Phylum Arthropoda. Arthropods Make up about 80% of the known animal species Insects are by far the...
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Transcript of Phylum Arthropoda. Arthropods Make up about 80% of the known animal species Insects are by far the...
Phylum Arthropoda
Arthropods
Make up about 80% of the known animal species Insects are by far the most common species of arthropods
Arthropod means joint-footed Range from the deep sea to mountain peaks
Bilateral symmetry Growth requires molting
General Arthropod CharacteristicsArthropods have:
1. Exoskeleton - Most prominent characteristic is their outside skeleton, or exoskeleton.
- Exoskeleton provides support, protection and attachment site for muscles. Made of protein and chitin Chitin is a strong, flexible, polysaccharide
- All arthropods molt, or shed their exoskeletons periodically. After it molts, it grows before the new skeleton hardens.
- Skin glands digest the inner part of the exoskeleton and other glands secrete the new one.
http://www.youtube.com/watch?v=ffo37DlH5DM
General Arthropod Characteristics
Arthropods have:
2. Segmented Bodies - Have segmented bodies that show various patterns of segment fusion (tagmosis) to form integrated unit like the head, abdomen, ...
General Arthropod CharacteristicsArthropods have:
3. Jointed Appendages
- Have joints between body sections (includes legs and antennae)
- Have jointed appendages (a structure such as a leg that grows out from the main part of the body)
Arthropod Characteristics
Cephalization is more prominent than in annelids (brain and complex sense organs in the head region)
Special organs sense touch, vibration, and chemicals. The eyes of many arthropods are particularly specialized.
Open circulatory system. The dorsal heart pumps blood from the posterior end of the animal to the anterior end. - Blood moves through the hemocoel (major body cavity)
Phylum Arthropoda – 2 Subphylum
Subphylum Chelicerates Class Arachnida
Spiders, scorpions, mites, ticks Subphylum Mandibulates (4 major classes) Class Crustacea
Crayfish, Crab, Lobster Class Chilopoda
Centipedes Class Diplopoda
Millipedes Class Insecta
Insects, Grasshoppers
Subphyla Chelicera
Chelicera are pointed appendages (modest pinchers) used for feeding and manipulating food (in lieu of chewing mandibles)
The body of chelicerates has two major parts: 1. The cephalothorax is a fused section composed of the head and any body segments that have legs attached.
2. The abdomen consists of posterior segments that contain most of the internal organs.
Lack antennae Nearly all have 4 legs
http://www.youtube.com/watch?v=Cha-lmuPdek
Subphlya Chelicera:Class Arachnida
Subphyla Mandibulata
Unlike chelicerates, mandibulates have - mandibles, or jaws, for chewing food.
All mandibulates have antennae - segmented sense organs on the head
Three distinct body regions - head, thorax, abdomen
They have three or more pairs of walking legs
Subphyla Mandibulata: 1. Class Crustacea
Crustaceans typically have: - two pairs of antennae - two or three body sections
Cephalothorax – head fused with the thorax
- chewing mouthparts called mandibles.-5 or more pairs of legs
• Primarily aquatic, few terrestrial
Ex: Crustacean
Subphyla Mandibulata:2. Class Chilopoda (centipedes) & 3. Class Diplopoda (millipedes)
Subphyla Mandibulata: Class Insecta
Insects typically have: The three distinct segments (head, thorax, abdomen)
Three pairs of legs attached to the thorax
Mandibles One pair of antennae One pair of compound eyes Two pairs of wings on the thorax Tracheal tubes for respiration
Tracheal tubes open to the outside through small holes called spiracles