Notes – Chapter 29
Invertebrates
Animals are
-multicellular, heterotrophic, eukaryotes
-most eat by ingestion
-store carbohydrates as glycogen
-have nervous and muscle tissue
-spend most of life in diploid stage, reproducing sexually
-zygote undergoes development – cleavage, blastula, and gastrulation, some animal life histories include larval stages
Animals inhabit
-all of biosphere, especially the seas – more diversity in marine than in fresh
-terrestrial difficult – basically only arthropods and vertebrates have adapted well
Most animal body plans developed in the Precambrian/Cambrian era
-Scientists rely on comparative anatomy and embryology
-Picture on pg. 590 – Need badly a colored transparency
-4 major evolutionary splits
-Parazoa – sponges – no true tissue
-Eumetazoa
-Radiata – Bilateria Split – any questions?
-Bilateria has left, right, dorsal, ventral, anterior, posterior and cephalization,
-Concentration of sensory parts at one end – gives the animal direction of movement
-Interesting point – use of the word “probably” in the sentence, pg. 590, column 2, last paragraph
-Echinodermata were always the exception – evolved radially from a bilateral ancestor
-Germ layers also a characteristic
-Ecto = outer covering and nervous system
-Endo = lining of digestive, respiratory, and associate outpockets of each – i.e.accessory organs – liver, lungs
-Meso = muscles and other organs between gut and outer covering
-Acoelomate-Coelomate
-Solid bodies – no cavity between gut and outer are acoelomates
-Flatworms,
-most are tube w/in a tube – Coelomates
-most have a blood system
-fluid cushions organs, helps organs to grow and move independently of body wall
-Protostome – Deuterstome split
-Proto – mollusks, annelids, arthropods,
-Deutero – echinos, chordates
-Proto cleavage – spiral, determinate
-Single cell could not survive on its own
-Deutero – radial, indeterminate
-Could survive independently, this is what makes identical twins possible, and possibly the cutting up of a starfish – regeneration
-difference in forming of the “mouth” end vs. the “anal” end
Phylum Porifera – Sponges
-sessile, lack true tissues (groups of cells performing a unified function)
-1 cm – 2 m height range
-9,000 species, 100 – fresh, the rest, marine
-no organization
-usually have central cavity
-filter feeders
-cells ingest by phagocytosis
-central cavity lined by amoebacytes – digest food, pass it on, make fibers made of calcium carbonate or silica or spongin (that’s the part of the sponge that persists when the actual animal is dead) Where is Mary Lou Wood when I need her? I want her glass sponge!!!!!!!! Maybe I’ll just order one!!!
-Hermaphrodites – both sexes in same organism
Phylum Cnidaria (the C is silent)
-Hydras, jellyfish, sea anemones, corals
-10,000 species, most marine
-have gastrovascular cavity – “gut”
-two life stages – alternations of generations, in some, actually
-polyp – asexual,
-sessile, adheres to substrate, hydras and sea anemones
- medusa – sexual
-flattened, free floating,
-jellyfish, for example
-Chrysoara quinquechirra – the sea nettle, the Chesapeake’s finest!
-Carnivorous, have cnidocytes – cells w/ stingers, harpoons – contain nemotocysts – stinging capsules
-97% water – hydrostatic skeleton
-nerve net, very simple nerve coordination, no brain
-Hydrozoa
-Hydra
-Scyphozoa
-Jellyfish, lives most of life as medusa
-Anthozoa
-Sea anemones (animal flowers) and corals
-Coral – build up calcium carbonate skeletons – reefs, Barbados, etc.
Phylum Ctenophora
-Comb jellies – 100 species, all marine
-Have comblike plates of fused cilia, largest animals to use cilia for locomotion
-Show movie, jellyfish
Phylum Platyhelminthes
-flatworms – 20,000 species
-flukes and tapeworms (parasitic) and planaria (Go Kate!)
-microscopic to 20 m long
-bilateral
-Class Turbellaria – Planaria (Show life on earth)
-Nonparasitic, carnivores, love meat
-Developed flame cells to get rid of nitrogenous waste, keep osmotic balance, allowed them to “move” into fresh water and wet, terrestrial habitats
-Head with eyespots for light and lateral flaps for smell
-Slightly more complex nervous system
-Actually can modify their response to stimuli, and…can learn right, left, and can learn by ingesting another planarian who has learned
-Can reproduce asexually by regeneration, or sexually – even though individuals are hermaphroditic, they cross fertilize
-Class Trematoda
-Flukes – parasites, other animals, full of reproductive organs
-Shistosomiasis – human parasite, - fresh water snail intermediate host, St. Lucia
-Class Cestoda – Tapeworms
-parasitic, humans, hooks on head, absorbs food already digested by host
-humans can ingest undercooked meat of pigs and cattle which contain larval stages
Phylum Nemertea – ribbon worms????????
-actually are the first with a complete digestive system – mouth and anus
Phylum Rotifer
-reproduce by parthenogenesis – females produce females from unfertilized eggs
-or produce degenerate males, can’t even feed themselves, only produce sperm
Phylum Nematoda – roundworms
-very numerous
-80,000 species
-1mm – 1 m
-sexual, usually sexes separate
-produce > 100,000 eggs/day – very resistant
-live in moist soil
-some attack plant roots, some human parasites (pinworms and hookworms, guinea worms, I think, trichina worms – pigs, liver, encyst in organs and muscles, like heartworm does in the heart of dogs, and then the filaria worm, lodges in the lymphatic system, causes major swelling called elephantiasis – wish I had pictures, tried on the Internet
Phylum Mollusca
-snails, slugs, oysters, clams, all “seashells”, octopus, squid
-50,000 species
-most marine, but there are some interesting fresh ones – zebra mussels
-Soft-bodied, most w/ shell of calcium carbonate, octopi and squid have internalized shell
-All have foot, visceral mass of organs, mantle which secretes shell
-Most are sexual, separate, but snails are hermaphroditic (think about it, harder to find each other on land – makes a certain very derogatory command seem sensible)
-Most have radula to scrape algae to eat, or to eat other mollusks, also siphons to suck water in, so filter feed too (take in all those terrible toxic dinoflagellates)
-Reproduction sexual but spawn into water
-Class Polyplacophora – Chitons
-Segmented shells – modern ancestor of ancient trilobites
-Class Gastropoda – one shelled, stomach foot
-Largest class, 40,000 species
-Snails, slugs, whelks etc. etc. etc.
-Torsion – rotation of visceral mass above the body
-Most shells conical, but limpets and abalone flattened
-First successful group to populate land
-lost gills, modified mantle to exchange oxygen in air
-Class Bivalvia – two halves of shells
-Clams, oysters, mussels, scallops
-These have siphons – suspension feeders – suck it in, gills filter, then blow out wastes
-Usually fairly sedentary
-Mussels secrete threads to hold
-Clams burrow in soft bottoms, oysters settle on hard bottoms
-Class Cephalopoda – Squid, octopi, and chambered nautilus
-Built speed, lots of sense organs, jaws,
-Only mollusks with a closed circulatory system (blood always contained in vessels)
-Well developed nervous system with complex brain, can learn, show bit of octopus video
Phylum Annelida – Segmented worms
-15,000 species
-1mm – 3 m (giant Australian earthworm)
-marine, fresh and terrestrial
-specialized regions of digestive tract (crop, gizzard, see birds)
-closed circ. System
-metanephridia, leads to pores on outside, to get rid of metabolic
-hermaphroditic but cross fertilize
-Class Oligochaeta – Earthworms
-Eats soil, wastes called castings – good for the soil
-Darwin estimated – 1 acre British farmland = 50,000 worms = 18 tons of casting per year
-Have setae on their sides to help them move
-Get oxygen through skin (why they surface during rain!!!)
-Class Polychaeta – “many” setae
-As well as bristles, have parapodia (feet like structures)
-Most are marine, big benthic population in tubes – called epifauna
-Picture, pg. 609 – neat colors
-Class Hirudinea
-The leeches – some parasitic, blood sucking
-Either slit skin, or dissolve using enzymes, along with an anesthetic
-Medical studies
-Find out what’s in enzymes and use it to bust clots
-Use leeches to restore blood flow to an area closed off by clots, such as when reattaching an appendage with little, tiny blood vessels
****This phylum important for segmentation and coelem
-coelem with fluid in it cause hydrostatic pressure, allows greater diversity in locomotion, also provides body space for storage, cushion for internal organs, a place for them to grow and develop, and…..separates body wall movement from organ movement
Phylum Arthropoda – most successful group of animals ever to live!! That’s heavy!
-1 billion individuals, 1 million species
-roughly 66% of all animals
-segmented, hard exoskeleton, and jointed legs
-allows for great diversity of specialization
-for instances, appendages used for walking, eating, sensing, copulation, defense
-exo made of protein and chitin (Ki’ tin)
-but, must molt to grow, making them temporarily vulnerable
-have lots of sensory – antennae, eyes, smell
-open circ. System
-coelem only in embryonic stages
-for respiration, have gills, trachea systems (insects) and book lungs
-most believe they evolved from annelids, or share a common ancestor
-Four main groups (subphyla, actually)
-Trilobites
-In fossils, became extinct
Spiders, ticks, scorpions, etc. – called Chelicerates
-have anterior appendages used for feeding
-Horseshoe crab - only surviving ancient species
-Lewes, Delaware beach – May – go there – there are billions who come in to mate – then most of them die and Lewes has to bury them – they stink, too!
-Use blood to do the ‘Quick” test for chlamydia
-Some fear that they will be overharvested for medical purposes so they’re putting down some laws about them
-Class Arachnida
- scorpions, spiders, ticks, mites
- 2 body parts, 8 legs
-as other arthropods, flies notably, these macerate food with chelicerae, then spit up digestive enzymes to dissolve, then they are absorbed
-these guys have book lungs, like pages of a book, big surface area for osmosis
-spin webs to catch prey, to wrap food, as droplines, unique design to species
-From Arachnids, came Insects (Uniramians)
-Millipedes, centipedes (mean, fast son of a guns), and all insects
-Pics of butterflies in Costa Rica
-Probably one of the earliest land animals
-Centipedes use poison claws
-Insects outnumber all forms of life
-26 orders – all habitats except marine
-have specialized mouthparts called mandibles
-evolution of flying greatly increased diversity
-3 body parts, 6 legs, one or two pairs of wings
-lots of wing adaptations – two separate (dragonfly), hooked together (flies), overlapping (butterflies) and posterior ones for flight and anterior ones for protective covering (beetles)
-Malpighian tubules for excretion, & trachea tubes for breathing – open at sides
-Complex nervous system, even with social behavior
-Honeybees, hives, sun dances
-Behavior is inherited
-See pictures on pgs. 616-617 for main orders
-Some undergo incomplete (juvenile look like small adults) and some, complete (egg, larva, pupa, adult)
-Lots of diversity in reproductive strategies – colors, odors, lights, sound
-Sexual with internal fertilization
-Many functions – pollinators, disease carriers, crop destroyers
-Cornell University’s Tom Eisner says, “Bug are not going to inherit the Earth. They own it now. So we might as well make peace with the landlord.”
- and Crustaceans
-40,000 species, mostly marine
-lobsters, crayfish, shrimp, barnacles, copepods (the most numerous single species on Earth), and roly-polys (only terrestrial crustacean), also isopods and amphipods, krill
-use calcium carbonate to harden their shell
Now, we switch to Deuterosomes……
Phylum Echinodermata – starfish, sea urchins, sand dollars, sea cucumbers
-sort of seems out of place here but they have the criteria – form a true co
elom, mouth and anus place in embryo
-radial symmetry
-hard, prickly outer covering
-water canals for locomotion, feeding and gas exchange
-separate sexes and they spawn (somewhat of a throwback, actually)
-7,000 species
-Class Asteroidea – starfish
-Very strong mouth for pulling apart shells, evert stomach
-Can regenerate lost arms
-Class Brittle Stars
-Class Sea Urchins and Sand dollars
-Black and white sea urchins – spines, remove from feet by lime juice and dripping candle wax on them – old Barbadian custom
-You can eat white sea urchin eggs – scramble them with chicken eggs, or by themselves. Frankly, they were a little too sandy for me
-Class Sea cucumbers
-Don’t look too radial but they were in the earlier stages, and still have 5 rows of tube feet
Phylum Chordata
- in 5-10 million years, all major forms of animals evolved (very quick in
in geologic time, called the Cambrian Explosion
-lots of debate among scientists as to the how’s and why’s
-about 35 different phyla
-some say it was caused by just a more immediate diversification by having to adapt to a variety of habitats or…..predator-prey, sort of forced very quick adaptation – eat or be eaten…….
Yeah!!!!!!!!!!!!!!!!!!!!
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