Transcript Invertebrates - Arthropods

Warm Up
What are the three groups of mollusks?
Invertebrates - Arthropods
“Jointed Legs”
Mollusks, Arthropods, and
Echinoderms
Arthropods
“Jointed Legs”
Chapter 10
Section 2
Discover Activity
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Will it bend or move? Page 335
Objectives:
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To identify four major groups of
arthropods and the main characteristics
of arthropods.
To describe how crustaceans,
arachnids, and centipedes and
millipedes differ.
Arthropods
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Arthropoda is the phylum of
invertebrates that contains the greatest
number of species.
Animals that make up this phylum
include
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crustaceans,
centipedes and millipedes,
arachnids and
insects.
Characteristics
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The three characteristics shared by all
arthropods:
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1. An exoskeleton.
2. A segmented body.
3. Jointed appendages.
Exoskeleton
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An exoskeleton is the most striking
characteristic of arthropods.
An exoskeleton is a rigid outer covering.
(Think of a suit of armor.)
One drawback of an exoskeleton is that it
doesn't grow as the animal grows. It must
be shed and replaced from time to time in a
process called molting.
Helps prevent water loss, so arthropods can
live in very dry climates.
Lobster Exoskeleton Dismantled
The exoskeleton of a lobster is
divided into a series of segments,
each of which performs specialized
functions. The cephalothorax,
consisting of the head and thorax,
bears all of the limbs used in sensory
perception, locomotion, breathing,
and the detection and capture of
prey. The abdomen is divided into six
segments that are responsible for
rapid locomotion.
Systems
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Open circulatory system
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Respiratory system, may have one or two of
the following systems
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Blood is not contained within small tubes
Pumped by a heart throughout spaces within the
arthropod’s body
Gills
Book lungs
System of air tubes
Reproduce sexually
Generalized Anatomy of a Crustacean
Crustacean anatomy is characterized
by an external skeleton and a
segmented body. In different
crustacean species these segments
and the accompanying limbs have
evolved into specialized appendages
for respiration, swimming, crawling,
and feeding. The extended inner
cavity contains the digestive and
nervous systems.
Crustaceans
Crustaceans
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Crustaceans include
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Crabs
Lobsters
Barnacles
Shrimp
Body
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Divided into segments
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Pair of appendages is attached to each
segment
Some crustaceans can regenerate
certain parts of their bodies
Live in watery environments
Have gills
Fairy Shrimp
Hermit Crab
Gooseneck Barnacles
Brine Shrimp
Spider Crab
Spot Prawn
Coconut Crab Climbing Tree
Pill bug
Centipedes and Millipedes
Centipedes and Millipedes
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Centipedes
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one pair of legs in each body segment
carnivores.
Millipedes
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two pairs of legs in each body segment
herbivores.
Peruvian Centipede
Centipede
Millipede
Arachnids
Arachnids
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Arachnids
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spiders
scorpions
ticks
mites
Arachnids
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An arachnid's body is divided into two
parts:
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1. A head and chest part.
2. An abdomen part.
All arachnids have four pairs (8) of
walking legs.
Spiders usually feed on insects (which is
good!)
Spiders
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Many spiders make webs.
All spiders produce silk, which is 5 times
stronger than steel.
Catch prey in a variety of ways.
Inject venom or poison using fangs, which
either kill their prey or paralyze it.
Have book lungs, which are several sheets of
tissues which resemble pages.
Generalized Anatomy of an Arachnid
African Wolf Spider
Web of the Funnel Spider
Wolf Spider
Scorpions
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Usually found in dry desert areas
Primarily active at night
Hide under logs, stones or in holes
during the day
Capture prey, hold it with their front
claws and inject it with venom through
the stingers in their tails
Scorpion
Sahara Fat-tailed Scorpion
Scorpion Tail
A scorpion’s tail usually curves upward and
forward over the back. A stinger at the tip
of the tail contains a pair of poison glands.
A scorpion paralyzes prey by a sting with
its tail.
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reserved.
Ticks and Mites
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Ticks and mites live on other organisms.
Many mites suck fluid from plants.
Some ticks and mites are very tiny
and live on insects.
Many ticks suck blood from larger animals.
They spread diseases like Rocky Mountain
spotted fever or Lyme disease.
Dust Mite
Chigger
Sheep Tick
Homework
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Guided Reading and Study Workbook
pages 141-144