Download Chapter 25 notes - Faulkner University

Faulkner University
Science Department
Principles of Biology (BIO 1402)
Chapter 25: Animals: the Invertebrates
Animals: megafauna,
multicellular heterotrophs
consumers: ingestion of nutrients from other organisms
sexaual and asexual reproduction
motility
development stages
embryonic cells
three possible layers : ecto, endo and mesoderm
Diversity in the Animal Kingdom
2M species with 50K vertebrate species
30 phyla total - 12 invertebrate phyla in text
widely diverse morphologies
body symmetry
radial
bilateral
cephalization/caudalization
gut type
saclike
complete – flow-through
body cavity type
coelumate
acoelumate
pseudocoelomate
segmentation
repeated units
specialized segments
fused units – body units
Sponges – Poriferans (8K species)
Aquatic: marine and fresh water
Central cavity body plan: bowl-shaped – radial symmetry
Not a gut
Collar cell lining
Pores
Spongin with spicules as a skeleton
Reproduction
Sexual sperms and eggs and swimming larval forms (Plankton)
Asexual reproduction: fragmentation and gemmules
Cnidarians: 11K species (coelenterates)
Aquatic: marine and fresh water
Tentacled
Mouth opening to saclike gut
Two body forms: radial symmetry
Medusa – jellyfish form
Polyp – anemone form
Specialized tissues
Nematocysts
Muscles
Nerve net
C hapter Notes
Outer and inner epithelium
Hydrostatic skeleton
Life cycles: alternation of generations
Reproductive polyps
Planula larvae
Colonial types
Ctenophores – comb jellies (few species)
Aquatic: marine and fresh water
Tentacled
Mouth opening to saclike gut
Modified radial symmetry
Three layered embryonic development
Flatworms: platyhelminthes (15K species)
Aquatic and fresh water
Cephalized and bilaterally symmetrical
Acoelomates
Saclike gut
Simple organ systems
Three kinds: Parasitic and free-living
Turbellarians: planaria
Trematodes: flukes – typically parasitic
Cestodes: tapeworms – parasitic with a scolex and proglottids
Reproduction
Hermaphrodism
Regeneration
Ribbon worms – Nemerteans (few species)
Similar to flat worms
Differences:
complete digestive system
circulatory system
separation of sexes
Round worms- Nematodes (20K species)– most abundant animal life form!
Like ribbon worms
False coelom
Notoriously parasitic but also free-living
Cuticle
Rotifers – 2 k species
Name comes from a pair of ciliated lobes on the head
Small - < 1mm with a “full” set of body organs
Fresh water
Cement glands and toes for temporary attachment and feeding as a sessile organism
Mollusks – 110 K species
Mantles and shell
Kinds
Gastropod – 90 K
Chitons – multi segemented dorsal plates
Bivalves – clams, scallops, oysters
Cephalopods – squid, octopi, cuttlefish
Parts: radula, gills, tentacles, ink sac, digestive system, brain, heart
Locomotion: slime, jet propulsion, clapping
Annelid – segmented worms – 15 K species
Leeches, polychaetes, earthworms
Setae – feet
Chaetae - bristles
Jaws, closed circulatory system, coelom
Arthropods – 1M species
Adaptations
Exoskeleton
Jointed appendages
Fused body segments
Respiratory structures
Efficient nervous system – sensory systems
Division of labor in colonies
Open circulatory system
Kinds
Arachnids – Spiders, scorpions, horseshoe crabs
Venom
Book lungs
Crustaceans – 35K species
Mostly Marine: crabs, lobsters, barnacles, pill bugs
Larval forms in plankton
Gills
Millipedes - 4 legs per body segment
Centipedes - 2 legs per body segment Insects – most arthropods
Insects – 1M+ species
Molting and growth
Nymphs – incomplete metamorphosis
Metamorphosis
Diversity: special feeding, fight, camouflage
Echinoderms – 13 K species in fossil record/ 6 K existent species
Endoskeleton
Tube feet and water-vascular system
Major digestive gland system
Spines
Strength!