Download General Biology II Animals • Porifera o No true tissues o

General Biology II
Animals
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Porifera
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No true tissues
o
Assymetrical
o
Larvae have motility
Eumetazoans
o
Radiata – diploblastic (2 embryonic tissue layers)
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Ctenophores
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Radial symmetry
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Structurally more complex than cnidarians (have complete gut) so phylogenetic
position is unclear
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Cnidarians
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Radial symmetry
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Life cycle: alternate between polyp and medusa stages, some species only exist as
one
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Planula larvae
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Hydrostatic skeleton
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Gastrovascular cavity
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Cnidocytes
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Nerve net
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Groups:
o
Anthozoa – sea anemones and corals
o
Hydrozoa – Hydra
o
Scyphozoa – “jellies”
Eumetazoans
o
Bilateria – triploblastic (3 embryonic tissue layers)
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Protostomes
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Platyhelminthes
o
Acoelomates
o
Gastrovascular cavity
o
Excretion – flame cells
o
Ganglion and nerve cords
o
Hermaphroditic
o
Some are parasitic
o
Groups:
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Turbellaria – free living flatworms
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Trematoda – flukes
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Cestoda – tapeworms
Lophotrochozoans (lophophore, trochophore larvae)
o
Mollusks
o
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Complete digestive cavity
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Mantle, shell, visceral mass
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Bivalves and gastropods have open circulatory system – hemocoel
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Cephalopods have closed circulatory system
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Groups:
o
o
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Gastropoda – snails, slugs
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Bivalvia – clams, oysters
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Cephalopoda – octopus, squid, nautilus
o
Different from other groups
o
Intelligent
o
Well-developed eye
Resemble flatworms but have complete gut
Annelids
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Complete digestive system
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Closed circulatory system
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Circular and longitudinal muscles
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Groups:
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Polychaetes – marine worms
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Clitellates – earthworms
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Hirudinea – leeches
Bryozoans
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Complete digestive system
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Only exclusively colonial animals
Brachiopods
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Polyplacophora - Chitons
Nemertea – ribbon worms
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o
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Look like bivalves but valves are dorsal and ventral
Ecdysozoans (molt, naupilus larvae)
o
Nematodes – round worms
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Complete digestive system
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Exchange gases through cuticle
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Have only longitudinal muscles
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Sexual dimorphism
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Important in genetic research – precisely 959 cells, only animal
whose complete developmental cellular anatomy is known
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o
Some are parasitic
Arthropods – largest group of animals
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Complete digestive system
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Exoskeleton
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Segmentation
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Jointed appendages
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Open circulatory system
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Segmented ganglia along ventral surface
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Respiration – crustaceans have gills, insects have trachea system
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Groups:
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Crustaceans
o
Shrimp, lobsters, copepods, krill, crabs, barnacles
o
Body plan – cephalothorax, abdomen (have appendages
on thorax and abdomen)
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Hexapods
o
Insects
o
Body plan – head, thorax, abdomen (6 legs on thorax,
none on abdomen)
o
Groups
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Cannot fold wings back against body –
mayflies, dragonflies (Odonata)
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Those that can fold wings against body and
undergo incomplete metamorphosis –
Orthoptera (grasshoppers, roaches, crickets)
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Those that cannot fold wings against body and
undergo complete metamorphosis –
Lepidoptera (butterflies and moths)
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Others – Lice and fleas (parasitic, lost ability
to fly)
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Myriapods
o
Body plan – head and trunk
o
Groups:
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Centipedes – 1 pair of legs per segment
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Millipedes – 2 pairs per segement
Chelicerates
o
Body plan – head and trunk
o
Modified mouth parts
o
Groups
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Merostomata – horseshoe crabs
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Arachnids – spiders, scorpions, mites, ticks
Deuterostomes
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Echinoderms
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Larvae are bilaterally symmetrical
o
Complete digestive system
o
Water vascular system
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Some are filter feeders, some use tube feet to help catch prey
o
Groups:
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Astroidea
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Ophiuroidea
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Sea stars
Brittle stars
Echinoidea
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Sea urchins, sand dollars
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Lack arms and covered with spines
Holothuroidea
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Sea cucumbers
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Lack arms
Crinoidea
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Sea lilies
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Hemichordates – acorn worms
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Chordates – notochord, dorsal hollow nerve cord, post-anal tail, ventral heart
o
Urochordates - tunicates
o
Cephalochordates – lancelets
o
Vertebrates
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Agnatha, Jawless Fishes
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Hagfishes
o
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Lampreys
o
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cartilaginous
Cartilaginous, many parasitic
Gnathostomes – “jaw mouths”
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Class Chondrichthyes– cartilaginous fishes
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Class Osteichthyes, Ray-finned fishes – bony fishes
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Coelacanths
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Thought to have gone extinct but were found
again in 1938
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Lungfishes – have lungs and gills
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Class Amphibia, Amphibians – tetrapod legs allowed movement
from water to land
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Amniotes – skin impermeable to water, kidneys excrete
concentrated urine, amniotic egg
o
Class Reptilia and Class Aves– includes birds and
squamates
o
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Class Mammalia
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Egg-laying mammals – platypus
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Marsupials – pouched mammals
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Placental mammals
Evolution of the primates
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Ancestral lineage split into prosimians (only few left today, include lemurs) and
anthropoids
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Anthropoids – monkeys, apes, humans
o
New World Monkeys – those that migrated to South America
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Arboreal, flat noses, long tails that grasp
Those that stayed in Africa gave rise to 2 lineages
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Old World Monkeys
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Hominoids – apes (chimp, gorilla, orangutan) and humans
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Australopithecines – small brained genus
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Homo genus – arose about 2mya
o
Homo habilis
o
Homo erectus
o
Homo floesiensis
o
Homo neanderthalensis – Neanderthals
o
Homo sapiens
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Only surviving species of genus today
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Cro-magons were early Homo sapiens that may
have out competed the neanderthals