Week 10, Arthropoda Flashcards
Describe the general characteristics and biology of arthropods
→ They have an exoskeleton, which is usually hard
→ Their bodies are segmented
→ Their appendages are jointed (arthon = joint, pod = foot)
→ Through evolution their appendages became specialised
- locomotion (walking, jumping, flying, swimming)
- sensory perception - feeding - mating
What is “ecdysis”?
Moulting to shed an exoskeleton
What is hemolymph?
Analogous to blood in animals.
→ circulates throughout the body cavity
→ doesn’t transport gases
→ enters the heart through pores that are valves
→ heart pumps from tail → head
Describe the makeup and function of an arthropod’s exoskeleton.
→ Protect the arthropod’s body
→ Composed of layers of proteins and chitin (a polysaccharide)
→ Can be thick and hard, or thin and flexible at the joints
→ Impermeable to water and many chemicals
→ Needs to be moulted/shed (ecdysis) in order for the arthropod to grow
Describe some features of the Crustacea subphylum
→ 2-3 main body segments
→ antennae
→ ≥ 3 pairs of legs
→ mostly aquatic
→ e.g. prawns, crabs, pill bugs
Describe some features of the Myriapoda subphylum
Two main classes:
Chilopoda (centipedes)
→ One pair of legs per body segment
→ Odd number of pairs of legs
→ Predominantly carnivorous
→ Largest terrestrial invertebrate predators
Diplopoda (millipedes)
→ Two pairs of legs on most body segments
→ Mostly detritivores (dead plant material)
→ Distinct head with chewing mouthparts
→ Terrestrial
Describe some features of the Chelicerata subphylum.
→ Includes horseshoe crabs and arachnids
→ One or two main body segments
→ 6 pairs of appendages
- Chelicerae (pincer-/claw-like appendages near their mouths)
- Pedipalps (pincers on scorpions, sensory appendages on arachnids)
- 4 pairs of legs
→ Terrestrial and aquatic
Describe some features of the Hexapoda subphylum.
→ Includes insects, ∴ important for agriculture
→ 3 main body segments (head, thorax, abdomen)
→ Antannae
→ Three pairs of legs
→ Many have two pairs of wings
→ Mostly terrestrial
True or False?
Crustacea have 2 or 3 body segments
True.
True or False?
Crustacea have antennae
True.
How many pairs of legs do arthopods in the Crustacea subphylum have?
Equal to or greater than 3
Arthropods in the Myriapoda subphylum have sucking mouthparts
False; they have chewing mouthparts.
Give 2 examples of Myriapoda
→ Centipedes (Chilopoda)
→ Millipedes (Diplopoda)
What does the ‘Chilo’ and ‘Diplo’ prefixes represent for the two main classes of Myriapoda?
The number of pairs of legs per body segment.
- Chilopoda (centipedes) = 1 pair/segment
- Diplopoda (millipedes) = 2 pairs/segment
True or False?
Diplopoda are predominantly carnivorous
False.
Millipedes are mostly detritivores.
True or False?
Chilopoda are predominantly carnivorous
True.
Chilopoda = centipedes
True or False?
Centipedes have 2 pairs of legs/body segment (i.e. are members of the Diplopoda class)
False.
Centipedes (Chilopoda) only have one pair of legs/segment
True or False?
Millipedes have 2 pairs of legs/body segment (i.e. are members of the Diplopoda class)
True.