Phylum Arthropoda Flashcards
What are the four subphyla of phylum arthropoda?
- Subphylum Chelicerata
- Subphylum Crustacea
- Subphylum Hexapoda
- Subphylum Myriapoda
What are the two main groups of Subphylum Chelicerata?
- Class Merostomata (horseshoe crabs)
- Class Arachnida
Class pcynogonida is also a thing (sea spiders).
What are the characteristics of the arthropods?
- Triploblastic, bilateral, metamerically segmented protostome coelomates.
- Coelum; main body cavity is a haemocoel derived from blastocoel.
- Low pressure, open blood circulatory system.
- Body divided into tagmata
- Exoskeleton and jointed appendages. Growth involves ecdysis (moulting).
- Paired excretory glands and/or malphigian tubules.
To where is the coelum reduced?
Coelum often reduced to around heart.
What are malphigian tubules?
Excretory organs.
Thin, elastic blind tubules attatched to juncture of midgut and hindgut. Free ends in haemocoel.
Malphigian tubules are used to separate out water, Na, K which leave system through tubules before uric acid into intestinal system in hindgut, absorbed back out, then excrete uric acid and faeces.
What are biramous appendages?
- Branched appendages. May be very specialised.
What are the two layers of cuticle?
Cuticle: non-cellular organic layer secreted by epidermis. Two layers are:
- Epicuticle: protein and often waxes
- Procuticle: two layers, both of chitin (nitrogenous polysaccharide) and proteins to form a complex glycoprotein.
- Outer harder exocuticle
- Inner softer softer endocuticle.
What are seta?
Seta are hairs that protrude through cuticle and may contain sensory structures.
What are seta?
Seta are hairs that protrude through cuticle and may contain sensory structures + be connected to a nerve cell.
What are antennal glands?
Antennal glands are kidney-type organs responsible for excretion.
What are antennal glands?
Antennal glands are kidney-type organs responsible for excretion.
Maxillary glands often the same thing but in a different location.
What are the major tagmata?
- Head
- Thorax
- Abdomen
Head and one or more other tagmata may be fused into cephalothorax
What is a prosoma?
A prosoma is a fused head and thorax
What is an opithgoma?
An opithgoma is an enlarged abdomen.
How are muscles arranged?
Muscles are arranged in antagonistic groups: flexors and extensors.
