Transcript 204_08Animals2

KINGDOM ANIMALIA
(Animals)
Campbell, Chapters 33 & 34
What are the
characteristics
and evolutionary
trends of the
following phyla
and classes?
-Nematoda: roundworms
-Arthropoda: arthropods.
-Arachnida: spiders, scorpions.
-Crustacea: crustaceans.
-Insecta: insects.
-Echinodermata: echinoderms.
-Asteroidea: sea stars.
-Holothuroidea: sea cucumbers.
-Echinoidea: sea urchins.
-Chordata: chordates.
-Urochordata: tunicates or sea squirts.
-Cephalochordata: lancelets.
-Vertebrata: vertebrates.
-Myxini: hagfishes.
-Cephalaspidomorphi: lampreys.
-Chondrichthyes: sharks and rays.
-Actinopterygii: ray-finned fishes.
-Amphibia: frogs, toads and salamanders.
-Mammalia: mammals.
-Testudines: turtles.
-Lepidosauria: lizards and snakes.
-Aves: birds.
Secrete external
skeletons, molt.
Phylum Nematoda “thread form”: round worms
>90,000 spp, in aquatic habitats, wet soils, inside plants and animals.
-Length: <1 mm to over 1 m.
-Cylindrical body, pseudocoelom.
-Complete digestive tract (tube with mouth and anus).
-Eat animals; algae and fungi; detritus; parasites of plants and animals.
-Longitudinal muscles, produce a thrashing motion.
-Ecdysozoa: molt a tough exoskeleton called cuticle.
Segmentation &
appendages: further
allowed division of
functions and a
great
diversification of
forms.
Cuticle: strength
and impermeability
solved desiccation
and structural
support > land.
Flight: allowed
insects to escape
predators, find food
and mates, and
disperse to new
habitats.
Phylum Arthropoda- “joint foot”: arthropods
-Over one million species, most of them insects. The most diverse,
widely distributed and abundant of all animal phyla.
-Length: 0.1 mm to 1.2 m.
-Segmentation, hard exosqueleton (external skeleton), jointed
appendages.
-Exoskeleton called cuticle, made of protein and chitin. Relatively
impermeable to water; strong, to protect and allow muscle attachment.
-Ecdysis (molt cuticle).
-Well-developed muscles and sensory organs for vision, taste, smell
and touch.
-Extensive cephalization (concentration of sensory equipment in
the anterior end of the body).
-Many species have compound eyes (composed of many
independent visual units).
Arachnida
-Mostly terrestrial.
-Cephalothorax (head and thorax as one region) with six pairs of
appendages: chelicerae (a pair of clawlike feeding appendages),
pedipalps (a pair of appendages usually functioning in sensing or
feeding) and four pairs of legs.
-Spiders are carnivores that use their chelicerae to inject poison into
and masticate (chew) their prey; they spill digestive juices and suck
up the liquid meal.
-Many spiders have the unique adaptation of catching flying insects
by stringing webs of silk, a protein produced as a liquid by special
abdominal glands.
-Scorpions are nocturnal carnivores, pedipalps modified as pincers for
defense and capture of food; the tip of the tail has a poisonous stinger.
-Ticks and mites are parasites in vertebrates and invertebrates.
-Mostly marine.
Crustacea
-Multiple appendages extensively specialized.
-The only arthropods with two pairs of antennae.
-Three or more pairs of appendages modified as mouthparts.
-Three or more pairs of legs.
-Filter-feeders, plankton eaters, carnivorous, detritus eaters, parasites,
scavengers.
-Crabs, lobsters, crayfish, shrimp, isopods, barnacles, copepods.
Phylum Echinodermata “spiny skin”: echinoderms
-About 7,000 species, all marine, in six classes. Length: 1 mm to 1 m.
-Pentamerous radial symmetry in adults: the body can be divided into
five parts arranged around a central axis.
-Endoskeleton (internal skeleton) of movable or fixed plates (ossicles)
and projecting elements (spines or tubercles).
-Unique water-vascular system, fluid-filled tubes beginning in the
madreporite and ending in blind-ending tube feet.
-Tube feet used for locomotion, food gathering, and gas exchange.
-Many have pedicellaria, thin, flexible stalks manipulated by muscles
and with three jaws apiece that offer protection.
Endoskeleton,
functionally similar
to arthropod
exoskeleton: a hard
shell encasing the
body, still limits
body size.
Asteroidea
Echinoidea
Holothuroidea
Phylum Chordata: chordates
-Length: <1 mm to 30 m.
-Segmentation, muscles arranged in segmented blocks.
-Jointed appendages.
-Most with a truly internal and jointed skeleton, differing from that
of echinoderms.
-Notochord. Longitudinal, flexible rod between digestive tube & nerve cord.
-Dorsal, hollow nerve cord. Vertebrates: becomes brain and spinal cord.
-Pharyngeal slits. Water exits w/o going through digestive tube. Filter feeding
invertebrate chordates; gas exchange, jaw support, hearing in vertebrates.
-Muscular, postanal tail. Provides much of the propulsive force.
Subphylum Urochordata
-Most sessile marine animals, some are colonial.
-Water enters through incurrent siphon, passes through pharyngeal slits
into atrium and exits through an excurrent siphon.
-Filter-feeders, trap food with a mucous net.
-Animal encased in a tunic made of celluloselike carbohydrate.
-Larvae presents all four chordate characteristics.
Subphylum Cephalochordata
-Small, burrowing animals that live along sea coasts.
-Adults possess all four chordate traits.
-Filter feeders, water exits through pharyngeal slits.
-Muscles serially arranged like rows of chevron (<<<<<<).
-Sensory tentacles around mouth.
Unique group of embryonic
cells that participate in the
development of various
structures.
(CRANIATES). Myxini
-All marine. Mostly bottom-dwelling scavengers.
-Slime glands along the sides to repel others and for protection.
-Cartilaginous skeleton.
-Mostly blind, well-developed sense of smell. Hagfishes.
Vertebral column,
encloses and protects
nerve cord; provides
support and makes
large body size and
fast movement
possible.
Cephalaspidomorphi
-Marine and freshwater environments.
-Clamp round mouth onto flank of live fish, use rasping tongue to
penetrate skin and ingest blood.
-Cartilaginous skeleton.
-No paired appendages, no jaws.
-Lampreys.
Jaws and
mineralized teeth,
allow to firmly grip
and slice food
items, and eat prey
that until then was
inaccessible.
Paired appendages
(fins), allow
accurate
maneuvering in the
aquatic
environment while
swimming.
Chondrichthyes
-Marine and freshwater environments.
-Cartilaginous skeleton, in most strengthened and with bony teeth.
-Skin covered by tooth-like scales. Sharks, rays, mantas, chimaeras.
-Rays: flattened bottom-dwellers that crush invertebrates with jaws, some
live in open water and filter food
-Sharks: streamlined
bodies and well-developed
jaws and fins.
-Most carnivores, some
filter-feeders.
-Sharp black and white
vision and well-developed
senses of smell and electric
fields in the head and of
water pressure along the
flanks (lateral line system).
Lungs or lung
derivatives, in
most fishes
developed into
swim bladder to
control buoyancy
and maintain
constant depth
without moving;
in other
organisms
allowed
obtaining oxygen
from the air and
thus exploiting
land
environments.
Actinopterygii
-Marine and freshwater environments.
-Ossified skeleton, skin often covered by flattened, bony scales.
-Skin glands secrete a mucus that reduces drag during swimming.
-Lateral line system and jaws; fins mainly supported by flexible rays.
-A protective flap called the operculum covers the gills.
-A variety of feeding mechanisms.
-Part of the “bony fishes”.
Legs, allow
better locomotion
in terrestrial and
very shallow
water
environments.
Amphibia
-Aquatic and terrestrial environments.
-Ossified skeleton.
-Moist skin, legs (secondarily lost in some species) and lungs (usually).
-Skin glands secrete distasteful or poisonous mucus as a protection
against predators.
-Mostly carnivores.
-Frogs, toads, salamanders, and newts.
-Still tied to water for reproduction, most abundant in damp habitats.
-Many go through a metamorphosis.
http://elib.cs.berkeley.edu/aw/
Amniotic egg
allowed terrestrial
vertebrates to
complete their life
cycle on land and
sever last ties with
aquatic past.
Milk, provide the
ability to
adequately
nourish offspring.
Mammalia
-Mostly terrestrial, some marine and freshwater.
-Skin covered with hair (reduced or absent in some species) and
mammary glands in the females to provide milk to the young.
-Legs lost in some.
-Amniote egg, but the embryo does not develop a shell.
-Variety of feeding mechanisms.
Testudines
-Terrestrial, marine and freshwater environments.
-Characterized by a hard shell, to which vertebrae and ribs are fused. Amniote egg with a shell.
-Sharp, horny beak without teeth.
-Most are carnivorous or eat plants or algae.
-Turtles, sea turtles, tortoises.
Lepidosauria
-Terrestrial, some in marine and freshwater environments.
-Legs lost in snakes. Amniote egg with a shell.
-Loose articulated jaws to swallow large prey, some inject poison.
-Most are carnivores with acute chemical (through the flicking
tongue), vibration and heat sensors.
Tuataras, lizards and snakes.
Feathers, provide
ability to fly and
insulation.
Aves
-Mostly terrestrial, some marine and freshwater.
-Skin covered with feathers, light and hollow skeleton; flight adaptations.
-Legs and wings, most species move by flying.
-Amniote egg with a shell.
-Mouth developed into a beak.
-A variety of feeding mechanisms.
SUMMARY
General traits of reviewed phyla, subphyla and classes.
Important evolutionary trends in body plan:
-Endoskeleton: Echinoderms.
-Notochord, nerve cord, tail, pharyngeal slits: Chordates.
-Cranium, brain development, neural crest cells: Hagfishes.
-Vertebral column: Vertebrates.
-Jaws, 2 sets of paired appendages, mineralized skeleton and teeth:
Sharks and rays.
-Lungs or lung-derivatives: “Bony fishes”
-Legs: Amphibians.
-Amniote egg: Mammals, turtles, snakes and lizards, birds.
-Milk: Mammals.
-Feathers: Birds.
These trends helped animals adapt to different environments or
exploit the same environment in a different manner.