Download Oceanography Chapter 15: Marine Animals

Oceanography Chapter 15: Marine Animals
Heterotrophic – cannot synthesize their own food
Eat autotrophs or lower level heterotrophs
True multicellular critters arose 700-900 MYA (Proterozoic Eon)
>about 2 BY after cyanobacteria put out enough free oxygen into the atmosphere
¾ O2 Revolution - 1% to 20 % in 1.5 BY
¾ O3 formed – allow for critters to leave the water 400 MYA
Early views of life
Burgess Shale of B.C. “It’s a Wonderful Life”
Ediacara Hills of Australia
Chengjiang beds of SW China
Phylum- group of critters that share similar architecture, level of complexity and
evolutionary history (phylon- tribe)
¾ 90% of all living animals are invertebrates
¾ 33 invertebrate phyla (show you 9)
Phylum Porifera (Pons = holes, ferre – to bear)-aka {Sponge Bob}
¾ nearly all of the 10,000 species are marine
¾ Size: bean to a small car ⇒ Have spicules made of spongin (CaCO3, Si02)
¾ Widespread
¾ Shapes
⇒ Branching, vase-like, encrusting
¾ Suspension Feeders – strain plankton (400 gallons)
¾ No digestive system, no circulation, respiratory or nervous systems
Phylum Cnidaria (old Coelenterata)
¾ 9000 species – jelly fish, sea anemones, corals
¾ cnidoblasts – stinging cells (Figure)
(knide – nettle, blastikos – blast upward)
¾ Also have migratory cells which move nutrients around
¾ Cells
1. Gastrodermis – digestion and reproduction
2. Epidermis – protection and capture of prey
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¾
¾
¾
Radial symmetry – body parts radiate from a central axis like spokes on a wheel
No exeretory or circulatory system
Primitive network of nerves
Two forms (of body)
1. Medusae – jelly fish
¾ Biggest – cyanea – 12 ft bell, 59′ tentacles
¾ Sea Wasp – 50 ft tentacles can kill you in 3 minutes (Chironix)
2. Polyp – many footed
¾ Fixed typically
¾ Corals, sea anemones
¾ Corals – solitary – 12 inches diameter
¾ Colonial – ant sized – Hermatypic
¾ Zooxanthellac- dinoflagellates – symbiotic
¾ Prefer clear water
¾ Higher salinity – therefore, freshwater is deadly
Worm Phyla
¾ Transition to more advanced
¾ Bilateral symmetry – left side, right side
¾ Have head with sensory tissue
¾ Some flow through digestive systems and excretory systems
1. Simplest – Platyhelminthes – flat worms
Platys – flat
Helmins- worm
¾ Parasites – tapeworms of vertebrates
¾ Most are free- living scavengers and predators
¾ Few are greater than 1 ¼ inches in length
¾ Most primitive with a central nervous system with brain and light sensitive eye spot
¾ Larger flatworms lack a true respiratory an excretory system
¾ Eliminate wastes by diffusion through cells
(therefore, their body can be no more than a few cells thick)
2.
¾
¾
¾
Nematoda (Round worms) (nematos – thread)
Flow through digestive tract (mouth, butt)
Plentiful in almost all habitats
Most of the 12 k species are free living
Although some are parasitic (sushi)
¾ Plentiful
1 meter square by 4 cm thick=4,420,000 critters
3. Annelida Cannelus – ring
¾ Includes earthworm
¾ Advanced, segmented (Metamerism)
¾ Each segment can have its own nervous, muscular and repro tracts
Class Polychaetae (chaetae – bristles)
(Figure) – most important marine annelid
¾ 1-15 cm (1/2 to 6 inches)
¾ Feather duster- catches food
¾ Some are mobile, others in tubes
ADVANCED INVERTEBRATES
Phylum Mollusca (Molluscus – soft bodied) - Figure 15.10
¾ Contains 80k (second to Arthropoda)
¾ Clams, snails, octopus, squid
¾ Most are marine and have a shell –internal
-external
¾ Some species –acute eyesite, intelligence - octopus
¾ Probably came from a common ancestor of annelids
¾ Bilateral, heads, digestive tracts, nervous systems (a few are segmented)
¾ Structural diversity, can achieve great size
1. Gastropoda – Snails
¾ Abalone, conch, limpet, garden snail
¾ Grazers, suspension feeders, predators and a few are planktonic
¾ Beautiful shells – outside – shock absorber
inside- smooth
middle- CaC03 – strength
¾ Some do not have shells – Nudibranch (Figure)
2. Bivalvia – twin shells
¾ Clams, oysters, mussels
¾ Surrender mobility for protection, suspension feeders
3. Cephalopods (head foot- literal)
¾ Nautilus, Octopus,
Squid
⇓
⇓
⇓
external
none
small one
(shells)
¾ Squid and octopus more advanced
¾ Secrete an ink roughly their body size
¾ Squid – 59 feet long
¾ Squid – largest invertebrate
¾ Octopus- most intelligent – keen eyesight
¾ Only 450 species of cephalos now
Phylum Arthropoda
¾ Arthron (joint) poda – foot
¾ Lobsters, shrimps, crabs, krill, barnacles
¾ Million of species
¾ Most successful phyla
¾ Krill-greatest biomass
¾ Variation of annelid – per or pairs of legs (or appendage) per segment
¾ All are bilaterally symmetric
¾ Do not have good nervous system, intelligence or eyesight
¾ But do have 3 major advances
1. Exoskeleton – form fitting external covering
2. Striated Muscle – Quick, strong, lightweight form of muscle that makes
rapid movement and flight possible
3. Articulation – ability to bend appendages at specific points
¾ Exoskeleton – made of chitin (N rich carb)
¾ Molting – replacement of exoskeleton
¾ Largest class – insecta – all marines ones are water striders
¾ Crustacea – 30 k – primarily marine – gills
¾ Lobsters, crabs
¾ Bodies – 16 to 20 segments
¾ Big – King Crab – leg span of 12 feet
¾ Heaviest- lobster (48 lbs) feed 10 people
¾ Dominate oceans
Phylum Echinodermata
¾ Echinos (hedgehog, skim)
¾ Lack eyes, brains
¾ 6000 species
¾ Radial symmetry (Pentamerous)
¾ Five classes
1. Asteroidea – sea stars – water vascular system
2. Ophiuroidea – Brittle stars – leave an arm
3. Echinoidea – sea urchins, sand dollars
4. Holothuroidea –sea cucumbers
Figures 15.18-15.20 (15.18 - Sea Star, 15.19 – Water vascular, 15.20 – Brittle stars)
PHYLUM CHORDATA
¾ Posess notochord
¾ 40k species
¾ about 5% lose notochord – invertebrate chordates
1. Invertebrate chordates (Figure 15.22)
¾ Tunicates – sea squirts
¾ Suspension feeders – look like sponges
¾ Amphioxus (sharp at both ends)
¾ Invertebrate with some vertebrate features
2. Vertebrate chordates
a. Fish – possess gills, fins
¾ More than all other vertebrates combined
¾ Length – 0.4 inch to 60 feet
¾ Weight – 0.1g to 45 tons
¾ Speed – 75 mph (120 km/hr)
¾ Cold blooded – ectothermic
¾ 40% freshwater, 60% sea water
¾ 500 MYA first appeared, exploded 410 MYA
¾ Devonian Period (age of fish) – 408 –360 MYA
1. Class Agnatha – hagfish, lanpreys ↵ (Figure 15.25)
¾ Fewer than 50 species
¾ Slime to protect
¾ Lanpreys - parasitic
2. Class Chondrichthyes
¾ 280 MYA appeared
¾ sharks, slates, rays, chamaeras
¾ active
¾ cartilage skeleton
¾ sharks, rays – neg. buoyancy (no gas bladder) - (they’ll sink)
¾ diversity
¾ more people are killed by dogs each year than killed in the last century
by sharks
Sharks
¾ 80% of shark species are less than 2m long as adults
¾ Great White – 23 feet, 3000 lbs
¾ Mako- little one (13 feet) – attack small boats
¾ Largest – Whale Shark (60 feet, 90K pounds)
3. Class Osteichthyes
¾ 27K bony fish
¾ 90% are Teleostei (Perfect bone)
(cod, tuna, halibut, perch) – Figure 15.29
¾ 77 million tunas eaten
¾ Adaptations – camouflage, schools, speed, gas-filled swim bladders
The problems of Fishes
1. Viscosity, Shape and Propulsion
¾ Small ones – difficult
¾ Streamlined-tuna
(Figure 15.30)
¾ Eel like movement – not as efficient (Figure 15.31)
¾ Fastest 75 mph
2. Maintenance of level
¾ Cartilaginous Fish – swim constantly (no gas bladders)
¾ Gas bladders – swim bladders
¾ Fastest fish: no swim bladders
3. Gas Exchange
¾ Gill membrane take in dissolved 02
¾ Active fish – bigger – gill area
4. Osmotic Considerations
¾ Osmoregulators
¾ Freshwater would gain water
¾ Saltwater would lose water
5. Feeding and Defense
¾ Lateral line system – defects low frequencies
¾ Cryptic coloration (camouflage)
¾ Turbot (Fig 15.34)
¾ schools
¾ Flying Fish
Amphibians
¾ 2000 species exist – most are terrestrial
Marine Reptiles
¾ Turtles, sea snakes, marine lizards, marine crocs
¾ Salt glands- excrete salts from body fluids
Sea Turtles – 8 species of these
¾ Non retracting
¾ Figure 15.36 – Green one (Chelonia)
¾ Largest – Atlantic Leatherback (61/2 feet, 1300 lbs)
¾ Lay eggs on the beach they were hatched
¾ Ascension Island – studied there
Marine Crocs
¾ Mangrove swamps, reefs
¾ 23 feet, over a ton
Marine Birds
1. Tubenoses – Albatross (12 feet wing span, 22 lbs)
(rarely flap- aerodynamic wings)
2. Pelicans – throat poaches, webbed feet
¾ Light delicate
3. Gulls including Terns
4. Penguins – only southern hemisphere
MARINE MAMMALS
¾ Most advanced vertebrate group – 4300 species
All marine mammals possess:
1. Streamlined Body Shape – with limbs adapted for swimming
¾ Drag is reduced by hair or slippery skin
2. Generate internal body heat –high metabolic rate
¾ No marine mammals are smaller than a sea otter
(small ones would lose heat too fast)
3. Respiratory System is modified to collect and retain large quantities of 02
¾ Empty lungs completely more easily
¾ Could hold breath longer and utilize 02 – whales
4. Osmotic Adaptations – skin is impervious to water
¾ Take in little water
¾ Excrete salty pee
Three main Orders:
1. Cetacea – whales, dolphins, porpoise
¾ Thought to have evolved from hoofed land animals related to horse/sheep
¾ Range in size from 1.8m (6ft) to 33m (110 ft) weigh up to 110 tons
¾ Nostrils at top of head
Suborders of Cetacea (Fig 15.39)
1. Odontoceti – toothed whales
¾ Include Orca, Dolphin, Porpoise
¾ High brain weight to body weight ratio
¾ Largest – Sperm Whale – 60 feet - dives deep (3740 ft)
(can dive to 3740 feet)
¾ Search for food by echolocation (Fig 15.40)
¾ thought to use sound offensively as well
¾ Dolphins – 229 decibels
¾ Sperm Whales- 260 decibels
2. Mysticeti- baleen whales
¾ No teeth
¾ Eat krill (filter feed), and lots of it
¾ Feed close to the surface
¾ Blue Whale- largest – babies can grow at 9lbs per hour
¾ Social structure – Humpback, Bowhead
2. Order Carnivora
a. Suborder Pinnipedia – wing foot – seals, sea lions, walrus
¾ Leave ocean to mate and raise young
¾ Appeared to have evolved from the same stock as modern bears
1. Seals – covered with short coarse hair without soft under fur, no ear flaps
¾ Rear appendages for swimming- not useful on land
¾ Diving record – 5120 feet – elephant seal
2. Sea Lions – have hind limbs with a greater range of motion
(for use on land)
¾ Small ears, soft under fur
¾ Use front flippers for propulsion
3. Walruses – much larger
¾ 2 tons
¾ dig up clams with mouths
¾ use tusks for moving too
b. Suborder Fissipedia (Split foot)
(cats, dogs, coons, bears)
1. Sea Otters – smallest
¾ Densest and warmest fur
¾ Active & cute
2. Polar Bears – eat seals, beached whales
¾ Can swim 62 miles of open water
¾ 8ft tall, 1800 lbs
3. Order Sirenia
¾ Sirius -mermaid
¾ Dugongs and Manatees
¾ Herbivorous – (only ones)
¾ Graze on sea grasses, marine algae
¾ 10K world wide
¾ largest (15 feet, 1500 lbs)