Transcript Arthropods - BIO PROF. MICHELLE WALTERS

Arthropods are one of the most diverse and
successful animals of all time, it is the largest
phylum of animals.
 The phylum is named for: arthron
means “joint” in Greek, and podos
means ‘‘foot”.
 This phylum includes animals such as
insects, crabs, centipedes, crustaceans
and spiders.
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Arthropods have a segmented body, a tough
exoskeleton, and joined appendages.
They use complex organ systems,like a welldeveloped heart with an open circulatory
system, nervous system, and groups of
muscles.
Terrestrial arthropods breathe through tracheal
tubes and book lungs, while aquatic breathe
through featherlike gills.
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In excretion, most terrestrial arthropods
dispose of nitrogenous wastes using
Malpighian tubes, while aquatic have
diffusion.
Terrestrial have internal fertilization, while
aquatic have both internal or external.
When they outgrow their exoskeleton,
arthropods undergo periods of molting.
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Arthropods include herbivores, carnivores,
and omnivores.
There are arthropods bloodsuckers, filter
feeders, detritivores, and parasites.
Arthropod mouthparts have evolved in
ways that enable different especies to eat
almost any food you can imagen.
Their mouth parts range from pincers or
fangs to sickle-shaped jaws that can cut
through the tissues of captured prey.
Arthropods are classified based on the number and structure of
their body segments and appendages particularly their mouthparts.
 The three mayor groups are crustaceans, spiders and their relatives,
and insects and their relatives.
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Animals in subphylum Crustacea
are primarily aquatic.
Crustaceans typically have two pairs of
antennae, two or three body sections, and
chewing mouthparts called mandibles.
This subphylum includes organisms such
as crabs, shrimps, lobsters,
crayfishes, and barnacles.
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Fast Facts
Type: freshwater
crustacean
Diet: (They help clean the
water by scavenging on
dead matter)
Size: 2 to 6 inches (5 to 15
centimeters) long
Crayfish live under rocks and debris on the muddy bottom of
freshwater lakes, streams and rivers. They are active at night
and crawl along the mud feeding on aquatic vegetation, worms,
insects, mollusks, and decayed organic matter.
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They scavenge on fallen leaves, seedlings, fruits,
and flowers, recycling nutrients and helping to
determine the spread and composition of native
flora.
Fast Facts
Type: Invertebrate
Diet: Omnivore
Size: 5 in (12.7 cm)
Group name: Streams
Protection status: None
Did you know? Red
crabs can stop traffic,
puncture tires, and
wander through any
open doors during their
migration to the sea.
Size relative to a tea
cup:
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Horseshoe crabs, spiders, ticks, and
scorpions are members of subphylum
Chelicerata.
Chelicerates have mouthparts called
chelicerae and two body sections, and
nearly all have four pairs of walking legs.
Lack of antennae.
The bodies of chelicerates are divided into a
cephalothorax and an abdomen.
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Fast Facts
Type: Bug
Diet: Carnivore
Average life span in the
wild: Up to 30 years
Size: 4.75 in (12 cm) long;
leg span, up to 11 in (28 cm)
Weight: 1 to 3 oz (28 to 85
g) Size relative to a tea cup:
“Horseshoe crabs have gone basically unchanged for 360
million years. But can they survive human predation? ”
- Jordan Schaul
Horseshoe crabs are considered living
fossils. The elegant, but simplistic design
includes a basic, hard, curved exoskeleton
(carapace) protecting an underbelly of soft
tissue–characteristics that have permitted
them to evade predation by a variety of
species that have long gone extinct. Live
primarily in and around shallow ocean
waters on soft sandy or muddy bottoms.
They are able to survive a year without
food, and endure extreme temperatures,
and dramatic changes in salinity levels.
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Fast Facts
Type: Bug Diet: Carnivore
Average life span in the wild:
3 to 8 years
Size: Average, 2.5 in (6 cm);
Largest, 8.3 in (21 cm)
Did you know? Scientists
aren't sure why, but scorpions
are fluorescent under
ultraviolet light.
Size relative to a tea cup:
Ecological importance
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Arthropods are of ecological importance because of their
sheer numbers and extreme diversity. More than 874,000
living species of arthropods have been identified, making
up more than 80 percent of all named species of animals.
However, it is estimated that many more thousands of
arthropods exist that have not yet been named.
Most of these unnamed species are small beetles and
other insects, and most of these occur in old-growth
tropical rain forests—areas that have not yet been
well explored.
Arthropods are both harmful and helpful to humans.
A few species are transmitters of bacteria or viruses
that cause diseases such as malaria, etc. Some
arthropods are a nutritious source of food in many
parts of the world, and insects play an important role
in pollination (a process necessary for production in
many plants).
Eventually they
reach a leg-span of
over 3 feet and a
weight of 10
pounds. Coconut
crabs live on island
beaches throughout
the Indian and
South Pacific
Oceans. They live in
dirt burrows and
rock crevices, and
scavenge for fruits
and nuts, including
coconuts, thus
deriving their
popular name.