Transcript Mandibulate Arthropod Characteristics

PHYLUM
ARTHROPODA
Arthropoda Characteristics
• account for 80% of all living animal species
Arthropoda Characteristics
• means “jointed foot”
• eucoelom
• exoskeleton made of chitin
– cuticle of organism
• show a high degree of cephalization
– variety of segmented appendages around mouth serve as
sensors and food handlers
– most have compound eyes & other light sensing structures
• cuticle inhibits growth causing organism to shed
– reason for molting
• body plan of repeated segments that attach to an
appendage
Arthropoda Characteristics
• open circulatory system
– Heart pumps circulatory fluid thru vessels
that empty into spaces in the body
• nervous system is ladder-like with brain
formed from fused ganglia
• respiratory & circulatory systems vary
depending on species
Evolutional & classification
• Evolved from a common ancestor
• Biologists are uncertain about the order in which subgroups of arthropods
evolved & the exact relationships between the subgroups
• Similar characteristics of many modern subgroups may be the results of
convergent evolution (process by which unrelated species become more
similar as they adapt to the same kind of environment)
– EXAMPLE: TRILOBITES ~ancient & extinct
– Had many body segments & one pair of appendages on each segment
Evolution & classification….continued
• Most living arthropod species have some segments
that lack appendages and some segments that are
fused into a larger structure called a tagma
(tagmata, plural)
• Tagmata tend to be specialized for functions like
feeding, locomotion & reproduction.
REVIEW QUESTIONS
• 1. Identify the type & composition of an
arthropod’s skeleton.
• 2. What is convergent evolution? <IN YOUR
OWN WORDS>
• 3. Explain how arthropods are highly
cephalized.
• 4. What is a tagma? Plural form is ___.
• 5. What are they specialized for?
Domain
Eukarya
Kingdom
Animalia
SUBPHYLUM
EXAMPLES
CLASSES (just common
classes are listed) Broken
down
Trilobitomorpha
Trilobites
*Trilobita
trilobites
Chelicerata
Spiders, Scorpions,
Horseshoe crabs
*Arachnida
spiders & scorpions
ticks & mites
*Merostomata
horseshoe crabs
Myriapoda
Centipedes, Millipedes
*Chilopoda
centipedes
*Diplopoda
millipedes
Bees, Beetles, Crickets,
Grasshoppers, Wasps,
Butterflies, Moths….
*Insecta
insects
Brine shrimp, Barnacles,
Shrimp, Crabs, Lobsters
*Malacostraca
PHYLUM
Hexapoda
ARTHROPODA
Crustacea
Lobsters, crabs, crayfish,
shrimp, shrimplike krill
*Maxillopoda
barnacles
*Brachiopoda
DIVISIONS of Arthropoda
• Divided into 5 major subphyla
• Based on development in the structure of
appendages, such as mouth parts
• 2 major types of mouth parts : <sketch >
1. Mandibles (jawlike) Fig 1
2. Chelicerae (pincerlike) Fig 2
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2
Mandibulate Arthropod Characteristics:
Mouthparts are mandibles normally chewing sideways
One or two pairs of antennae
Various body region
arrangements - cephalothorax
& abdomen / head & trunk /
head, thorax & abdomen
Variable leg numbers
Insects, crustaceans &
myriapods
mandibles
Chelicerate Arthropod Characteristics:
Pincher-like mouthparts chelicerae - and pedipalps
NO antennae
Two body regions, usually
- cephalothorax &
abdomen
Four pairs of legs
Horseshoe crabs and
arachnids are only living
groups
5 subphyla
1.
2.
3.
4.
5.
Trilobitomorpha
Chelicerata
Myriapoda
Hexapoda
Crustacea
CHARACTERISTIC
Mouthparts
Antennae
Body arrangement
Leg #
Examples
MANDIBULATE
ARTHROPODS
CHELICERATE
ARTHROPODS
Review Questions .. Add to ?s page
• 7. What major characteristic is used to divide
arthropods into groups?
• 8. ID 2 major types of mouth parts, describe
them & sketch a picture.
• 9. ID 3 groups of mandibulate arthropods.
• 10. ID 2 living groups of chelicerate
arthropods.
• 11. Identify the 5 subphyla of phylum
Arthropoda.
Subphylum Trilobitomorpha
• Trilobites
• Most primitive of all arthropod groups
• Well-known fossil group of
marine arthropods
EXTINCT
Subphylum Chelicerata
• Chelicerates including spiders, mites, scorpions,
mites, and horseshoe crabs
• Lack antennae
• Typically have 6 pairs of appendages
• First pair of appendages, the chelicerae, are
modified into pincers or fangs
• Classes:
– Arachnida: spiders, scorpions, mites, ticks
– Merostomata: horseshoe crabs
CLASS ARACHNIDA
Spiders, scorpions, mites, ticks
Body divided into cephalothorax & abdomen
Cephalothorax usually bears:
*6 pairs of jointed appendages
*1 pair of chelicerae
*one pair of pedipalps (aid in
holding/chewing)
*4 pairs of walking legs
Mite vs Tick Body Regions
pedipalps &
chelicerae
cephalothorax
abdomen
Mite vs Tick
• Ticks are usually larger
• Ticks are ectoparasites (live on
the outside of a host to survive)
• Mites are smaller
• Mites are more diverse & found in
more habitats
• Mites are more free-ranging
predators
American dog tick female laying egg mass (1000-2000 eggs!).
American dog tick male
Blacklegged (deer) tick female
DEER TICKS can do this…..
• This photograph shows the “bull’s-eye rash” that
often manifests at the site of a tick bite when the
Lyme disease bacterium is transmitted.
REMOVING TICKS…FYI
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Should you find a tick that has embedded its mouthparts in the skin, remove it as soon as possible
using these tips from the Centers for Disease Control:
Use fine-tipped tweezers or a notched tick extractor, and protect your fingers with a tissue, paper
towel or latex gloves. Avoid removing ticks with bare hands.
Grasp the tick as close to the skin surface as possible and pull upward with steady, even pressure. Do
not twist or jerk the tick; this may cause the mouthparts to break off and remain in the skin.
After removing the tick, disinfect the bite site and wash your hands with soap and water.
Do not squeeze, crush or puncture the tick’s body because its fluids may contain infectious organisms.
Skin accidentally exposed to tick fluids can be disinfected with iodine scrub, rubbing alcohol or water
containing detergents.
Save the tick for identification in case you become ill. This may help your doctor make an accurate
diagnosis. Place the tick in a sealable plastic bag and put it in your freezer.
Don’t use petroleum jelly, hot matches or other folk remedies as these may cause a tick to release
additional saliva or gut contents, increasing chances of infection.
While tick bites can cause problems, those problems are relatively rare. Don’t stop enjoying nature,
the great outdoors and your favorite warm-weather activities because you’re fearful of tick bites. Just
be sure to protect yourself first and do tick checks after being outdoors.
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DON’T MASH THE TICK WHILE IT IS ATTACHED!!
Ticks on a black iguana!!!!!
Clover mites
Twospotted spider mites
Predatory mite
Spider Anatomy
pedipalp
chelicera (fang)
cephalothorax
narrow waist
abdomen
Spider Anatomy
• Chelicerae are modified as fangs to inject venom
• Venom is produced in poison glands in cephalothorax & flow
thru ducts to fangs
• Most have 8 simple eyes/each with single lens
• 3 pairs of spinnerets on tip of abdomen (made of microscopic
tubules connected to silk glands)
• Respiratory system=book lungs (paired sacs in abdomen that
are folded like pages of a book) *not all have these
• Trachea-system of tubes that carry air directly to tissues from
openings in exoskeleton known as spiracles *not all spiders
have these
• Some spiders have both book lungs & tracheae
• Malpighian tubules=main excretory organs that help conserve
water in terrestrial environments
Black widow with egg case
Brown recluse
Class Arachnida
BROWN RECLUSE
*has violin-shaped mark on
dorsal surface of cephalothorax
*aka “violin spider”
*venom kills & digests the
tissues surrounding the bite
*necrosis=tissue death
*bite is often not felt
immediately
*bite is rarely fatal but causes
pain
Neck of violin
head of violin
BLACK WIDOW
*female has bright red or
orange mark shaped like
an hourglass
on ventral surface of
stomach
*animals most at risk from BW bite: insects & male
BW (females often eat the males after mating)
*bite to humans is rarely fatal
http://www.medicinenet.com/black_widow_brown_recluse
_pictures_slideshow/article.htm
Wolf spider with egg case
Tarantula
Spitting spider
Orb-weaving spider
Most poisonous spider in the
world
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https://www.youtube.com/watch?v=pQYWBmk_V2g
Brazilian
Wandering Spider
The Brazilian Wandering Spider
Central/South America –roam jungle floor at night
Aka Banana spider
When threatened they stand erect with their front legs drawn
into the air and rock back and forth -> considerations for
using venom to treat Erectile Dysfunction
Camel Spider..
not poisonous to humans
http://www.camelspider.org/
• Aka sun scorpions but they try to avoid
sunlight
• Among fastest of the arthropods
• They are not spiders and are not scorpions
• 2 families in North America: desert,
grasslands, and beach dunes
• Not dangerous or venomous to humans-what
can hurt you is the bacteria on their
mouthparts
• Carnivores=use huge chelicerae to kill small
rodents, spiders, insects, termites & small
reptiles
Camel spider…in desert
10 most poisonous spiders
Scorpion differ from spiders because
they ….
• Have large,
pincerlike
pedipalps which
they hold in a
forward position
• Have segmented
abdomen with a
large stinger on the
last segment
World’s Largest Spider
• Giant Huntsman Spider
• Considered this because of 12” leg span
• Southeast Asia
Giant Huntsman Spider
• Discovered 2001
• Confused w/tarantulas b/c they are big and
hairy
• Differentiate them by crablike legs that allow
side to side movement making them very fast
and hard to catch
• Life span 2 years
• Females are very protective of young and can lay
200 eggs
• Relocate spider if found because spiders are
important to ecological environment (food
chain)
• Don’t normally build webs b/c they actually
hunt and attack their prey
2nd largest spider https://www.youtube.com/watch?v=ri5BQdUR
q9k
Goliath Bird-eating Spider
• In tarantula family
• Males-3-6 years/females 15-25 years
• Leg span of up to 12” and can weigh up to 60
ounces *can be classified as largest spider by
MASS
• Has been witnessed eating a hummingbird
• Fairly harmless to humans
• diet primarily consists of insects& other
invertebrates but has been known to kill &
consume rodents, lizards, bats and even deadly
venomous snakes
• Native to rain forest of South America
• Found burrowing in marshy, swampy areas
• Population is threated due to rain forest
destruction
Class Merostomata
• Live primarily in shallow ocean waters or on soft
sandy or muddy bottoms
• Will come on shore for
mating
• Commonly used as bait to
fish for eels and whelk and
in fertilizer
• Numbers are declining
because of coastal habitat
destruction &
overharvesting along the
East coast of North America
Saving Horseshoe Crabs
Review Questions # 3…add to pg 13
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12. What is the most primitive of all arthropod groups?
13. Describe the 1st pair of appendages of chelicerates.
14. Identify the 6 pairs of appendages of an arachnid.
15. Which is larger—tick or mite?
16. What is an ectoparasite?
17. What body region contains the poison glands of
spiders?
18. Why should you not squeeze a tick?
19. Differentiate the markings of a black widow and
brown recluse.
20. How do scorpions differ from spiders anatomically?
21. Why is the horseshoe crab population declinging?
Subphylum Myriapoda
•many legged arthropods
•all have one pair of antennae, a head region, and trunk with
many pairs of legs
•use trachea
Diplopoda - millipedes
Chilopoda - centipedes
Myriapods
[one pair of antennae, head & trunk regions, trunk with many pairs of legs]
Millipede (Diplopoda)
Two pair of legs per visible segment, attached
under body.
Centipede (Chilopoda)
Pair of fangs under head, one pair legs per visible
segment - attached to side of body.
No fangs, no eyes, legs attached to side of body.
Scolopendra
• Galapagos Centipede
• Scolopendra
galapagoensis
• Largest centipede
• 44-46cm
• Amazon Centipede
• Scolopendra gigantea
• Habitat distribution:
Brazil, Ecuador, Peru,
the Amazon River
Basin countries and
regions
“LEGS”
African Giant Black Millipede
(Archispirostreptus gigas)
• Tanzania, Africa – "Legs," one of the
world's largest millipedes, these guys
grow to be 10-12" long with 600 wiggly
legs. Think of them like the world's
largest roly-poly! They won't bite, pinch
or sting – but are very impressive! Great
for all ages.
SUBPHYLUM CRUSTACEA
• VERY DIVERSE GROUP
• LOBSTERS, CRAYFISH, SHRIMP, KRILL,
BARNACLES ARE MOST COMMON
• Characteristics:
Most are aquatic (majority marine)
two pairs of antennae
a pair of mandibles
a pair of compound eyes (usually on stalks)
and two pair of maxillae on their headsfollowed
by a pair of appendages on each body segment
– crustacean bodies usually are made up of head,
thorax, and abdomen, although the segments
composing these tagmata differ among different
Classes)
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CLASS MALACOSTRACA
• EX: LOBSTERS, CRABS, SHRIMP, CRAYFISH
• LARGEST CLASS OF CRUSTACEA
• DISPLAY GREATER DIVERSITY OF BODY
FORMS THAN ANY OTHER CLASS OF
ORGANISMS
• ABUNDANT IN MARINE ECOSYSTEMS
• VIRTUALLY EVERY FEEDING HABIT IS
EXHIBITED BY SOME MEMBER OF THIS CLASS
FROM PREDATOR TO PARASITE TO FILTER
FEEDER (RARE)
JAPANESE SPIDER CRAB
12 FEET
SPAN IN
LEGS 41 lbs
http://www.youtube.c
om/watch?v=rh5W0Sy
rWyg
Class Maxillopoda
• BARNACLES
• *sessile
• *marine – shallow and tidal waters
• *feed by straining suspended matter and food
particles from water, typically by passing the
water over a specialized filtering structure
http://www.youtube.com/watch?v=25F7xMVN
t-w BARNACLE FEEDING
Class Brachiopoda
• Brine shrimp
• Very primitive
• Can live in water with high salt concentration
(salinity)
• Some species are on endangered species list
Review Questions Set 4
• 22. Give a general body description of
members of subphylum Myriapoda.
• 23. Id the most common examples of
subphylum Crustacea.
• 24. Give 5 body characteristics of crustaceans.
• 25. What is the largest class of Crustacea?
• 26. What class has the most diverse body
form of all classes of animals?
• 27. Describe the feeding method of barnacles.
• 28. What is a unique characteristic of
brachiopods?