Flashcards in Lecture 5 DA Deck (81)
Which phylum is the most diverse (percentage)?
Arthropoda, at over 75%.
What are the key features of arthropoda (10)?
-Coelomates, with a reduced coelom
What is heteronomous and homonomous segmentation?
Hetero - segments differ
Homo - segments are the same
What is tagmatisation?
Multiple segments fuse into distinct regions.
What is a cuticle, what two forms does it have, and for what kind of environment?
Made of chitin, and can be reinforced with calcium for aquatic environments, and waxy for terrestrial.
What are the functions of the cuticle (3)?
Prevents water loss
What is a disadvantage of having an exoskeleton/cuticle?
Must molt periodically.
What is ecdysis, and how does it occur?
Molting process. The arthropod first engores on water to expand, cracking the exoskeleton.
Will then crawl out, and continue to engorge to stretch its underskeleton, which will later harden. It will then shrink.
How does molting put the arthropod at a disadvantage?
Is vulnerable during this stage, from predators, competition from its own species, or exhaustion from crawling out.
Predation is the biggest threat.
How is the arthropod tracheal system structured?
Cuticle extends into the body to deliver oxygen to the tissue. The hollow tubes are an invagination of the cuticle.
What are the external openings in the tracheal system of arthropods called?
Do spiracles have valves?
Some do, aids in water loss.
What are wings believed to be formed from?
Evagination of the cuticle.
What are ommatidia?
Compound eyes, which arthropods have.
What are antennae and anntenules used for?
Mechano- and chemoreceptors.
What are the subphyla of arthropoda (5)?
What are the general characteristics of trilobites?
Biramous appendages, and one pair of anntenae.
What are the general characteristics of crustaceans?
Biramous appendages, two pair of anntenae, and a nauplius larva.
What are the general characteristics of chelicerates?
Uniramous appendages, no antennae.
What are the general characteristics of myriapods?
Uniramous appendages, and one pair of antennae.
What are the general characteristics of hexapods?
Uniramous appendages, one pair of antennae, and no abdomen appendages.
What environment do crustaceans live in?
Mostly aquatic, some terrestrial.
Are barnacles crustaceans?
How many tagmata do crustaceans have, and what are they?
3, a head, thorax and abdomen.
In some, the head and thorax is fused.
What is a tagmata that is a fused head and thorax called?
Cephalothorax or carapace.
How many pairs of appendages do crustaceans have on their head?
The first pair are antennules, and are small.
Second pair are antennae, much larger.
Next pair are mandibles.
Next two pairs are maxillae for manipulating food.
Are crustacean thorax segments number constant? Can these segments be used to manipulate food?
Segment number is variable, the most common is 8. First 3 can be turned forward, specialised to manipulate food.
The first 3 segments of a crstacean's thorax is used for food. What about the other 5?
They are called pereopods, used for locomotion.
What segments are large claws formed from in some species?
First pair of the pereopods on the thorax.
How many appendages do crustaceans have on their abdomen?
6, called pleopods.
What is a telson?
A tail, found on the abdomen.
What is meant by a biramous appendage?
Each appendage has two lobes.
The lobe closer to the midline is called endopod, while the outer one is the exopod.
What are gills of crustaceans associated with(which segment)?
Where are crustacean gills found?
Is found in a cavity in the carapace that water flows through.
What can crustaceans do that allows them to escape predators?
Can automize their appendages, break it off to avoid the threat. Special muscles used to crack the joint.
Regenerates after molting.
What can be found in the stomach of crustaceans to aid in digestion?
Bits of exoskeleton for grinding.
Which end is the anus found in crustaceans?
Do crustaceans have an open or closed circulatory system? What is it like?
Open, with a heart ostia and blood sinuses.
Where are crustacean metanephridia found, and what is it called?
One set found in the head, called antenneal gland.
What are the brains of crustaceans like?
They have segmented ganglia.
If a crustaceans automize their leg, are the gills affected?
No, despite the association.
Do maxillae or maxillpeds aid in water breathing, or purely food manipulation?
Aid breathing by drawing water across gills.
Are crustaceans mon or dioecious?
Most are dioecious.
What happens to crustacean eggs after they are fertilised?
Brooded by females.
What do crustacean eggs hatch into? What about terrestrial ones?
All produce nauplius larva, which are free swimming.
Terrestrial ones go through this stage in their egg.
What two structures do nauplius larva have?
Nauplial eye in the middle.
A claw called cheliped.
Are barnacles mono- or dioecious? How do they reproduce?
Are hermaphrodites, with extendible penises to reach other barnacles.
What distinguishes the crustaceans?
How do crustaceans swim/walk?
They use pleopods or pereopods in waves of power and recovery strokes, looks like its undulating, but isnt.
Can crustaceans burrow?
Yes, they use their appendages.
How do crustaceans feed (3)?
Use maxillipeds to draw water across its antennae, as well as pereopods.
Uses chelipeds or 2nd antennae
Chelipeds, or stabbing pereopods.
What subphyla are insects?
How many antennae and tagmata do hexapoda have?
One pair of antennae, and 3 tagmata, prothorax, metathorax and mesothorax.
What kind of cuticle do hexapoda have vs crustaceans?
Waxy, vs calcareous in crustaceans.
How many pairs of legs do hexapods have and on which tagmata?
3 pairs on the metathorax.
What are malpighian tubules and what do they do?
Tubules called tracheae, found along the digestive tract, and secrete into it. Additional water can be reabsorbed here, allowing it to produce concentrated waste.
Do hexapod spiracles have valves?
Usually they do, aid in water loss.
What structure do mandibles have in hexapods?
What are maxillae of hexapods used for?
Can be modified for different uses such as manipulating food, sucking blood/nectar, herbivory, scavenging or predation etc.
How many pairs of wings do most winged hexapods have?
Most have 2 pairs, some have one pair reduced, or specialised to form something else.
ie a cover in beetles.
What is the purpose of veins on the wings of hexapods?
Allow it to alter the shape of the wing.
How do wings flap in hexapoda?
Thorax compression, causing oscillation about the joint, very efficient for flapping.
Is the wing joint a true joint?
Not a true joint, more like a pivot.
What is an instar?
Stages in between a series of molts.
What are the two patterns to the development of instars?
Insect changes gradually, its first instar form similar to its adult stage, with no dramatic change, with maybe some small changes.
What is the advantage of holometabolous instars?
Allows it to divide its lifecycle for different functions. ie Adult stage used for dispersing, larval stage for growth.
How many tagmata do myriapoda have?
2, head and trunk.
What kind of cuticle do myriapoda have?
Are myriapoda spiracles closable? What is a consequence of this?
No, they cant be closed. Need to live in damp areas as a result.
Do myriapoda use malpighian tubules?
What are the two orders of myriapoda?
Chilopoda - centipedes.
Diplopoda - millipedes.
How many leg segments do chilopoda have per segment?
1 leg per segment except their last segment.
What is the function of the last pair of legs in chilopoda?
Are defensive or sensory.
What is a feature of myriapoda?
They have repugnant glands.
What is the function of the 1st maxilliped pair in chilopoda?
Has forcipules, can inject toxins.
How are diplopoda segmented?
Are diplosegmental, in repeating segments of fused segment pairs.
What are the legs of diplopoda like per segment?
1st segment has no legs, 2nd-4th have only one pair of legs, all others have two pairs per segment.
Do diplopoda have repugnant glands like chilopoda?
Which are faster, chilopoda or diplopoda?
Which has a harder cuticle, chilopoda, or diplopoda?