Arthropods Flashcards
What is the most succesfful and diverse group of animals?
Arthropods
85% of all species
Most dominate in fossil record
Where can arthropods live
Cosmopolitan (air, land and water)
The body of arthropods is ______ and possess _______
Segmented
Jointed appendages for feeding and movement
Phylum Arthropoda unique characteristics
- Body epidermis is composed of chitonous exoskeleton which is jointed, segmented and hardened/sclerotized
- lack locomotory cilia in larval and adults stages
Important Arthropod groups include:
- Insecta: anta, dragonflies and bees
- crustaceans: crabs, lobsters and shrimp
- arachnids: spiders and scorpians
- myriapods: centipedes and milipedes
Tagmatization
Body divided into segments with specialized functions
Ex: insecta and crustaceans have 3 distinct body segments (head, thorac and abdomen)
Arthropods possess __________ made up of ______ which is shed periodically
Jointed, flexible exoskeleton
Chiton
Reason for success of the members of the phylum
Exoskeleton is secreted by what:
Epidermal cells
In terms of body plan and development, arthropods are ________ and ______
Bilaterally symmetrical and triploblastic
Body organization of arthropods is of an _____ level
Organ-system
4 layers of exoskeleton
- Epicuticle (outer layer)
- Endocuticle (differ among species)
- Epidermis
- Basment membrane
Exoskeleton is similar to shells of molluscs but differ in
Function and composition
In addition to protection, exoskeletong plays a role in
Movement and composition
Sclerotization/ tanning
Hardening of the cuticle by cross-linking of proteins of the epicuticle
Epicuticle
- Waxy, made up of layers of lipoproteins, underlaid by layers of lipids
- water impermeable (resistent to water loss by dehydration)
- disadvantage: can’t function in respiration directly
- thin, composed of 3% of wrthropod exoskeleon
Procuticle
Forms bulk of arthropod exoskeleton
- exocuticle
- endocuticle
Made largely of chitin (polysaccaride) and proteins
Biotechnological application of chiton
-Chiton has unique characteristics of strength, non-allergenic and biodegradable thus, it is applied as follows:
- dissolved and reformed into fibers for fabrics abd surgical sutures
- making capsulated therapeutic drugs
- proposed for yse as plastic wrap for processed foods: alrhough not digestible by vertebrates
- as food additive: reduce calorie and cholesterol uptake
- purifying agent: high binding potential was harnessed for removing organic and inorganic wastes from table water and sewage purification
The major body cavitt of an arthropod is a
Hemocoel forming the circulatory system
The true coelom of arthorpods is
Greatly reduced to the spaces of the genital and excretory organs as it is encased in a rigid exoskeleton
Arthropods have a complete _____ system
Digestive
With mouth and anus
Excretory organs of arthropods
Green glands, malpighan tubules, cocal glands
Nervous system of arthropods
Similar to annelids with a dorsal brain connected with a nerve ring to double ventral nerve cord
Sensroy organs of arthropods
Eyes (simple or compound), chemo-and tactile receptors, balancing and auditory organs
Molting
- process of shedding of exoskeleton and or cuticle lining the inner gut. Also called Ecdysis
- ensures growth and decelopment among arthropods
- involves secretion of new cuticle underneath the old one by underlying epidermal cells, followed by partial enzymatic degrading of old cuticle which is released.
- newly secreted soft cuticle ensures growth of the arthropod prior to hardening