What is the significance of the hemocoel in arthropods?
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It is a reduced coelom that serves as a body cavity.
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What is the significance of the hemocoel in arthropods?
It is a reduced coelom that serves as a body cavity.
What are the three tagmata of Trilobita?
Head (cephalon), trunk, and pygidium.
How many described species are there in the Order Araneae (spiders)?
40,000 described species.
What percentage of all known species of animals does Phylum Arthropoda represent?
¾ of all known species of animals, more than 1.1 million species.
What is a major innovation in the morphology of Arthropoda?
Chitinous, segmented exoskeleton.
What are the two types of limb structures in Arthropods?
Uniramous (one part) and biramous (branched).
What are the two types of mouthparts found in Arthropods?
Mandibles and chelicerae.
What is the function of the versatile exoskeleton in Arthropods?
It provides protection while being flexible for mobility.
How does segmentation and appendages benefit Arthropods?
It is efficient for locomotion and allows for division of labor.
What system allows air to be piped directly into cells in Arthropods?
The tracheal air tube system.
What is a limitation on arthropod size related to respiration?
Air cannot get in deep enough to support larger sizes.
What role do good sense organs play in Arthropods?
They contribute to complex behavior patterns and understanding symbolism.
How does metamorphosis limit intraspecific competition in Arthropods?
Larval forms do not compete for resources with adults.
What is the example used to illustrate the concept of no parent-offspring competition?
DINK (double income no kids) concept.
What are the key characteristics of arthropods?
Jointed appendages, bilateral symmetry, segmented body, triploblastic with reduced coelom, cuticular exoskeleton, complete digestive system, complex muscular system, and a nervous system similar to annelids.
What type of exoskeleton do arthropods have?
Cuticular exoskeleton, sometimes with Calcium Carbonate.
How many segments can centipedes have?
A few to 177 segments.
What do millipedes primarily eat?
Most eat detritus, some living plants.
How do millipedes defend themselves?
They secrete toxic or repellent fluids from repugnatorial glands.
How many pairs of legs do millipedes have per segment?
Two pairs of legs per segment.
What is the reproductive behavior of female millipedes?
Females lay eggs in a nest and guard them.
What is the defining characteristic of Class Pauropoda?
Two pairs of legs per segment.
How many species are there in Class Pauropoda?
About 500 species.
Where do Pauropoda typically live?
In moist soil or leaf litter.
What are the physical characteristics of Pauropoda?
Soft bodied, small head with branched antennae, no true eyes, 12 trunk segments, one dorsal plate covering two segments.
What systems are absent in Pauropoda?
No tracheae, spiracles, or circulatory system.
What is the defining characteristic of Class Symphyla?
Small, centipede-like bodies.
Where do Symphyla typically live?
In leaf litter.
What is a common issue caused by Symphyla?
They are often pests on horticultural and agricultural crops.
How many segments do Symphyla have?
14 segments, 12 of which bear legs.
What type of antennae do Symphyla have?
Long and unbranched antennae.
What sensory features do Symphyla possess?
They are eyeless but have sensory pits at the base of their antennae.
What is unique about the reproductive process in one genus of Symphyla?
The male puts a spermatophore on the stalk, and the female stores it in her mouth, pulling eggs from her gonopore and attaching them to substrate with semen.
What type of development do Symphyla undergo?
Direct development.
When did Trilobita likely evolve and when did they become extinct?
They probably evolved before the Cambrian and became extinct 200 million years ago.
What type of environment did Trilobita inhabit?
They were dorsally flattened bottom dwellers, likely scavengers.
What is a notable feature of the Class Merostomata, Subclass Eurypterida?
They were giant water scorpions, some reaching up to 3 meters long, and were dominant predators of their time.
What adaptations did Eurypterida have for predation?
Their anterior appendages were modified into crushing claws to dent the dermal armor of early fishes.
What type of eyes did Eurypterida possess?
They had both simple and compound eyes.
What was the fate of the Eurypterida?
They are thankfully extinct, having existed from the Cambrian to the Permian.
What is the shape of the carapace of horseshoe crabs?
Unsegmented and horseshoe shaped.
How many extant species of horseshoe crabs are there?
Four species in three genera.
What is the long tail spike of horseshoe crabs called?
Telson.
What type of respiratory structures do horseshoe crabs have?
Book gills.
What do horseshoe crabs primarily feed on?
Worms and small molluscs.
When do horseshoe crabs come ashore to mate?
By the thousands at high tide during full moon and new moon.
How do horseshoe crab larvae resemble trilobites?
They hatch and resemble trilobites before being washed into the sea with the next high tide.
What is a unique feature of horseshoe crab blood?
It clots in the presence of bacteria.
What is the purpose of LAL derived from horseshoe crab blood?
It is used to detect gram-negative bacteria.
What is the survival rate of horseshoe crabs during blood extraction?
10-25% die during extraction, and those who survive often don't live long.
What challenges do female horseshoe crabs face in spawning?
They have trouble spawning, especially crossing the two-week period.
How many species of Pycnogonida are there?
About 100 species.
What is the size range of sea spiders?
Very small to 0.75 m across.
What are the distinctive physical features of sea spiders?
Small, thin bodies and four pairs of walking legs.
What unique feature do some male sea spiders have?
Some males have extra legs called ovigers.
What type of circulatory system do sea spiders have?
A simple circulatory system.
Which systems are absent in sea spiders?
Excretory and respiratory systems are absent.
How do the digestive system and gonads of sea spiders adapt to their body structure?
They branch into the legs due to limited space in the body.
What is the feeding behavior of sea spiders?
They are scavengers.
What are some examples of organisms in Class Arachnida?
Spiders, scorpions, pseudoscorpions, whip scorpions, ticks, mites, daddy longlegs, etc.
How many described species are there in Class Arachnida?
More than 80,000 described species.
What are the two main body segments (tagmata) of arachnids?
A cephalothorax and an abdomen.
What is the primary feeding behavior of most arachnids?
Most are predaceous.
What modifications do chelicerae have in arachnids?
They are sometimes modified into fangs.
How do arachnids help humans?
They are usually helpful as insect predators.
What is the significance of the hairs on arachnids?
They help arachnids feel vibrations, making them hard to squish.
What are the names of the cephalothorax and abdomen in spiders?
Cephalothorax is called prosoma, and abdomen is called opisthosoma.
What is the function of the chelicerae in spiders?
They have terminal fangs to transfer venom.
How many pairs of walking legs do spiders have?
Four pairs of walking legs.
What respiratory structures do spiders use?
They breathe through book lungs, trachea, or both.
What is the function of Malpighian tubules in spiders?
They work with unique resorptive cells in intestinal epithelium for excretion.
How many simple eyes do spiders usually have?
Usually eight simple eyes.
What is unique about spider silk?
For their diameter, spider silk is stronger than steel.
What are some uses of spider webs?
To capture prey, line nests or burrows, wrap prey items, and molting.
What precedes mating in spider reproduction?
A courtship ritual.
How does the male spider transfer sperm to the female?
By inserting pedipalps into the female's genital opening after depositing sperm in a small web.
What do female spiders do with their eggs?
They lay eggs in a silken net, may carry it or attach it to something.
What is the parental care behavior observed in spiders?
Females may carry their young.
What are the two dangerous groups of spiders in the U.S.?
Black widows and brown recluses.
What type of toxin do black widow spiders possess?
Neurotoxic.
What type of toxin do brown recluse spiders possess?
Hemotoxic.
How many species of scorpions are there?
About 1400 species.
What do scorpions primarily prey on?
Insects and spiders.
What is a unique feature of scorpions' eyes?
They have one pair of big median eyes and two to five pairs of small lateral eyes.
What is the structure at the end of a scorpion's tail?
A stinger.
What do scorpions use their comblike pectines for?
As tactile organs.
Describe the mating behavior of male scorpions.
They perform a complex mating dance, holding the female's chelae and caressing her mouthparts with pedipalps.
How do scorpions care for their young?
They brood and nourish them in the female's reproductive tract, and the babies crawl onto the mother's back until their first or second molt.
What is a characteristic of scorpions' claws?
Fat claws are not venomous.
What is the common name for the Order Solpugida?
Sun or camel spiders.
Are camel spiders venomous?
No, they are nonvenomous.
What is a notable feature of camel spiders?
They have large chelicerae that shred prey.
What is the maximum size of camel spiders?
Up to 15 cm across.
In what type of habitat are camel spiders usually found?
Desert habitats.
What is the metabolism rate of camel spiders?
They have a very high metabolism.
What is the myth associated with harvestmen (daddy longlegs)?
The idea that they are ultra venomous, but they cannot bite humans.
How many species of harvestmen are there?
Approximately 5000 species.
What is a distinctive physical feature of harvestmen?
Their abdomen and cephalothorax are rounded and broadly joined, with no pedicel.
What can happen to the legs of harvestmen?
They can be lost and regenerate.
What do harvestmen primarily feed on?
They are carnivorous and scavengers.
What is the dilution effect in relation to predators?
If there are many individuals, a predator may eat a neighbor instead of you, reducing individual risk.
How many described species are there in the Order Acari?
40,000 described species, with many more undescribed.
What are the largest ticks and mites in the Order Acari?
The largest are about an inch long.
What is a significant health issue caused by ticks and mites?
They cause the most health problems among arachnids.
What type of bacteria is associated with ticks and what is the recommended treatment?
Spirochete bacteria; antibiotics should be administered immediately.
What is a key anatomical feature of acarids?
Complete fusion of cephalothorax and abdomen, with no segmentation.
What are the mouthparts of acarids called?
Capitulum.
What do chelicerae do in acarids?
They are used for gripping and tearing food.
How many pairs of legs do most acarids have?
Usually four pairs of legs.
What is unique about the larval stage of acarids?
Larvae have six legs, while nymphs have eight legs.
What do chiggers feed on?
Dermal tissue.
What disease do deer ticks carry?
Lyme disease.
What is the primary cause of scabies?
Itch mites (Sarcoptes).
What is the main characteristic of the Subphylum Myriapoda?
They have two tagmata: head and trunk, with paired appendages on each trunk segment.
How do Myriapoda carry respiratory gases?
Through trachea.
What is the excretion method used by Myriapoda?
Through Malpighian tubules.
What is the defining feature of Class Chilopoda?
Centipedes have one pair of legs per segment.
What is the diet of centipedes?
They are extremely carnivorous.
