Phylum Arthropoda
What are arthropods?
 Insects
 Crabs
 Centipedes
 Millipedes
 Spiders
Why are they grouped even
though they are so different?
 All have segmented bodies
 Tough exoskeleton
 Jointed appendages
Question
 What does “exo” mean?
Exoskeleton
 Tough outside covering
 armor
 Made from protein and a carbohydrate
 CHITIN
Question
 How do arthropods grow if they have tough
exoskeletons, that don’t grow?
Answer
 Arthropods molt – means they shed their exoskeleton
and grow a new one
 http://www.youtube.com/watch?v=DdpNBOiRbgg
Variations in Exoskeletons
Question
 What is an appendage?
Appendages
 Arthropods have jointed appendages
 This is why they got their name – means “joint foot”
Groups of Arthropods
 Crustaceans
 Arachnids
 Insects
Insects
 Body divided into 3 segments
 Head
 Thorax
 Abdomen
 3 pairs of legs attached to the thorax
Class Insecta
Question
 How many body segments do insects have?
 Which segments are the legs attached to?
Compound Eyes
 Eye is different from vertebrates because it is made up
of hundreds of different lenses.
What is metamorphosis?
Metamorphosis refers to
the way that certain
organisms develop, grow,
and change form.
Metamorphosis actually
means "change".
Two Types of
Metamorphosis
 INCOMPLETE METAMORPHOSIS - has THREE stages
 COMPLETE METAMORPHOSIS has FOUR stages.
3 STAGES OF
INCOMPLETE
METAMORPHOSIS
Egg
Nymph
Adult
COMPLETE METAMORPHOSIS
Let’s take a closer
look
at each stage!
4 STAGES OF
COMPLETE METAMORPHOSIS
Egg
Larva
Pupa
Adult
QUESTION #1
 What are the two
types of
metamorphosis?
1. Complete
2. Incomplete
QUESTION #2
 How many stages are
there in incomplete
metamorphosis?
Answer: 3
QUESTION #3
 Name the stages of
incomplete metamorphosis?
1. Egg
2. Nymph
3. Adult
QUESTION #4
 How many stages are
there in complete
metamorphosis?
Answer: 4
QUESTION
#5
- Name the stages in
complete metamorphosis.
1.
2.
3.
4.
Egg
Larva
Pupa
Adult
QUESTION #6
Identify the cycle as complete or
incomplete metamorphosis.
QUESTION #7
Identify the cycle as complete or
incomplete metamorphosis.
QUESTION #8
D
E
C
F
B
A
Identify each stage of the complete
metamorphosis of the butterfly.
Insect Orders
 Coleoptera – Beetles
 https://www.youtube.co
m/watch?v=mXIuSXFGXk
Insect Orders
 Orthoptera –
Grasshoppers/Crickets
 http://www.youtube.com
/watch?v=prafMmD_mx8
 Temp (F) = # of chirps in
14 seconds + 40
Crustaceans (sub phylum)
 Primarily aquatic
 Typically have 2 pairs of branched antennae
 2 or 3 body sections
 Mandibles (chewing mouthparts)
Crustacean Pictures
Typical Crustacean
Cephalothorax
 Formed by fusion of the head and thorax (right after
head)
 Most of the internal organs are inside
Abdomen
 Posterior part of the body
Carapace
 Part of exoskeleton that covers the cephalothorax
Appendages
 Projecting part of an organism – can you give me
examples?
Appendages in Crustaceans
 Crayfishes, Lobsters, & Crabs are members of the
largest group of crustaceans – the decapods
Question
 What does “deca” mean?
Order Decapoda
 Have 5 pairs of legs = 10 legs total
 1st pair called chelipeds have large claws
 Other 4 pairs – walking legs
 Swimmerets – along abdomen flipperlike appendages
used for ….
Questions
 What are the body segments of a crustacean?
 What are the first 2 pairs of appendages used for?
 What are swimmerets used for?
 What does decapod mean?
Chelicerates (sub phylum)
 Horseshoe crabs
 Spiders
 Ticks
 Scorpions
Arachnid Body Plan
 Mouthparts called chelicerae
 2 body sections
 Cephalothorax & Abdomen
 Nearly all have 4 pairs of walking legs
 http://www.bing.com/videos/search?q=what+to+do+if+gol
iath+spider+lands+on+you&FORM=VIRE1#view=detail&mi
d=BC79A223F203EBC61BDABC79A223F203EBC61BDA
 Have 2 pairs of appendages attached near the mouth
(adapted as mouthparts)
 1 pair chelicerae (fangs)
 Other pair pedipalps (grab prey)
Class Arachnida
 Do not have jaws – must liquefy food to eat it
 Uses fanglike chelicerae to inject paralyzing venom, then
digestive enzymes – allows them to suck it into a
specialized pumping stomach
 Most have “book lungs” – not like our lungs named
because of shape – place for gas exchange to happen
 Spiracles are openings that allow air in for gas
exchange
Spider
 https://www.youtube.com/watch?v=d_yYC5r8xMI
Question
 What are spinnerets used for in spiders?
Spinnerets
 Organs that contain silk glands – whether or not the
spider spins webs they make silk
Questions
 What are the two groups of chelicerates?
 What is a cephalothorax?
 How many body segments do chelicerates have?
More Arachnids
 Mites & Ticks
 Scorpions
Mites & Ticks
 Usually parasitic
 Their chelicerae and pedipalps are used for diggings and
sucking
 Chelicerae usually needlelike to pierce skin
 Pedipalps often equipped with claws for attaching to host
Scorpions
 Pedipalps enlarged into
claws
 Abdomen – has the
venomous stinger
 Actually chew their prey
using their chelicerae
 https://www.youtube.co
m/watch?v=7e4tyhLbGB
Q
Uniramians
 Includes insects, centipedes, and millipedes
Uniramians (group)
 Have jaws
 One pair of antennae
 Unbranched appendages
Class Diplopoda
 What does “di” mean?
Class Diplopoda (Millipedes)
 Highly segmented body
 Each segment has 2 pairs of legs (comes from segment
fusion in the embryo)
 Eat decaying matter
 Defense
 Curl up into a ball
 Secrete unpleasant/toxic chemicals
Class Chilopoda (Centipedes)
 1 pair of legs per segment
 Carnivorous – mouth has venomous claws
 Their spiracles cannot close – what are spiracles?
 They lose water easily – restricted to most or humid areas