Transcript Test #2 Material

Test #2 Material
Phylum: Arthropoda
Phylum: Arthropoda (Crustaceans,
Spiders, and Insects
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General Characteristics
Exoskeleton is segmented and has jointed
appendages
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Exoskeleton
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internal skeleton made of chitin and protein
can be thick and hard, or paper thin and flexible
for protection and the attachment of muscles
impermeable to water and strong
Molting
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must shed the exoskeleton in order to grow another one
leaves the animal temporarily vulnerable to other animals
Arthropoda
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Sense and smell
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has eyes, olfactory
receptors, and antennae
(touch and smell)
Open Circulatory System
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fluid inside is called
hemolymph (blood is the
term to describe fluid in a
closed circulatory system)
hemolymph is pumped by
the heart into small arteries
then into sinuses
the fluid re-enters the heart
through pores
Early Arthropods
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The earliest
Arthropod were the
trilobites. They lived
in shallow seas.
Class Arachnida (scorpions, spiders,
and ticks)
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Nearly all ticks are blood
sucking parasites
Mites live on a wide variety of
hosts including other
arthropods
Have a cephalothorax with
six pairs of appendages
 Chelicerae
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fangs with poison (used
to attack prey and chew)
Pedipalps
4 pairs of walking
appendages
Spiders
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Gas exchange (breathing) is
done by using a book lung.
 Stacked plates that
exchange oxygen and
carbon dioxide between
the hemolymph and air
Silk webs are strung to catch
prey (produced by abdominal
glands called spinnerets)
 Webs are different
according to the species,
and are always perfect on
the first try.
 Webs are also used for
escaping predators and to
wrap the eggs.
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alimentary canal (yellow)
blood vascular system (red)
breathing system (orange)
nervous system (blue)
excretion system (green)
reproduction system (white)
set of silk glands (white at the
rear)
Feeding
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As a spider chews, it
spills digestive juice
onto the torn tissue,
then sucks up the
liquid meal. –Yummy.
Other Classes
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Class Diplopoda
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Millipedes
Wormlike with legs (2 pairs per segment)
Not 1000 legs
Eat decaying leaves and plant matter
Class Chilopoda
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Centipedes
Carnivores
Head has antennae
3 pairs of appendages (not legs)
Jaw-like mandible
2 legs per segment
Have poison claws that paralyze prey and help with defense
Class: Insecta
Outnumber all other forms of life
combined
 Live in every terrestrial habitat and in
fresh & salt water
 26 orders of insects
 Entemology- study of insects
 The earliest insect fossil is from 400mya
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Insecta Body Structure
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Many have 1 or 2 pairs of wings that
are an extension of the body (not
appendages)
 Birds and bats have modified legs and
arms for wings
 Dragonflies are thought to be the first
to fly
 Bees, butterflies, and wasps have
wings that are hooked together and
move as a pair
 Beetles use the top half of their wings
for protection on the ground and the
bottom half to fly
Internal Insect Anatomy
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Body has 3 regions
Head-1 pair of
antennae and one
pair of compound
eyes
Thorax- 3 pairs of
walking legs
Abdomenabdominal region
Physiology
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Open circulatory system (hemolymph)
 Breathe through a tracheal system
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Branched, chitin lined tubes that carry oxygen
directly to the cells
Opens to the outside through
Spiracles-pores that open and close to
regulate air flow and limit water loss
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Nervous system has a pair of ventral nerve cords that
meet in the head at the cerebral ganglion (brain)
Growing happens in two separate
ways
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Incomplete Metamorphosis
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Complete Metamorphosis
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Young resemble adults but
are smaller
Series of molting occurs until
it is an adult
Grasshoppers
Complete Metamorphosis
Maggots, grubs, and
caterpillars
Larval stages
Larva -> Pupa -> Adult
Usually reproduce sexually
Crustaceans (Lobsters, shrimp,
crab, and crayfish)
Have 2 pair of antennae
 3 or more pairs of mouth parts
 A lost appendage can be regenerated
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Phylum: Chordata
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Two existing classes
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Chondrichthyes
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Cartilagenous fish
14 orders
50 families
810 species
Ostiechthyes
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Bony fishes
46 orders
437 families
23,500 species
Class: Chondrichthyes
•Sharks, skates, rays
•Cartilaginous – they have relatively flexible
endoskeletons made of cartilage instead of bone
•Started with real bones, evolved to cartilage
•Jawed and paired fins
•Respiration by 5-7 gill slits on both sides of their pharynx
•No swim bladder or lung
•Very dense and sinks if it stops swimming
•This helps with breathing; water constantly passing
over gills
•Rest on sea floor pump water through body with jaw
muscles
Reproduction
•Eggs are fertilized internally
•Male has claspers on pelvic fins that transfer sperm to
female
•Oviparous – lay eggs that hatch outside mother’s
body
•Ovoviviparous – eggs hatch in uterus and the babies
come out after. Nourishment from eggs
•Viviparous – young develop in uterus and then are
born. Nourishment comes from mom
•Reproductive, excretory, and digestive systems all
empty into a chamber called a cloaca, then it is emptied
through a single vent
Sharks
•Largest sharks are (plankton) filter feeders
•Most are carnivores
•Swallow prey whole or use powerful jaws and
sharp teeth to tear prey into chunks
•Teeth probably evolved from scales
•Continually shed and replace teeth
•Tough leathery skin is covered with toothlike, dermal
placoid scales arranged to reduce the turbulence of
water flowing along the body surface
•Short digestive tract
Senses
•Eyes are lidless
•Behind each eye is a spiracle – remnant of the first
gill slit
•Sharp vision, but can’t see colors
•Nostrils open into dead end cups (smell not
breathing)
•Can detect electrical fields caused by muscle
contractions of other animals
•Ampullae of Lorenzini – electroreceptors located on
the sharks head
•Lateral line – runs along side, detects changes in
water (minor vibes)
•No eardrums – whole body receives sound waves
through water
•Detect prey from a kilometer or more away with
their large olfactory organs
•Skates and Rays
•Are mainly bottom dwellers
•Flattened teeth suitable for crushing hard shelled
prey
•Enlarged fins that extend onto the side of the head
•Manta Ray – largest species
•Venom gland in the tail of stingrays probably helps to
deter predators
•Some rays have electric organs in the tail or fins that
can stun prey with as much as 200 volts of electricity
•Their eyes and spiracles (openings for taking in
water) are located on top of the head, allowing
them to take in water for gill ventilation while being
partially buried in sand
•Skates normally have prominent dorsal fins while
those of rays are absent or reduced in rays
Skate
Ray
•Chimaeras
•Sometimes called a ratfish
•Feed mostly on mollusks
•Venom gland in front of the dorsal fin
•Diverged from sharks
Class Osteichthyes
•Bony fish
•Marine and fresh water habitat
•Size ranges from 1cm to 6m long
•Make up all but 4% of fish species
•Bony fish have passed through several stages making
the following changes:
1. A completely ossified internal skeleton with a
stronger cranium
2. The transformation of the air-breathing lungs
into a buoyancy-compensating device called a
swim bladder.
3. The transformation of the asymmetrical
heterocercal tail (seen in sharks and some
primitive bony fishes) into the symmetrical and
more efficient homocercal tail
4. The development of thin cycloid scales and
ctenoid scales from the thicker ganoid scales
5. The loss of spiracles, development of stout spines
in the fins and more efficient jaws
•Outside
•Skin is covered by flat, bony scales
•Glands in skin secrete a mucus (slimy) to reduce
drag while swimming
•Lateral line – detects changes in water
•Respiration
•Draw water over 4 or 5 pairs of gills
•Gills are protected by operculum
•Water to mouth to pharynx to gills by movement of
the operculum
•Helps fish breath when stationary
•Swimming
•Swim Bladder – air sac that helps control the
buoyancy of fish
•Gasses go back and fourth between the blood and
swim bladder
•Helps fish conserve energy by staying still
•Flexible fins for maneuvering and propulsion
•Fastest fish can swim in short bursts up to 80mph
•Reproduction
•Most are oviparous – lay eggs and fertilized
externally
•Scales
•Cycloid
•Thin and overlapping permitting more flexibility
•Grow as the fish grows, and in some species,
show annual growth rings
•Found in the primitive bowfin and many teleosts
•Ctenoid
•Ctenoid scales are essentially cycloid scales
with teeth at their posterior edges
•It is thought that these teeth help to reduce
hydrodynamic drag during swimming
•Found in many teleosts
•Ganoid
•Thick and non-overlapping
•Composed of bone overlaid with an enamellike substance called ganoin
•This type of scale is also seen in the lobedfinned coelacanth
•3 Lineages of Bony Fishes
1. Ray-Finned Fishes
•Most familiar to us
•Fins are supported by long rays or spines
•Light flexible scales that don’t hamper motion
•Example: Teleosts – salmon, tuna, rockfish,
catfish, perch, moray eels, flying fish,
scorpionfish and bass, trout, herring
Gar
2. Lobe-Finned Fishes
•7 species
•Paired fins that incorporate fleshy extensions
from the body
•May have used lobes to waddle onto land
•Have not evolved much
3. Lungfishes
•Live in deep sea off Madagascar
•Have actual lungs and come to surface to gulp air