chapter 7 - washington state universityrlee/ocean/chapt07clecture.pdfchapter 7 marine animals...

Chapter 7Chapter 7

Marine Animals Without a Marine Animals Without a

BackboneBackbone

Figure 32.8 Animal phylogeny based on sequencing of SSU-rRNA

InvertebratesInvertebrates•• ArthropodsArthropods

•• Characteristics of PhylumCharacteristics of Phylum::–– About 1 million species known, mostly marine About 1 million species known, mostly marine

–– Most marine species are in a group of arthropods called Most marine species are in a group of arthropods called crustaceanscrustaceans

–– About 75% of all animals on earth are arthropodsAbout 75% of all animals on earth are arthropods

–– Arthropods are very successful on landArthropods are very successful on land

–– Chitin exoskeletonChitin exoskeleton-- hard, but light and moderately flexiblehard, but light and moderately flexible

–– Since the skeleton is external, an arthropod must shed the shellSince the skeleton is external, an arthropod must shed the shellto be able to grow to be able to grow –– this process is called molting. There is a soft this process is called molting. There is a soft new shell underneath. new shell underneath.

InvertebratesInvertebrates

•• Types of Marine Arthropods:Types of Marine Arthropods:

•• CrustaceansCrustaceans–– 68,000 species68,000 species

–– 2 pairs antennae2 pairs antennae

–– Gills for respirationGills for respiration

–– Head and thorax fused into a single unit called a Head and thorax fused into a single unit called a cephalothorax; entire external body is called the cephalothorax; entire external body is called the carapacecarapace

–– Large array of appendages specialized for different Large array of appendages specialized for different functions; ex: pinchers on crabs, swimmerettes on the functions; ex: pinchers on crabs, swimmerettes on the underside of shrimp hold developing eggs, etc.underside of shrimp hold developing eggs, etc.

–– Types of crustaceans Types of crustaceans –– copepods, barnacles, copepods, barnacles, amphipods, isopods, crabs, shrimp, lobsters, etc.amphipods, isopods, crabs, shrimp, lobsters, etc.

Video of a copepod and an ostracod

http://www.youtube.com/watch?v=tkz_SJv5RLM

Ostracod

• Shrimp-like but inside a bivalve “shell”

Barnacles -Cirripedia

Isopods

• Look like pillbugs, normally small

• http://www.youtube.com/watch?v=xeOSXt

BCY30

Mantis shrimp - Stomatopods

• Second leg is a spear or club, special hard

chitin

• http://www.youtube.com/watch?v=pgvsQ6

oNZyo


•• Types of Marine ArthropodsTypes of Marine Arthropods

•• Sea Spiders:Sea Spiders:

–– Four of more pairs of jointed legsFour of more pairs of jointed legs

–– Not insects or true spidersNot insects or true spiders

–– pycnogonidspycnogonids


•• Types of Marine ArthropodsTypes of Marine Arthropods

•• Insects:Insects:

–– Very few marine insects existVery few marine insects exist

–– Many insects feed in the intertidal zone at low Many insects feed in the intertidal zone at low

tide, but these are just temporary visitorstide, but these are just temporary visitors

InvertebratesInvertebrates•• BryozoansBryozoans

•• Characteristics of Phylum:Characteristics of Phylum:

–– Small, colonial animalsSmall, colonial animals

–– Some are encrusting forms, others form a branching Some are encrusting forms, others form a branching

network that looks like a small treenetwork that looks like a small tree


•• BrachiopodsBrachiopods


–– Two shells or Two shells or ““valvesvalves”” enclose the bodyenclose the body

Figure 32.8 Animal phylogeny based on sequencing of SSU-rRNA


•• Arrow WormsArrow Worms

•• DeuterostomesDeuterostomes


–– 100 species, all marine100 species, all marine

–– These organisms are planktonic, but slightly These organisms are planktonic, but slightly larger than most planktonlarger than most plankton

–– They are voracious predators that are widely They are voracious predators that are widely distributed in the marine communitydistributed in the marine community

–– Grasping spines on head with venomGrasping spines on head with venom

–– They will swim in rapid, darting movements to They will swim in rapid, darting movements to capture preycapture prey


•• EchinodermsEchinoderms


•• Characteristics of Phylum:Characteristics of Phylum:–– Name means "Spiny Skin" Name means "Spiny Skin"

–– EndoskeletonEndoskeleton

–– Water vascular system with tube feet important in feeding and Water vascular system with tube feet important in feeding and locomotionlocomotion

–– Radial symmetry in adultsRadial symmetry in adults-- larvae are bilaterally symmetricallarvae are bilaterally symmetrical

–– Nervous system is decentralizedNervous system is decentralized-- no brainno brain-- this allows any this allows any portion of the body to leadportion of the body to lead

–– Can regenerate lost body partsCan regenerate lost body parts

–– All 7000 species exclusively marineAll 7000 species exclusively marine


•• Types of EchinodermsTypes of Echinoderms

•• Sea cucumbersSea cucumbers

•• Sea UrchinsSea Urchins

•• Sea StarsSea Stars

Invertebrate ChordatesInvertebrate Chordates

•• The Phylum Chordata is a phylum that The Phylum Chordata is a phylum that contains two invertebrate groups, contains two invertebrate groups, tunicates and lancelets, as well as many tunicates and lancelets, as well as many other, more familiar animals such as fish, other, more familiar animals such as fish, amphibians, reptiles, birds and mammals.amphibians, reptiles, birds and mammals.


•• Chordates have several features that are Chordates have several features that are seen at least during some portion of the seen at least during some portion of the life.life.


•• Tunicates Tunicates –– sea squirts, sea squirts, salpssalps


•• LanceletsLancelets


–– 23 species23 species

–– Very small, only up to 3 inches longVery small, only up to 3 inches long

–– Body shows segmented muscle tissueBody shows segmented muscle tissue

Choanoflagellate colonyBurgess shale fossils

• Many body plans are now extinct

• Only one chordate fossil found

chapter 7 - washington state universityrlee/ocean/chapt07clecture.pdfchapter 7 marine animals...

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