Download Porifera

Kingdom Animalia
Chapter 32 - 34
What you need to know!
• The characteristics of animals.
• The stages of animal development
• How to sort the animal phyla based on symmetry,
development of a body cavity, and the fate of the
blastopore
• The traits used to divide animals into groups
• Examples and unique traits for each phylum
discussed.
• The evolution of systems for gas exchange,
respiration, excretion, circulation, and nervous
control
• The 4 chordate characteristics
• Traits which distinguish each of the following groups:
Chondrichthyes, Osteichthyes, Amphibia, Reptilia,
Birds, and Mammalia
• Adaptations that allowed animals to move onto land.
• How the three classes of mammals differ in their
reproduction
Phyla
1.
2.
3.
4.
5.
6.
7.
8.
9.
Porifera
Cnidaria
Platyhelmithes
Nematoda
Mollusca
Annelida
Arthropoda
Echinodermata
Chordata
Classification in Animalia
Metazoa: most inclusive clad; all animal
phyla; multicellular, heterotroph as
opposed to protozoa (first life)
Eumetazoa: true tissue animals; all phyla
except porifera (sponges)
Bilateria: symmetry; all phyla except
cnidaria and porifera
Deuterostomia: blastopore = anus;
only echinodermata, chordata
Porifera (“pore bearer”)
Porifera
• Simplest animal – no true specialized
tissues
• No gastrula during embryogenesis, no real
germlayers
• No muscle, nerve cells, digestive tract
• Association of different specialized cell
• Pores for water flow
• choanocytes (collar cells) flagellated cells that
create vortex to suck in water/food
• amoebocysts (food digestion, food distribution)
feeding through phagocytosis
• skeleton cells make spicules made from calcium
carbonate
Porifera
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•
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Sessile (attached to bottom)
Spongocoel (central cavity)
Osculum (large opening)
Sexual reproduction: sequential hermaphroditism
(produce both sperm and eggs at times in their lives)
• Asexual reproduction: budding
Cnidaria
• hydra, jellies, sea
anemones, corals
• Gastrulation makes
cnidarians diploblastic
• endo/ectoderm
• no mesoderm
• Endoderm forms
gastrovascular cavity
(GVC): sac with a central
digestive cavity – one
opening
• Polyps and medusa
• Also called “Radiata”:
Radial symmetry
Cnidaria
• Hydrostatic skeleton (fluid
held under pressure)
• Cnidocytes-cells used for
defense and prey capture on
tentacles
• Special cnidocytes are
Nematocysts: stinging
capsule that when triggered
release a harpoon-like stinger
Nematocyst
Platyhelminthes
• flatworms, flukes,
tapeworms
• Bilateral, Triploblastic
• GVC with only one
opening
• Acoelomates w/o body
cavity: solid interior
• Some cephalization:
eyespot and nerve cluster
anterior
• Predators, scavengers,
parasites with multiple
hosts
Tapeworm host cycle
Nematoda
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•
•
•
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•
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round, hook, heartworms
Bilateral, triploblastic
pseudocoelomate
Complete digestive track
Unsegmented
No circulatory system
Cuticle (tough
exoskeleton)
• Decomposition and
nutrient cycling
• freeliving or parasitic
• Trichinella spiralis (tiny
worm parasites)
Mollusca
• (mollus-soft) snails, slugs,
squid, octopus, clams,
oysters, chiton
• Bilateral, true coelomates:
• Digestive tract
• Segmentation
• Circulatory system w/
simple heart (open)
• Internal or external shell calcium carbonate
• Cephalopoda: developped
eyes, cephalization
Special molluscs
• All have: foot (movement), visceral
mass (internal organs); mantle (secretes
shell); radula (mouth scraping organ)
• Ciliated trochophore larvae
• Classes:
• Gastropoda: snails (stomach footed)
• Bivalves: mussels (two-shelled)
• Cephalopoda: octopusses (head footed)
Annelida
• segmented worms
earthworms, leeches,
marine worms
• Bilateral, coelomate
• Body segmentation
• Closed circulatory system!
• Metanephridia: excretory
tubes
• “Brainlike” cerebral ganglia
• Hermaphrodites, but crossfertilize
QuickTime™ and a
Cinepak decompressor
are needed to see this picture.
Arthropoda
• trilobites (extinct); crustaceans
(crabs, lobsters, shrimps);
spiders, scorpions, ticks
(arachnids); insects
(entomology)
• Bilateral, coelomates
• segmentation
• most successful of all phyla
• Extensive nervous system,
muscles
• open circulatory system with
hemolymph
• digestive tract
Special features - arthropoda
• hard exoskeleton (cuticle)
made from chitin (fungi!,
polysaccharide with some N)
• Growth through molting
• Metamorphosis: juvenile
looks very different than adult
• jointed appendages
• Ventral ladder shaped nerve
chord
Metamorphosis
Insect characteristics:
• Outnumber all other
forms of life combined
• Malpighian tubules:
outpocketings of the
digestive tract
(excretion)
• Tracheal system:
branched tubes that
infiltrate the body
(gas exchange)
• Complete
metamorphosis: larva,
pupa, adult
QuickTime™ and a
Cinepak decompressor
are needed to see this picture.
Echinodermata
• sea stars, sea urchins,
sand dollars, sea lilies,
sea cucumbers, sea
daisies
• Secondary radial
symmetry (fake) due to
bilateral larvae
• Only deuterostomes
other than chordates
• Spiny skin; sessile or
slow moving
Echinoderm facts
• Water vascular system by
hydraulic canals (tube feet)
• Simple Endoskeleton
• Some segmentation (disk,
feet…)
• Short digestive tract
• Some nervous system
Vertebrate
Evolution
Clip and Diversity
Phylum
chordata
Subphyla in Chordata
Subphylum: invertebrate chordate
• Urochordata and chephalochrodata: invertebrate
chordates
Subphylum: vertebrata
Class:
1. Agnatha –jawless fishes
2. Chondrichtys-cartilage fishes
3. Osteichtys
4. Amphibia
5. Reptilia
6. Aves
7. Mammalia
Invertebrate Chordates
• Urochordata (tunicates; sea squirt); mostly sessile & marine
and Cephalochordata (lancelets); marine, sand dwellers
• Importance: vertebrates closest relatives; in the fossil
record, appear 50 million years before first vertebrate
• Intestinal tract, no circulatory system, not vertebral column,
no gills
Subphylum: Vertebrata; Class Agnatha
• jawless fish lampreys,
hagfish
• Most primitive, living
vertebrates
• Cephalization in cranium
• closed circulatory system
• Lack paired appendages;
cartilaginous skeleton;
notochord throughout life;
rasping mouth, no jaw
• Predators preying on
fishes
Class: Cartilaginous Fishes
• sharks, skates, rays
• Cartilaginous fishes; well developed jaws and paired
fins; continual water flow over gills (gas exchange);
lateral line system (water pressure changes)
• Closed circulatory system, gills
• Life cycles:
• Oviparous- eggs hatch outside mother’s body, frogs, fishes
• Ovoviviparous- retain fertilized eggs; nourished by egg
yolk; young born live reptiles, birds
• Viviparous- young develop within uterus; nourished by
placenta, mammals
Class: Bony fishes
• all other fishes
• vertebral column
• calcified bone
most numerous
• vertebrate
Class: Amphibia
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•
salamanders, frogs, newts, toads
1st tetrapods on land
Frogs, toads, salamanders, caecilians
Metamorphosis; lack shelled egg; moist skin for gas
exchange
• No amniotic egg
Class: Reptilia
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Lizards, snakes, turtles, and crocodilians
Amniote (shelled) egg
Scales with protein keratin (waterproof);
Lungs
3 chambered heart; exothermic (dinosaurs
endothermic?)
Superclass Gnathostomata, V
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Class: Aves: Birds
Endothermic
Amniotic eggs
4 chambered heart
Flight adaptations: wings
(hollow-boned); feathers
(keratin); toothless; one ovary
• Evolved from reptiles (amniote
egg and leg scales)
• Archaeopteryx (stemmed from
an ancestor that gave rise to
birds)
Class: Mammalia
• Mammary glands; hair (keratin); endothermic; 4chambered heart; large brains; teeth differentiation
to accommodate herbivore, carnivore
• Evolved from reptilian before birds
• Monotremes (egg-laying): platypus; echidna
• Marsupials (pouch): opossums, kangaroos, koalas
• Eutherian (placenta): all other mammals-placental
mammals
Order: Primates
• Characteristics: hands & feet for
grasping; large brains, short jaws,
flat face; parental care and complex
social behaviors
• Suborder: Anthropoidea •monkeys,
apes, humans opposable thumb
• 45-50 million years ago
• Family: Hominid australopithecines
• genus: Homo
• Species: habilis, erectus, sapiens
• Subspecies: neanderthaliensis,
sapiens
Human evolution
• Misconceptions:
• 1- Chimp ancestor (2 divergent branches)
• 2- Step-wise series (coexistence of human species)
• 3- Trait unison vs. mosaic evolution (bipedalism,
upright, enlarged brain)
The first humans
• Ape-human split (5-7 mya)
• Australopithecus; “Lucy” (4.0
mya)
• Homo habilis; “Handy Man” (2.5
mya)
• Homo erectus; first to migrate
(1.8 mya)
• Homo sapiens neanderthaliensis
(200,000 ya)
• Homo sapiens sapiens (1.0
mya?)
• Several species side by side
• Origin Africa