Phylum: Arthropoda
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Phylum: Arthropoda
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Arthropoda
Origin of the word Arthropoda: Jointed Foot
Common Examples: Insects, Spiders, Crabs
Symmetry: Bilateral
Type of body cavity: Coelomate
General Arthropod Body Plan
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Characteristics of Arthropods
1) Jointed appendages: Arms and legs with freely
moving joints.
Early arthropods:
have appendages
on each segment
Modern arthropods:
have appendages
on a few
segments.
Specialization of Appendages
Functions of Appendages:
1) Running
2) Catching prey
3) Feeding (Sharp mandibles)
4) Swimming
5) Reproducing
6) Sensory reception
Exoskeleton
2) Exoskeleton: Strong chitin shell found on the
outside of the organisms body
Used for:
- Protection
- Skeleton to support muscle
- Prevent desiccation (drying out)
Exoskeleton
Molt: The exoskeleton is
not capable of
expanding. When the
organism inside the
exoskeleton grows too
large it must form a
new exoskeleton inside
the old one. When the
new one is ready it will
shed the old one. Once
free the new
exoskeleton expands
and hardens
Segmentation
3) Segmentation in arthropods: Segments are
fuse into regions.
Nervous System
Arthropod Nervous System: Three parts
1) Brain
2) Ventral solid nerve
cord
3) Sense organs:
- Antennae
- Simple eyes
- One pair of
compound eyes
Compound eyes produce a clearer image then the
mammalian eye
Subphylum: Crustaceans
Crustaceans: Have high levels of calcium in their
shells
- Mainly marine arthropods. Barnacles, crabs,
lobsters and shrimp
- Freshwater examples include crayfish,
freshwater crabs and shrimp.
- Land examples include pillbugs
Subphylum Uniramia
Subphylum Unirami: Insects
Entomology: The study of insects
Characteristics of insects:
1) Three parts of the body: head, thorax, abdomen,
2) One pair of eyes and several smaller eyes
Subphylum Uniramia
Subphylum Unirami: Insects
Entomology: The study of insects
Characteristics of insects:
1) Three parts of the body: head, thorax, abdomen,
2) One pair of eyes and several smaller eyes
3) One pair of antennae
4) Specialized mouthparts
Subphylum Uniramia
Subphylum Unirami: Insects
Entomology: The study of insects
Characteristics of insects:
1) Three parts of the body: head, thorax, abdomen,
2) One pair of eyes and several smaller eyes
3) One pair of antennae
4) Specialized mouthparts
5) One or two pairs of wings
- Escape enemies
- Finding food
- Mating
- Dispersing offspring
Subphylum: Chelicerates
Subphylum: Chelicerates (Arachnids Scorpions,
Spiders, ticks, mites)
1) 6 pairs of appendages
- 2 chelicerae
- 2 pedipalps
- 4 pairs of walking legs
2) Two body parts:
- Cephalothorax: Head and legs
- Abdomen: Contains the organs
Assignment
• Vocab: 640 - 646