Calendar
Contact Teacher
Labs:
nothing
nothing
nothing
Links
Notes:
Animal Body
Arthropods
Biochem
Cell Cycle
Cell Interactions
Cell Structure
Circulation
Respiration
Communities
Digestion
DNA
Ecosystems
Energy
Evolution Evidence
Future of
Biosphere
Genetic Engineering
Gene Function
Genetics
Hormones
Human Evolution
Immunity
Species
Interaction
Kidneys
Locomotion
Membranes
Mollusks
Mutation
Nervous
Non-Coelmic
Photosynthesis
Plant Physiology
Population Genetics
Population
Dynamics
Cellular Respiration
Sensory
Speciation
Taxonomy
Vertebrates
Vertebrate
Org
Vocabulary:
1,2,3,4,5,6,7,8,9,10,
11,12,13,14,15,
16,17,18,19,20,
21,22,23,24,25,
26,27,28,29,30,
31,32,33,34,35,
36,37,38,39,40,
41,42,43,44,45,
46,47,48,49,50,
51,52,53,54
Arthropods
I. Introduction
A. Development of Jointed Appendages
1. First accomplished by the arthropods
2. Necessary adaptation with advent
of rigid exoskeleton
B. Success of the Arthropods
1. Includes nearly two-thirds of all
named species on earth
2. May include 30 million species
of insects alone
3. Are abundant in all habitats, but
dominate terrestrial regions
C. Economic Importance
1. Cause extensive damage to food
crops
2. Are important human food source
3. Pollinate crops, control insects
and weeds
4. Produce products like silk and
honey
5. Critical importance in recycling
organic matter
II. General Characteristics Of Arthropods
A. Possess Characteristic Jointed Appendages
1. Phylum name means "jointed
feet"
2. Appendages modified into antennae,
mouthparts and legs
B. Other External Characteristics
1. Bodies are segmented
a) Some members
have large numbers of segments
b) In others the
segments are fused into functional units: tagma
c) Process called
tagmatization
d) Segmentation
may be more obvious during development of larvae
e) Head and thorax
may be fused into a cephalothorax
2. Have rigid external skeleton:
exoskeleton
a) Immature forms
may not resemble adult form
b) May change characteristics
in metamorphosis from egg to adult
3. Members are generally small in
size
III. Major Groups Of Arthropods
A. Primarily Categorized by Modifications of Anterior
Appendages
1. Mandibulates have modified mandibles
a) Anterior, but
not the most anterior appendages
b) Include crustaceans,
insects, centipedes, millipedes
c) Most anterior
appendages are sensory antennae
2. Chelicerates lack mandibles and
instead possess chelicerae
a) Include spiders,
mites, scorpions
b) Evolved from
very most anterior appendages
c) May appear as
pincers or fangs
B. Secondarily Categorized Anatomy of All Appendages
1. Aquatic mandibulates
a) Appendages are
biramous (two-branched)
b) Typical of crustaceans
c) Possess nauplius
larva
2. Terrestrial mandibulates
a) Appendages are
uniramous (one-branched)
IV. Typical of insects, centipedes, millipedes
a) Also characteristic
of phylum Onychophora
2. Mandibles evolved independently
in terrestrial and aquatic mandibulates
3. Mandibulates and chelicerates evolved
independently, neither gave rise to other
a) Second chelicerate
appendages are pincer or feelerlike, followed by legs
b) Chelicerae resemble
other chelicerate appendages more closely than mandible resemble other
mandibulate appendages
V. External Features
A. Exoskeleton
1. All arthropods covered by hardened
skeleton or cuticle
a) Tough outer covering
is secreted by and fused with epidermis
b) Varies in toughness
and thickness
c) Crustaceans add
calcium carbonate, making it less flexible
2. Functions of exoskeleton
a) Prevents excessive
water loss
b) Protects from
predators, parasites and injury
3. Growth requires periodic ecdysis
a) New exoskeleton
grown beneath old one
b) Controlled by
hormones
c) Separated by
a fluid that dissolves components of old skeleton
d) Old skeleton
cracks open and is shed
e) New skeleton
is initially quite soft and must be expanded to full size
f) Hardens with
exposure to air or water
B. Compound Eye
1. Composed of many ommatidia: independent
visual units
a) Each covered
with a lens
b) Linked to eight
retinula cells and central light-sensitive rhabdom
2. Apposition eyes
a) Example: bee
b) Each ommatidium
acts in isolation
c) Surrounded by
pigment cells
d) An image inverted
on each ommatidium retina
e) Individual images
formed in brain
3. Superposition eyes
a) Example: moth
b) Images from ommatidia
are combined on cornea at rear of eye
c) Not associated
with pigment cells
d) Single right-side-up
image is formed
4. Ocelli are simple eyes with single
lenses
a) Sometimes occur
together with compound eyes
b) Function in distinguishing
light and darkness
c) May also serve
as horizon detectors in locusts and dragonflies
VI. Internal Features
A. Reduction of Coelom Through the Course of Evolution
1. Consists of cavities housing reproductive
organs and some glands
2. Arthropods completely lack cilia
3. Have tubular gut that extends from
mouth to anus
B. Circulatory System
1. Open system, no closed blood vessels
2. Longitudinal heart along dorsal
thorax and abdomen
a) With contraction,
blood flows into head
3. When heart relaxes blood returns
it
a) Series of one-way
valves in posterior of heart allows blood to flow inward only
b) Blood from anterior
end flows through spaces to posterior end
c) Flow is more
rapid with greater activity
d) Blood delivers
nutrients, transports wastes
C. Respiratory System
1. Functions to transport oxygen directly
to tissues
2. All parts of body must be near
air passage limiting body size
3. Possess no single respiratory organ,
but a system of branched tracheae
a) Become smaller
tracheoles that are in contact with individual cells
b) Air passage controlled
through external spiracles
c) Closing spiracles
conserves water
d) Airflow assisted
by muscular movements in larger organisms
4. Many chelicerates have book lungs
or book gills
a) A series of leaflike
plates within a chamber
b) Air drawn in
and out by muscular contractions
5. These respiratory systems unique
to arthropods and Onychophora
6. Crustaceans have typical gills
D. Excretory System
1. Several forms of excretory systems
2. Principal components of the land
mandibulate are Malpighian tubules
a) Slender projections
of the digestive tract
b) Located at the
junction of the midgut and hindgut
c) Fluid of blood
passes through walls of tubules
d) Nitrogenous wastes
are precipitated as fluid passes toward hindgut
e) Waste emptied
into hindgut and eliminated
f) Most water and
salts reabsorbed by hindgut and returned to body
E. Nervous System
1. Predominant double chain of ganglia
runs along ventral surface
2. Anterior end possess three fused
pairs of dorsal ganglia: the brain
3. Much control of activities regulated
by ventral ganglia
a) Many activities
continued with brain removed
b) Brain appears
to be inhibitor, not stimulator as in vertebrates
VII. Subphylum Chelicerata: The Chelicerates
A. Class Arachnida: The Arachnids
1. Largest class of chelicerates
2. Possess a pair of chelicerae, pair
of pedipalps, four pair of legs
a) Chelicerae:
frontmost appendages, fangs with poison glands
b) Pedipalps: next
set of appendages, like legs but one less segment
c) Have specialized
functions: copulatory organs, sensory organs
3. Other general characteristics
a) Most are carnivorous,
mites are herbivorous
b) Most ingest only
preliquified foods, thus digestion is external
c) Are generally
terrestrial, evolved direct transfer of sperm
d) Breathe by trachea,
book lungs or both
e) Include 11 orders
4. Order Scorpiones: the scorpions
a) Pedipalps are
modified into pincers
b) Use pincers to
handle and tear food apart
c) Have venomous
stingers on terminal segment
d) Distinctive jointed
abdomens
e) Extremely ancient
group of terrestrial arthropods
f) Respiration via
book lungs
g) Males deposit
spermatophores, picked up by females
5. Order Araneae: the spiders
a) Hunt prey or
catch it in webs
b) Silk formed from
fluid protein, forced out spinnerets
(1)
Modified appendages
(2)
May be up to six pairs
c) Many forms are
active hunters
d) Have poison glands
leading through chelicerae
(1)
Some are poisonous to man and large mammals
(2)
Examples: black widow and brown recluse
e) Reproduction
(1)
Males produce sperm web, add drop of sperm, pick up with pedipalps
(2)
May involve elaborate courtship
(3)
Male fits pedipalps into special plate on female's abdomen
(4)
Female may eat male once fertilization is complete
(5)
Eggs enclosed in silken egg sac
(6)
Young resemble adults, go through several molts
6. Order Acari: the mites
a) Most diverse
in terms of numbers and species
b) Generally very
small in size
c) Cephalothorax
and abdomen fused into an ovoid body
d) Respiration occurs
through trachea or directly through exoskeleton
e) Development occurs
on many complex successive stages
(1)
Various juvenile stages have become reproductive
(2)
Called paedomorphosis
f) Many live on
humans, some transmit diseases
g) Ticks are blood-feeding
ectoparasites, transmit various diseases
h) Cause extensive
plant damage
i) Some are valuable
biological controls
7. Order Opiliones: the daddy longlegs
a) Possess compact,
oval bodies with extremely long, slender legs
b) Respire by a
single pair of trachea
c) Engage in direct
copulation, unusual among arachnids
(1)
Males possess penis
(2)
Females use ovipositor to deposit eggs
d) Most are predators,
some are scavengers or feed on plant juices
B. Class Merostomata: The Horseshoe Crabs
1. Example: Limulus, common on North
Atlantic coasts
2. Evolution
a) Ancient group,
fossils identical to 220 million years old Limulus
b) May be derived
from trilobites
3. Reproduction
a) Live in deep
water, migrate to shallow coastal waters to mate
b) External fertilization,
larvae resemble trilobites
4. General biology
a) Feed at night
on mollusks and annelids
b) Swim on backs
by moving abdominal plates
c) Possess five
pairs of walking legs
d) Protective shell
ends in tail spine, the telson
e) Breathe via five
pairs of book gills
C. Class Pycnogonida: The Sea Spiders
1. Common, but rarely observed because
of small size
2. Adults are generally parasites
or predators on other animals
3. General biology
a) Have sucking
proboscis with terminal mouth
b) Body consists
mostly of cephalothorax, no well-defined head
c) Possess four
to six pairs of legs
d) Males exhibit
parental care of young, carry eggs on legs
e) Lack excretory
and respiratory systems, exchange by diffusion
4. Not closely related to other two
classes
VIII. Subphylum Crustacea: Crustaceans
A. Arrangement and Nature of Appendages
1. Two pairs of antennae, three pairs
of chewing appendages
2. Number of legs varies with the
species
3. All are biramous
a) Excluding first
pair of antennae
b) Single-branched
appendages previously biramous, one branch lost in evolution
4. Evolution of crustaceans
a) All descended
from common ancestor as evidenced by nauplius larvae
b) Some groups lack
larvae and undergo direct development into adult
B. General Biology
1. Have legs on abdomen and thorax
like millipedes and centipedes (unlike insects)
2. Only arthropods with two pair of
antennae
3. Mandibles evolved from limbs that
developed a chewing function
4. Many have compound eyes and tactile
hairs over whole body
5. Have feathery gills near base of
legs
6. Excretion of nitrogen wastes occurs
mostly across surface of cuticle
7. Osmotic composition of blood regulated
by labyrinth or green gland
a) Diversity of
Crustaceans
8. Decapods ("ten-footed")
include lobsters, shrimp and crabs
a) Exoskeleton reinforced
with calcium carbonate
b) Body segments
fused into cephalothorax, covered by carapace
c) Crushing pincers
common, used to obtain food
d) Abdominal swimmerettes
used in reproduction and locomotion
e) Snapping of telson
and uropods causes forceful, rapid movements
f) Crabs have larger
broader carapace than lobsters
g) Shrimps have
smaller carapace than crabs or lobsters
9. Terrestrial crustaceans
a) Pillbugs and
sowbugs, terrestrial isopods, order Isopoda
b) Sand and beach
fleas, order Amphipoda
10. Planktonic crustaceans
a) Copepods, order
Copepoda
b) Water fleas,
order Cladocera
c) Ostracods, order
Ostracoda
d) Fairy shrimp
and brine shrimp, order Anostracoda
1 1. Barnacles, order Cirripedia
a) Are sessile as
adults, but have free-swimming larvae
b) Head attached
to submerged object, food swept into mouth by feathery legs
c) Protected by
calcareous plates attached to substrate
d) Are hermaphroditic
which is unusual for crustaceans
IX. Subphylum Uniramia
A. General Characteristics
1. Evolved from annelids similar to
oligochaetes, related to Onychophora
2. Respire via trachea
3. Filter waste products through Malpighian
tubules
B. Classes Diplopoda and Chilopoda: The Millipedes
and Centipedes
1. Both possess head region followed
by numerous segments
2. Share similar reproductive strategies
a) Fertilization
is internal, direct transfer of sperm
b) Sexes separate,
all species lay eggs
c) General appearance
of young is similar to adult
3. Centipedes
a) Have one pair
of legs per segment
b) Are carnivorous,
eat mainly insects
c) Appendages of
first trunk segment modified into poison fangs
4. Millipedes
a) Have two pairs
of legs per segment
b) Each segment
derived from two fused segments
c) Most are herbivorous
d) Can roll bodies
into a flat coil
e) May secrete defensive
fluids and cyanide gas
C. Class Insecta: The Insects
1. Largest group of organisms on earth
a) Especially numerous
in the tropics
b) Enormous diversity
2. External features
a) Primarily terrestrial
organisms, small in size
b) Have three body
segments: head, thorax, abdomen
c) Have three pairs
of legs, all attached to thorax
d) Have one pair
of antennae
e) May have one
or two pairs of wings
f) Most possess
compound eyes, many have ocelli
g) Elaborate mouthparts,
widely variable
(1)
Characterized by unsegmented mandibles
(2)
Segmented maxillae comprise secondary pair of mouth parts
(3)
Labium forms the lower lip
(4)
Labrum forms the upper lip
(5)
Chewing insects have a tonguelike hypopharynx
3. Orders classified by structure
of mouthparts, feeding habits
a) Chewing or mandibulate
mouthparts
(1)
Coleoptera = beetles
(2)
Hymenoptera = bees, wasps and ants
(3)
Isoptera = termites
(4)
Orthoptera = grasshoppers and crickets
b) Elongate, stylet-like
mouthparts
(1)
Diptera = horseflies, blackflies, mosquitos have fused stylets
(2)
Advanced flies have piercing or lobe-like labium
(3)
Lepidoptera = moths, butterflies have coiled proboscis
4. Thorax consists of three fused
segments (tagmata)
a) Each has a pair
of legs
b) Legs may be absent
in some larvae
(1)
Example: bees
(2)
Example: flies
5. Structure of insect wings
a) If two pairs,
attach to middle and posterior segments
b) If one pair,
attach to middle segment
c) Arise as saclike
outgrowths, are solid excluding veins
d) Are not homologous
to other appendages
e) Two pairs are
the basic construction for winged insects
f) One pair lost
in the evolution of groups like flies
g) Most wings folded
at rest, except for outstretched dragonfly wings
h) Forewings may
be hard and tough, form covering for hindwings
(1)
Example: beetles
(2)
Example: grasshoppers and crickets
i) May possess detachable
scales, like butterflies and moths
j) Some groups like
springtails never evolved wings
k) Other insects
are derived from winged ancestors
(1)
Fleas
(2)
Lice
6. Internal organization
a) Tubular, somewhat
coiled digestive tract
(1)
Greater coiling associated with sucking mouthparts
(2)
Dilute digestive enzymes less effective on liquids than solids
(3)
Anterior and posterior digestive regions lined with cuticle
(4)
Digestion occurs within stomach or midgut
b) Excretion through
Malpighian tubules
c) Trachea extend
throughout body, may form air sacs
d) Spiracles are
permanently closed in some aquatic, parasitic forms
e) Fat body is food-storage
organ or is similar to vertebrate liver
7. Sense receptors
a) Possess wide
variety of sensors in addition to eyes
b) Sensory hairs
located all over bodies
c) Sense of taste
located on mouthparts
d) Sense of smell
located on antennae
e) Sound detected
by tympanum, associated with tracheal air sacs
f) Sensory hairs
may also detect sound waves
8. Insect communication
a) Produce sounds
which are mostly inaudible to humans
b) Produce chemicals
called pheromones
9. Life histories
a) Most insects
hatch from eggs outside of the mother`s body
b) Young insects
undergo regular ecdysis, stages called instars
c) Simple metamorphosis
(1)
Wings develop during juvenile stages
(2)
Immature stages generally called nymphs
d) Complete metamorphosis
(1)
Wings appear only during resting stage just prior to final molt
(2)
Resting stage called a pupa or chrysalis
(3)
Pupa does not normally move, except mosquitos
(4)
Juveniles and adults live in distinct habitats
(5)
Development is indirect, larvae are wormlike
(6)
Larva do not have compound eyes
(7)
Larvae may or may not have legs
(8)
Generally have chewing mouthparts
(9)
Pupa generally are usually inactive and do not feed
e) Juvenile hormone
controls ecdysis and molting via ecdysone
X. Deuterostomes
A. Embryological Feature Shared by Four Phyla
1. Echinodermata, Chordata and two
smaller groups
2. Four phyla share common ancestry
B. Characteristics
1. Blastopore becomes anus, mouth
develops at other end
2. Have radial cleavage
3. Daughter cells are identical for
a brief period of time
a) Produce whole
individual if separated
b) Individuals are
identical in genetic makeup
4. Whole groups of cells move during
embryonic development
a) Coelom produced
by evagination of archenteron
b) Archenteron becomes
gut cavity
XI. Phylum Echinodermata: The Echinoderms
A. General Ecology of Echinoderms
1. Ancient group of marine animals,
well-represented in fossil record
B. Name means "spiny skin"
1. Examples: sea stars, brittle stars,
sea urchins, sand dollars, sea cucumbers
C. Basic Features of Echinoderms
1. Have epidermis stretched over an
internal skeleton
a) Endoskeleton
composed of ossicles: movable or fixed calcium plates
b) Plates enclosed
within living tissue when first formed
(1)
Bear spines as indicated by phylum`s name
(2)
Have perforations through which tube feet extend
2. Have a five-part body plan
3. Adults have no head or brain
a) Nervous system
composed of circular nerve ring and its branches
b) Capable of complex
response patterns, but lack centralized functions
4. Possess a water vascular system
a) Five radial canals
extend from a ring canal around the esophagus
b) Radial canals
determine basic five-part symmetry
(1)
Water enters through madreporite, a sievelike plate
(2)
Flows to ring canal through the tubular stone canal
(3)
Radial canals extend out into hollow tube feet
(4)
Some echinoderms have suckers at end of tube feet, others do not
(5)
Each tube foot has a muscular fluid-filled ampulla at its base
5. Feeding strategies of echinoderms
a) Sea cucumbers:
tube feet around mouth are modified for feeding
b) Sea lilies:
tube feet arise from branched arms, filter food
c) Brittle stars:
tube feet pointed and specialized for feeding
6. Development of the coelom
a) Large coelom
interconnected with complicated system of tubes
b) Helps provide
for circulation and respiration
7. Respiration and waste removal occur
through skin gills
8. Digestive system is simple but
complete: mouth, gut and anus
9. Capable of extensive regeneration
a) Some animals
may drop parts when attacked
b) May reproduce
asexually by splitting into parts
10. Sexual reproduction and fertilization
is external
a) Sexes are separate,
but difficult to distinguish externally
b) Develop into
free-swimming, bilaterally symmetrical larvae
c) Significantly
different from annelid/mollusk trochophore larvae
d) Larvae possess
bands of cilia, used for locomotion
D. Diversity of Echinoderms
1. Class Crinoidea: the sea lilies
and feather stars
a) Mouth and anus
located on upper surface in an open disk
b) Simple excretory
and reproductive systems
c) Extensive water
vascular system
d) Large numbers
of highly branched arms located around central disk
e) Filter feeders,
food collected by mucus from tube feet on pinnules
f) Sea lilies are
attached to a substrate by a stalk
g) Feather stars
detach from stalks early in development, attach to substrate by claw-like
structures
h) Sexes separate,
external fertilization
i) Females may brood
young
j) Crinoids resemble
early fossil echinoderms
2. Class Asteroidea: the sea stars
a) Most familiar
echinoderms, the "starfish"
b) Active, important
marine predators
c) Arms prominent
and set off from the disk, generally five in number
d) Mouth located
in center of the lower surface
e) Often feed on
bivalve mollusks
f) Sexes separate,
external fertilization
g) Females may brood
young
3. Class Ophiuroidea: the brittle
stars
a) Slender arms
more sharply set off from central disk than sea stars
b) Move by active
movement of their arms along the substrate
c) Capture suspended
particles with tube feet, long spines or arms
d) Arms detach readily,
helping protect animals from predators
4. Class Echinoidea: the sea urchins
and sand dollars
a) Lack distinct
arms, but retain familiar five-part body plan
b) Five rows of
tube feet protrude through plates of the skeleton
c) Skeletons are
made up of fused calcareous plates
d) Walk along substrate
with tube feet or movement of spines
e) Feed on algae,
debris scraped off the surfaces by triangular teeth
f) Reproduction
similar to other echinoderms
g) Larvae have long
arms, unlike those of other classes
5. Class Holothuroidea: the sea cucumbers
a) Soft, sluglike
organisms with tough, leathery outer skin
b) Most lie on sides
at the bottom of the ocean
c) Mouth is located
on one end
(1)
Surrounded by tube feet modified into tentacles
(2)
Tentacles secrete mucus to trap food particles
d) Calcareous skeleton
reduced to widely separated, microscopic plates
e) Have highly branched
respiratory trees that originate from cloaca
(1)
Water brought into and out of cloaca by muscular contractions
(2)
Gas exchange occurs across the respiratory trees
f) Have tube feet
on body, may be restricted to five grooves
g) Move by tube
feet or wriggling of the entire body
h) Some forms are
hermaphroditic, unusual for echinoderms