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How can an insect nymph be distinguished from an adult? |
The phylum name means jointed foot. Jointed appendages is a major characteristic of all members of the phylum. The following are also traits
found in most arthropods:
All arthropods have an exoskeleton.
Once it is formed, this hard body covering does not grow. To allow for growth, arthropods have to shed their exoskeleton in a process called molting.
Most arthropods have compound eyes
composed of many individual lenses.
In addition to the compound eyes, many arthropods also have single lens, simple eyes that sense light intensity.
All arthropods have an open circulatory system.
This type of system has a heart and a few major arteries veins. There are very few capillaries connecting the arteries and veins. The blood spills into the body cavity where it is picked up and taken back to the heart. Arthropods are limited in size because of this inefficient circulatory system.
Subphyla of arthropods:
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 Horseshoe crab - which subphyla do they belong to? |
There are some 40,000 species in the subphylum Crustacea, ranging in size from copepods
and water fleas
that are just large enough to be seen with the unaided eye, to shrimp
that you might enjoy as food, to crabs,
some with a leg span of over 12 feet. The crayfish
is a freshwater crustacean in a group called decapods. Decapod means "ten feet", indicating that they have five pairs of legs.
Crayfish of the world:
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Appendages of the Crayfish
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Antennules Antennae Mandibles Maxillae Maxillipeds Chelipeds Walking Legs Swimmerets Uropods
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touch, taste, and equilibrium
touch and taste chewing manipulate food and draw water over the gills touch, taste, and manipulate food defense and capture food movement over solid surfaces create water currents and transfer sperm propulsion |
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Other Crayfish Structures
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Assignment 2.9a - Arthropods
- Right click on this
(Arthropods) and "save target as" to you desktop. After video has downloaded watch video and complete short quiz at the end. Write your answer here.
- Why is this phylum named the arthropods?
- What are the phylum characteristics?
- Does the arthropod circulatory system differ from that of the Annelida? Explain.
- Which arthropod subphylum are crayfish classified under?
- What is the scientific name for a crayfish that is found in Arizona?
- List the common and scientific name of one member each from the Uniramia and Chelicerata subphyla.
- Cut and past into word (or draw) a external and internal diagram of a crayfish. Label as many parts as possible (Do not cut and paste a crayfish that is already labeled). Crayfish must be labeled by you.
Honors biology: complete the above section along with the following section.
- Research one specific arthropod (not a crayfish) and list the common and scientific name. Summarize all important characteristic about your arthropod (habitat, reproduction, niche, feeding, movement, body parts, region found, interesting facts, etc).
Section 9 part b Arthropoda
Other arthropods:
Characteristics:
Class Arachnida: subphylum Chelicerata
The largest class in the subphylum Chelicerata contains more than 70,000 species including ticks, mites, spiders, and scorpions. Arachnids have a body divided into a cephalothorax and abdomen. The cephalothorax usually bears six pairs of jointed appendages: one pair of chelicerae (fangs), one pair of pedipalps (hold and chew food), and four pairs of walking legs.
Scorpions
are a familiar site in Arizona. The bark scorpion has a very toxic venom.
Ticks
carry some serious
diseases and should be regarded with caution.
In Northern Arizona, mites called chiggers
can cause a lot of discomfort.
All spiders are poisonous.
Most spiders are not aggressive and their bite is no worse than a bee sting.
spiders in and around the house
tarantulas
(no tarantulas in the U.S. are harmful to humans)
Only two spiders in the U.S. have bites that are normally harmful to humans.
black widow spider
brown recluse spider
Class Diplopoda:
millipedes, subphylum Uniramia.
Two pairs of weak legs per body segment.
Slow-moving with a rounded body.
These plant-eating animals do not have a sting.
When threatened, they coil up and secrete a noxious fluid
containing cyanide.
Class Chilopoda:
centipedes, subphylum Uniramia.
One pair of strong legs per body segment.
Fast-moving with a flattened body.
These carnivorous animals have a pair of poison jaws, not a stinger.
Class Insecta:
insects, subphylum Uniramia.
The body of an insect is divided into three parts:
Head - with one pair of un-branched antennae and the mouth parts.
Thorax - with three pairs of jointed legs
(6 total) and, in many species, one or two pairs of wings.
Abdomen - has neither legs nor wings.
Exoskeleton - hard body coveringGo through metamorphosis
Keys to the Orders of insects.
Forensic Entomologist |
Local links to insect drawings:
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All insects go through one of two types of metamorphosis:
Insect defensive adaptations:
The grasshopper is generally used as a "typical" insect for anatomy study.
2.9b part 1 Paste this grasshopper diagram
2.9b Part 2 Honors biology: Include these questions with the day
2.9b part 2 assignment
An insect nymph looks like the adult, except it does not have wings or sexual structures.
which enhances their chance of survival. Since the larval and adult stages usually live in different habitats and eat different foods, they do not compete for space and food. Most butterflies and moths spend the winter in the pupa stage, often buried in the ground.
The stages of complete metamorphosis:
The pupa of moths is enclosed in a protective case called a cocoon.
The stages of incomplete (simple) metamorphosis:
Insects have a wide range of defensive adaptations that increase their chances for survival. These range from passive, like camouflage, to aggressive, such as the venomous stingers of bees and wasps. Insects that defend themselves by being dangerous or poisonous often have bold, bright color patterns that make them clearly recognizable and warn predators away. This type of coloration is known as warning coloration. Several dangerous species have similar patterns of warning coloration, such as the black and white stripe pattern found on many wasps and bees. This adaptation, in which a member of one dangerous species mimics the warning coloration of another, is called Mullerian mimicry.
Some harmless species also mimic the warning coloration of a dangerous species. This type of mimicry is known as Batesian mimicry.
Head lice
are also insects.
Test your knowledgeof insects and spiders.
Assignment 2.9b - Arthropods
onto a Word document, enlarge and label the following parts. Below the diagram give a brief definition of each part.
onto a Word document, enlarge and label the following parts. Below the diagram give a brief definition of each part.
. Read the information and test your comprehension by taking the quiz linked
at the bottom. How did you do? Cut and past your results here.
(B)
(C)
of the most venomous, the most common and least common scorpions found in Arizona. Using the pictures find
the common and scientific names of each (finding a identification key will be helpful).
to find and list all the characteristics use to identify this type of scorpion.
Research Links:
