSIS • Reduction of competition between adults and immature stages because of metamorphosis. • Metamorphosis is a radical change in body form and physiology as an immature stage, usually called a larva, becomes an adult. • The evolution of arthropods has resulted in an increasing divergence of body forms, behaviors, and habitats between immature and adult stages. Example: The caterpillar that feeds on leafy vegetation eventually develops into a nectarfeeding adult butterfly or moth.
- 23. OVERVIEW We have discussed: What are arthropods? Blueprint for success Classification Metamerism & Tagmetization Exoskeleton Metamorphosis