L5 - Arthropods Flashcards
What are the subphylum of arthropoda?
Crustacea, Hexapoda, Myriapoda, Cheliriformes
What is the abundance phylum Arthropoda?
Estimated that there are approximately 1.5 million, 5.5 million, and 7 million species of beetles, insects, and terrestrial arthropods. Crustaceans estimated at over 50k, but as they are mostly aquatic this is almost an underestimate. Between 75-80% of all other animals are arthropods.
What is the phylum Arthropoda?
Bilaterally symmetric, triploblastic protostomes. Each body segment has a pair of segmented, jointed, ventrally attached appendages ; some have evolved into mouthparts. Trend is towards reduction in number of segments. Cephalon (head) usually has a pair of compound eyes. Size - microscopic up to 4m long. Cuticle forms an exoskeleton of plates (sclerites)
What is the phylum Arthropoda? pt 2
No true hydrostatic skeleton, no repeating organs in each segment, no cilia. Seperate sexes (usually), immature stages represented by varying numbers of larval forms. Tagmatisation (tagmosis). Body divided into functional groups of segments called tagma (pl. tagmata). Minimally divided into head (cephalon) and trunk, which is usually subdivided e.g. crustacean trunk divided into peraeon (thorax) and pleon (abdomen)
What is the phylum Arthropoda? What is the Bauplan?
The arthropods are taxonomically joined together by a single body plan, which is the end result of a process known as arthropodisation. Previously, people thought that this body plan evolved independently in each of the subphyla, and that the similarities were due to the presence of an exoskeleton. Current evidence points to a single common ancestor to all the arthropods, and that single common ancestor had an exoskeleton. The arthropod exoskeleton provided good protection from attackers, but is also relatively inflexible and heavy.
What is the phylum Arthropoda? How is the arthropod cuticle hardened and what are some of the consequences?
Hardened by sclerotisation (tanning) - crossbonded protein molecules. In some (e.g. Crustaceans) hardening taken further by mineralisation - depositing of calcium carbonate into outer regions of procuticle.
Consequences
- Very strong and protective against predation & water loss
- Must be in sections to allow movement.
- Restricts growth, therefore have to moult
-Relatively heavy which restricts locomotion on land.
- Unless it is very thin, respiration, excretion and osmoregulation are restricted
- New methods of sensing the external environment are needed
What is the phylum Arthropoda? What does each somite (body segment) have?
A large dorsal sclerite called a tergite (tergum)
A large ventral sclerite called a sternite (sternum)
Side regions are unsclerotised & flexible, called pleura (pleuron) where limbs articulate.
Body cavity is open haemocoel, organs bathed in haemocoelic fluid or blood
What is the phylum Arthropoda? What is the cuticle divided into?
Cuticle is divided into epicuticle and procuticle. Procuticle (layers of protein and chitin) subdivided into exocuticle and endocuticle. Endocuticle can be calcified or uncalcified ; secreted by epidermis. Cement layer : lipoprotein protects against bacteria. Waxy layer : best developed in insects and arachnids ; prevents water loss. These two layers isolate remainder of the cuticle from external environment ; critical in terrestrial arthropods. Remainder called cuticulin layer ; mainly protein.
What is the phylum Arthropoda? What is the arthropod limb joint?
Sclerites are joined at articulation points by thin and flexible cuticle to allow for movement ; called articular membranes. Usually, each articulation is bridged by one or more pairs of antagonistic muscles. Muscles may be attached to inward projections of sclerites called apodemes. There may be points of contact or bearing surfaces between sclerites called condyles
What is the phylum Arthropoda? Growth?
Exoskeleton is rigid so no gradual growth possible. Occurs in steps after shedding exoskeleton ; known as moulting. Controlled by the hormone ecdysone. Moulting is therefore known as ecydsis (final shedding of old cuticle). Intermolt stages known as instars.
What is the phylum Arthropoda? What is the process of moulting?
Enzymes digest old endocuticle, separating exoskeleton from epidermis. Epidermis secretes new, soft cuticle beneath existing exoskeleton. Old cuticle splits along pre-determined lines. Animal takes in air or water and body swells, enlarging the new cuticle. Cuticle then hardened by sclerotisation. All cuticular linings are lost during ecdysis, including surfaces such as foregut, hindgut, eyesurfaces etc. Dangers include difficulty withdrawing from old cuticle, prone to predation before new cuticle hardens
What is the phylum Arthropoda? What specific thing are arthropods and what does this mean?
They are ecdysozoans, and ecdysis is a complex process that is regulated by hormones, but here is a simplified outline of the main features. Tissue growth, intermoult (instar), digestion of old endocuticle, secretion of new cuticle, old cuticle splits and sheds, moult, body swells (air/water), new cuticle hardens, new exoskeleton.
What is the phylum Arthropoda? What are they made up of?
7 articles, or podites
What is the phylum Arthropoda? What are the two processes called?
Uniramous, biramous
What is the phylum Arthropoda? What is uniramous?
Single process : endopod only, usually associated with walking
What is the phylum Arthropoda? What is biramous?
Two processes : endopod and exopod (can occur in crustaceans and trilobites) ; usually associated with swimming
What is the phylum Arthropoda? How does respiration occur?
Most arthropods have specialised systems, for gas exchange, which all function on the same two priniciples, which is to produce a high surface area to volume ratio, whilst also keeping the gas exchange organ moist. This is particularly challenging for the terrestrially adapted arthropods, such as insects, arachnids, and woodlice
What is the phylum Arthropoda? Excretion?
There are two methods of excreting waste and osmoregulation : nephridia and malphigian tubules. Nephridia take waste from the coelom and excrete it via special glands. Crustacea - antennal/maxillary glands, Arachnids - coaxal glands. Malphigian tubules, which are attached to the stomach and lie inside the body cavity. Arachnids, myriapods, insects, tardigrades.
What is the phylum Arthropoda? Vision?
Arthropods eyes are very different to the camera eyes of vertebrates and some molluscs. The simplest kind of eye is known as an ocelli, which is composed of a single lens and does not have a retina. More complex eyes are known as compound eyes, as they are composed of thousands of repeating ommatidia, each of which is a self-contained photoreception unit, consisting of a cornea, lens and photoreceptor cells.
What is the phylum Arthropoda? Summary?
Everything in the arthropods is defined by the exoskeleton. There are 4 subphyla within the arthropoda. Specialised physiological adaptations allow this phylum to colonise the aerial, aquatic, and terrestrial environment.
What is the phylum Arthropoda? What is the Subphylum Crustacea?
70,000 described species, maybe 500,000 undescribed. Crabs, lobsters, shrimps, prawns, barnacles, krill. Body usually of 3 tagmata - head (cephalon), thorax and abdomen - Cephalic shield or carapace usually present. 5 pairs of cephalic appendages 1. Mandibles, 2. 1st maxillae (maxillules), 3. & 4. 2 pairs of antennae, 5. 2nd maxilla. Usually compound eyes or simple ocelli, marine, freshwater and terrestrial, dominate marine environment. Size - from 100um to crabs with 4m legs
What is the phylum Arthropoda? What is the Subphylum Crustacea? What is the class Remipedia?
Only 12 species discovered since 1970s, found in tropical sea caves
What is the phylum Arthropoda? What is the Subphylum Crustacea? What is the class Cephalocarida?
Only 10 species, living in benthic marine sediments
What is the phylum Arthropoda? What is the Subphylum Crustacea? What is the class Branchiopoda?
1000 spp in 3 orders, Anostraca, Nostraca, Diplostraca. Mostly small freshwater shrimp - like animals ; often short lived. Produce drought resistant eggs
What is the phylum Arthropoda? What is the Subphylum Crustacea? What is the class Branchipoda? What is the order Anostraca?
Includes salt-tolerant brine shrimp. Live in ephermeal pools, hypersaline pools, ice lakes, desert pools - extreme environments. Feed on algae scraped from hard surfaces. Relatively large - 6-25mm long ; relatively slow - easy prey, live in habitats without predators.
What is the phylum Arthropoda? What is the Subphylum Crustacea? What is the class Branchiopoda? What is the order Notostraca?
12 spp, 2 - 10cm long. Called tadpole shrimps
What is the phylum Arthropoda? What is the Subphylum Crustacea? What is the class Branchiopoda? What is the order Diplostraca?
Described as bivalved branchiopods. Includes the suborder Cladocera. Water fleas such as Daphnia
What is the phylum Arthropoda? What is the Subphylum Crustacea? What is the class Malostraca?
> 40,000 spp ; the main and most well-known crustacean group. Characterised by a basic body plan consisting of 5-8-6 body segments, plus telson. i.e. head of 5 segments, thorax of 8 segments (peraeon to paraepods) ; abdomen of 6 segments (pleon to pleopods); telson or tail fan. Carapace covers all or part of thorax
What is the phylum Arthropoda? What is the Subphylum Crustacea? What are the three subclasses of the class Malostraca?
Phyllocarida (1 extant order = Leptostraca, 2 extinct orders). Hoplocarida (1 extant = Stomapoda, 2 extinct orders). Eumalostraca (3 extant superordera, composed of 1 extinct order, 14 extant orders).
What is the phylum Arthropoda? What is the Subphylum Crustacea? What is the class Malostraca? What is the subclass Phyllocarida?
Primitive malastracans with 5 - 8 - 7 body plan. All marine. 1 extant order - Order Leptostraca. Generally 5 - 15 mm long, some up to 5cm. Have large caraspace covering whole thorax, compressed laterally to form a unhinged bivalve shell.
What is the phylum Arthropoda? What is the Subphylum Crustacea? What is the class Malostraca? What is the subclass Hoplocarida?
350 spp ; stomatopoda or mantis shrimps ; prawn killers ; thumb splitters. 2-30cm in size, live in burrows in shallow tropical and subtopical marine environments. Carnivorous using large chelae of 2nd peraeopod to stab, crush or club prey.
What is the phylum Arthropoda? What is the Subphylum Crustacea? What is the class Malostraca? What is the subclass Eumalostraca?
3 superorders ; syncarida, eucarida, peracarida
What is the phylum Arthropoda? What is the Subphylum Crustacea? What is the class Malostraca? What is the subclass Eumalostraca? Super order syncarida?
1 extinct, 2 extant orders.
What is the phylum Arthropoda? What is the Subphylum Crustacea? What is the class Malostraca? What is the subclass Eumalostraca? Super order Eucarida?
3 extant orders, order Euphasiacea, order Decapoda.
What is the phylum Arthropoda? What is the Subphylum Crustacea? What is the class Malostraca? What is the subclass Eumalostraca? Super order Peracarida?
9 extant orders, order Mysida, order Cumacea, order Isopoda, order Amphipoda
What is the phylum Arthropoda? What is the Subphylum Crustacea? What is the class Malostraca? What is the subclass Eumalostraca? Super order Eucarida? Order Euphasiacea?
90 + spp - krill, euphasids. Have external gills, all pelagic marine, shrimp-like in appearance ; 4 - 15cm long. Suspension feeders ; often gregarious, forming huge swarms. Major food source for whales, squid, fish, birds. Many have photophores along body.
What is the phylum Arthropoda? What is the Subphylum Crustacea? What is the class Malostraca? What is the subclass Eumalostraca? Super order Eucarida? Order Decapoda?
18,000 + spp, shrimps, crabs, lobsters. Well developed carapace. 3 pairs of maxilipeds used in feeding, 5 pairs of peraeopods, 1st pair usually clawed (chelate), mostly aquatic, mainly benthic, 2 suborders : Natantia, swimming decapods - shrimps and prawns ; many are commercially important. Reptantia, heavy walkers - crabs, lobsters etc.
What is the phylum Arthropoda? What is the Subphylum Crustacea? What is the class Malostraca? What is the subclass Eumalostraca? Super order Eucarida? Order Decapoda? What is the suborder Reptantia?
4 infraorders : 1. Astacidae : marine lobsters & freshwater crayfish. Have strong tailfan ; first pair of peraepods heavily chelate ; well developed abdomen. 2. Palinura : crawfish and spiny lobster, all marine ; well developed abdomen. 3. Anomura : 5th legs reduced or turned inwards ; squat lobsters ; squat lobsters, porcelain crabs, king crabs and hermit crabs. 4. 4,500 spp, true crabs with broad carapace, 1st pair of legs heavily chelate (chelipeds) ; abdomen reduced and flexed beneath thorax
What is the phylum Arthropoda? What is the Subphylum Crustacea? What is the class Malostraca? What is the subclass Eumalostraca? Super order Eucarida? Order Decapoda? What is the parental care?
Most decapods have some parental care. Female carries the eggs on modified pleopods. Larval development then involved in several stages
What is the phylum Arthropoda? What is the Subphylum Crustacea? What is the class Malostraca? What is the subclass Eumalostraca? Super order Peracarida? Order Mysida?
1000 spp, Mysid and opossum shrimps, look similar to euphasids, but carry statocysts in uropods for orientation with gravity
What is the phylum Arthropoda? What is the Subphylum Crustacea? What is the class Malostraca? What is the subclass Eumalostraca? Super order Peracarida? Order Cumacea?
Small (few mm up to 2cm), have bulbois anterior and long slender posterior. Many remain buried in sediment, but change behaviour and swim during breeding
What is the phylum Arthropoda? What is the Subphylum Crustacea? What is the class Malostraca? What is the subclass Eumalostraca? Super order Peracarida? Order Isopoda?
Isopods, marine, freshwater and terrestrial. Tend to be dorsoventrally flattened. No carapace. 5cm to several cm’s long. Feed as scavengers, predators or parasites of fish and other crustaceans. About half known spp are terrestrial ; known as woodlice, pillibugs. Moch y coed (wood pigs)
What is the phylum Arthropoda? What is the Subphylum Crustacea? What is the class Malostraca? What is the subclass Eumalostraca? Super order Peracarida? Order Amphipoda?
8,000 spp, range from <1mm to 25cm. Carapace absent. Look similar to isopods but tend to be laterally flattened. Marine and freshwater, often intertidal, a few terrestrial spp. Some parasitic, most herbivorous, carnivorous or suspension feeders.
What is the phylum Arthropoda? What is the Subphylum Crustacea? What is the class Maxillopoda?
Several obscure groups, but only one important group - the barnacles. Subclass Theocostraca - Infraclass Asconthoracida : parasites of anthozoa and echinoderms. Infraclass Cirripedia : 1300 spp. Barnacles, the arthropod body plan unrecognisable in adults. Adult body plan modified for sessile life or parasitism. Larval stage pelagic. The cypris larvae has a bivalved carapace and is the settlement stage. Stands on its head, cementing it to the substrate, then develops a series of calcerous plates.
What is the phylum Arthropoda? What is the Subphylum Crustacea? What is the class Maxillopoda? What is the subclass Theocostraca?
Feeding is by suspension, filtering the water. Carried out by extending cirri (modified legs), as seen here in the sessile acorn barnacles on welsh shores, stalked barnacles have a peduncle to attach to their substrate.
What is the phylum Arthropoda? What is the Subphylum Crustacea? What is the class Maxillopoda? What is the subclass Tantulocarida?
Bizarre parasites of deep water crustaceans, consisting of little more than a sac like body of 0.5mm attached to host by a stylet.
What is the phylum Arthropoda? What is the Subphylum Crustacea? What is the class Maxillopoda? What is the subclass Branchiura?
130 spp, ectoparasites of fish (marine and freshwater), sucking blood and body fluids. Members of the genus Argulus are worldwide and often serious parasites of fish.
What is the phylum Arthropoda? What is the Subphylum Crustacea? What is the class Maxillopoda? What is the subclass Pentastomida?
130 spp, wormlike parasites of the respiratory tract of reptiles, mammals and birds.
What is the phylum Arthropoda? What is the Subphylum Crustacea? What is the class Maxillopoda? What is the subclass Mystacocarida?
13 spp, 0.5 - 1mm long, marine, interstitial crustaceans living in littoral or sublittoral sands, scraping organic material from surface of sand grains.
What is the phylum Arthropoda? What is the Subphylum Crustacea? What is the class Maxillopoda? What is the subclass Copepoda?
12,000 spp, 0.5 - 15mm, no carapace but possess a cephalic shield. Mostly free living and marine pelagic. Some benthic forms, some parasitic on invertebrates and vertebrates, particularly fish.
What is the phylum Arthropoda? What is the Subphylum Crustacea? What is the class Maxillopoda? What is the subclass Ostracoda?
13,000 spp, small bivalved crustaceans from 0.1 - 2mm. Most are benthic crawlers, but many planktonic, some parasitic on fish gills. Abundant worldwide, detritivores, scavengers, suspension feeders & some predators.
What is the phylum Arthropoda? What is the Subphylum Myriapoda?
11,500 spp. Terrestrial arthropods with just two tagmata, the cephalon and a long, many segmented trunk. Exoskeleton rarely has a wax layer ; gas exchange by trachea and spiracles. Two minor classes : Symphala (120 spp) 2-10mm long, living in soil and leaf mould, similar to centipedes, but have 12 pairs of legs & live on plant material. Pauropoda (500 spp) microscopic, soft, grub-like inhabiting leaf mould & soil, similar to millipides but only 9 pairs of legs. Feed on fungi and plant tissue. Two main classes : Chilopoda : centipedes, Diplopoda : millipedes.
What is the phylum Arthropoda? What is the Subphylum Myriapoda? What is the class Chilopoda?
Centipedes, 2,800 spp. Numerous unfused trunk segments, each with 1 pair of legs. Cane be up to 30cm long, mostly <10cm, usually reddish-brown. 1st pair modified as claws, contain venom. One pair of antennae. 15-193 leg-bearing segments ; worldwide distribution in soil, under stones, bark and logs. Carnivorous ; feed on arthropods but large ones may take frogs, mice and small snakes.
What is the phylum Arthropoda? What is the Subphylum Myriapoda? Locomotion in centipedes?
Laterally extended legs, keep body close to ground : increases stability, allows for long strides and speed. Legs either side of the body are out of phase ; as speed increases fewer legs are in contact with the ground. This allows greater speed but weak forward motion. Suits carnivorous lifestyle chasing live prey.
What is the phylum Arthropoda? What is the Subphylum Myriapoda? What is the class Diplopoda?
Millipedes, 8,000 spp. Trunk segments fused into pairs (diplosegments) so each bears 2 pairs of legs. Lack claws or venom glands, but many have repugnatorial glands on trunk segments that secrete noxious chemicals. Many species can roll into a tight ball when disturbed. Prefer damp shade, avoid light. Usually black or dark brown in colour. Length from 1 - 30 cm with well sclertoized and often calcified cuticle.
What is the phylum Arthropoda? What is the Subphylum Myriapoda? Locomotion in millipedes?
Short legs positioned ventrally, with body close to ground for stability. Left and right legs in phase and majority of legs in contact with ground at any one time - produces a slow but powerful gait. Suits lifestyle of slow-moving detritivores, bulldozing & burrowing through soil and rotten wood with a flat, broad head.
What is the phylum Arthropoda? What is the Subphylum Hexapoda?
1 million described species, with 3 - 100 million yet to be described. Arthropods adapted to terrestrial life, with modifications for aerial gas exchange. Body differentiated into head, thorax and abdomen. Each of the 3 thoracic segments (prothorax, mesothorax, metathorax) has a pair of legs. Wings often present on 2nd and 3rd sgements (forewings and hindwings) often joined by hooks. Have 1 pair antennae, mandibles and maxillae. 2nd pair of maxillae fused to form a labrum.
What is the phylum Arthropoda? What is the Subphylum Hexapoda? What are the two different class?
Entognatha and Insecta. Hexapod classification varies between authors. Basically classed into a class of primitive wingless - Class : Entognatha and the Class : Insecta. The insects are subdivided into the wingless Apterygota and the winged Pterygota further divided into - the ancient winged insects, with wings held horizontal. And the modern, wing-folding insects.
What is the phylum Arthropoda? What is the Subphylum Hexapoda? What is the class Insecta?
Insects inhabitat every possible terrestrial and freshwater habitat, although very few inhabit the marine environment. They are : Incredibly abundant, principal predators of other invertebrates. Play a key role in the diets of many animals. Play a major role as decomposers in terrestrial food webs, transmit a number of serious diseases to domesticated livestock and humans. Responsible for > 80% of the pollination of commercial crops.
What is the phylum Arthropoda? What is the Subphylum Hexapoda? What is the class Insecta? What is there basic arthropod exoskeleton?
It is strengthened in hexapods, protection from predators, increased support for terrestrial life, incorporates waxes to provide an effective barrier to water loss. The major advance for insects was the development of flight. The Apterygota arose prior to the evolution of wings, but all others are winged except for some groups such as fleas, lice etc that are secondary wingless. In some groups, the wings are reduced to a single pair, e.g. Beetle forewings modified to protective elytra. True flies have hind wings modified to form gyroscopic balance organs, halteres.
What is the phylum Arthropoda? What is the Subphylum Hexapoda? What is the class Insecta? Flight?
Power for flight usually comes from the elastic-mechanical properties of the exoskeleton, with changes in the shape of the thorax, rather than direct flight muscles, generating wing movement.
What is the phylum Arthropoda? What is the Subphylum Hexapoda? What is the class Insecta? Reproduction and development?
Hexapods are dioecious, most are oviparous, and many are parthenogenic. Most primitive insects are direct developers, producing juveniles that closely resemble adults. More advanced insects have complex indirect development, and undergo metamorphosis with different larval, pupal and adult forms. Some show incomplete metamorphosis, where young (nymphs) show stages (instars) that have similarities to adults.
What is the phylum Arthropoda? What is the Subphylum Hexapoda? What is the class Insecta? Reproduction and development? pt 2.
Some insects show complete metamorphosis, having a worm-like larva that is so different to adult form they are given different names, e.g. butterfly and moth larvae called caterpillars, fly larvae called maggots, beetle larvae called grubs. Such larvae are voracious feeders, with completely different mouthparts and diets to adults, and often attain a larger size than adults. Termination of larval life is accompanied by pupation. Pupae don’t feed or move much, and energy reserves are used for complete transformation of the body
What is the phylum Arthropoda? What is the Subphylum Cheliceriformes?
Primarily terrestrial, but some secondarily aquatic. Body divided into 2 tagmata, a prosoma (cephalothorax) & opisthosoma (abdomen). No antennae (the only arthropods to lack them). Prosoma has 6 pairs of appedanges. 1st pair are chelicerae, 2nd pair are pedipalps - both used for a variety of roles : sensation, feeding, defense, locomotion, copulation. 4 pairs of walking legs. Opisthosoma usually has a terminal telson. Only 2 classes : pycnogonida (a minor group of marine spiders), Chelicerata (all the rest).
What is the phylum Arthropoda? What is the Subphylum Cheliceriformes? What is the class Pycnogonida?
Sea spiders, >1,000 spp ; all marine, from intertidal to deep sea, mostly <1cm, but some deep sea spp can grown to >60cm. Anterior proboscis and ovigers, located between pedipalps and 1st legs, for brooding in males. Mainly free living and benthic, some show mutualism with anemones, hydroids and tunicates. Mostly carnivorous, sucking body fluids of small invertebrates. Some are algivorous
What is the phylum Arthropoda? What is the Subphylum Cheliceriformes? What is the class Chelicerata?
69,000 spp, includes horseshoe crabs, spiders, scorpions, mites, ticks, and various relatives.
What is the phylum Arthropoda? What is the Subphylum Cheliceriformes? What is the class Chelicerata? What is the subclass Merostomata?
Only 5 extant spp, many extinct spp. Horseshoe crabs live in shallow water of Nw atlantic, gulf of mexico and several asian coastlines. Grow to 60cm long, dark brown with a smooth carapace. Scavengers on molluscs, worms and algae ; congregate in intertidal for mating, burying small eggs in sand. Collected for their haemolymph, which is used in human pregnancy testing kits
What is the phylum Arthropoda? What is the Subphylum Cheliceriformes? What is the class Chelicerata? What is the subclass Arachnida? What is the order Acari?
Largest group of arachnids ; may be > million spp yet to discover. Mites are found in most environments. Free-living ones : from deep sea to intertidal, freshwater, in soil, on mosses & plants. Symbiotic mites live on freshwater, marine and terrestrial inverts and vertebrates. Parasitic mites : many are disease vectors, feed on stored produce, can be pests of crops. Often cause skin irritations and diseases in a range of mammals, including humans - scabies.
What is the phylum Arthropoda? What is the Subphylum Cheliceriformes? What are ticks?
Blood sucking ectoparasites on vertebrates ; chelicerae are modified for slicing skin. Hard ticks (family ixodidae) are heavily scleroticised and can remain attached to the host for days or weeks ; are vectors of various diseases including lyme disease and rocky mountain fever. Soft ticks (family argasidae) are transient parasites on birds, bats and other mammals
What is the phylum Arthropoda? What is the Subphylum Cheliceriformes? What is the class Chelicerata? What is the subclass Arachnida? and order Araneae?
The subclass Arachnida - mites, ticks, scorpions, spiders. The order Araneae - spiders. 35,000spp. The most familiar of all chelicerates, one of the most abundant groups of land animals. Prosoma undivided, covered by a shield & attached to fleshy opisthoma by narrow pedicel.
What is the phylum Arthropoda? What is the Subphylum Cheliceriformes? What are prosoma bears?
Chelicerae modified as fangs, usually with venom glands. Usually have eight eyes on dorsal surface, male pedipalps used for sperm transfer.
What is the phylum Arthropoda? What is the Subphylum Cheliceriformes? What are opisthoma bears?
Book lungs and/or trachea for respiration - pulmonate/apulmonate arachnids. Silk producing glands called spinnerets.
What is the phylum Arthropoda? What is the Subphylum Cheliceriformes? What is the order Scorpiones>
12,000 spp, the true scorpions. Body divided into : prosoma, with carapace like shield. Opisthoma is elongate & and divided into mesosoma & metasoma. Telson is spine-like, with venom gland. Pedipalps large and chelate. All terrestrial predators, external digestion of prey.
What is the phylum Arthropoda? What is the Subphylum Cheliceriformes? How do scorpions glow?
When exposed to certain wavelengths of UV. Presence of fluorescent chemical in the cuticle. A hand-held UV lamp has been a standard tool for nocturnal field studies of these animals. Fluorescence occurs as a result of sclerotisation, and increases in intensity with each successuve instar.
What is the phylum Arthropoda? What is the Subphylum Cheliceriformes? What are the remaining arachnid orders?
Whip scorpions, whip spiders, harvestmen, false scorpions, sun spiders. Spider silk - complex fibrous protein, produced in a liquid form which transforms into an insoluble thread as it leaves the body. Five times stronger than steel. Used for safety lines, climbing nets, nests, balloons, cocoons, traps and to catch prey. Mostly used in webs for prey capture - aerial filter feeders.
What is the phylum Tardigrada?
600 spp, water bears. Tardus = slow, gradus = step. Minute (0.3-0.5mm) aquatic, fresh, marine, also in water films around mosses and soil particles, in interstitial spaces between sand grains. Body covered by a thin chitnous cuticle that is moulted as the animal grows. Feed on algal or moss cells, or minute animals, by piercing them with stylets and sucking out the contents. Short, plump, cylindrical body. Four pairs of short stubby legs, each terminating in several claws.
What is the phylum Onycophora?
70 spp (onychos =claw, pherein = to bear). Ancient worm-like animals, live underneath stones, logs and leaves in humid tropics ; caterpillar like with numerous pairs of short legs. Body cylindrical from 1.5cm to 15 cm long. 2 antennae at anterior end ; body covered in tubercules.
