Animal DiversityCHAPTER 32 & 33

What phylum?

What phylum?

What phylum?

Animalia

• Kingdom extends far beyond dogs, birds, and humans- vast array of diversity covers 1.3 million

animal species- definition is not straight forward because of

exceptions to every criterion4 defining characteristics

1. nutritional mode – heterotrophs2. Eukaryotic, multicellular3. Specialized cells – nerve and muscle4. Sexual Reproduction

Characterization by Body Plan

• Grade – group of animal species that share the same level of organizational complexity

• Body plan – set of morphological and developmental traits that define a grade

a. Symmetry- radial (from the center) bilateral – half mirrored

b. Tissues – germ layers – ectoderm, mesoderm, endoderm

c. Body cavities – coelom – fluid filled space separates digestive tract from outer body wall

Protostomes & Deuterostomes

Protostome vs. Deuterostome

• Cleavage – (P) Spiral (diagonal), determinate (early fate)

- (D)Radial (parallel or perpendicular), indeterminate (capacity to develop into complete

embryo)• Coelom Formation – (P) coelom forms from splits

in mesoderm(D) coelom forms from mesodermal

outpockets of digestive tube• Fate of Blastopore – (P) mouth forms from

blastopore (opening of digestive tube) (D) mouth forms from second

opening; anus forms from blastopore

Invertebrates

• Animals without backbones comprise 95% of world’s known animal species

• Occupy almost every kind of habitat from hydrothermal vents to frozen tundra

Phylum PoriferaSponges

- Sessile organisms usually to rocks or other surfaces

- Can live in shallow or deep- many different colors- usually asymmetrical- lack true tissues

• Collar cells (choanocytes) line inner surface- contain flagellum- create wavelike current to circulate

gallons of water each day- brings in food particles

• Amoebocytes- free moving cells - produce skeleton of spicules- digest and transfer nutrients

• Contain both male and female organs to cross fertilize to produce more offspring

Phylum CnidariaCnidarians

- include coral, jellyfish, sea anemones• Polyp (coral, anemones)

– Cylinder, mouth at top– Tentacles face up– Sessile

• Medusa (jellyfish)– Umbrella-shaped– Tentacles hang down– Free-swimming

• Stinging cells (Cnidocytes) contain tentacles that sting and grasp prey • Enzyme secreted• Digestion completed by cells

Platyhelminthes

• Flatworms – include planarians, tapeworms and flukes

- free living forms, most are parasitic- lack true body cavity- marine or

freshwater inhabitants

Rotifera

• Rotifers – smaller than most protists- multicellular, specialized organ systems- alimentary canal – digestive tube with

separate mouth and anus-parthenogenesis- reproduction that produces

females from unfertilized eggs*can produce males but only live long

enough to produce sperm and produce zygotes resistant to harsh conditions

Molluscs• Second largest phylum next to Arthropods• Soft body creatures• Some produce shells; made of CaCO3

Common Features

Visceral mass - contains all internal structures

Specialized foot – used in digging, grasping, or creepingMantle – covers soft body, enclosing internal organs, some produce shellsRadula – rasplike scrapers used in feedingClassesBivalviaGastropodaCephalopoda

Annelids

• Annelida meaning little rings; segmented worms

• Live in marine, freshwater, and damp soil

Three classesOligochaeta – earthwormsPolychaeta – marine wormsHirudinea - leeches

Nematodes• Nonsegmented worms or roundworms

- body encased in a tough coat called a cuticle- sheds as it grows

- alimentary canal- inhabit moist soil and decomposing matter in

lakes and oceans* important role in decomposition and nutrient

cycling- can be parasitic to plants and animals –

“animals that act like viruses”

Arthropods• Largest and most successful phylum

- mainly insects

Common features1. hard exoskeleton2. segmentation of body parts3. jointed appendages

- used to walk, feed, copulate, defense, and sensory reception

Arthropods

Subphylum and examplesa. Cheliceriforms – horseshoe crabs, spiders, scorpions, ticksb. Myriapoda – millipedes, centipedesc. Hexapoda – insectsd. Crustacea – crabs, lobsters, shrimp

Phylum EchinodermataCommon features• Echino- meaning spiny derm- skin• Radial symmetry from center of organisms• Endoskeletons of calcium carbonate-

spicules or spines• Water vascular system- complex series of

canals running throughout body with hydralic pressure causing water to enter and leave through tubes; aids in movement.

• Regeneration of body parts – sea stars

Phylum EchinodermaTypes of Echinoderms• Sea stars - Asteroidea• Sea urchins - Echinodea• Sea cucumbers -

Holothuroidea• Brittle stars - Ophiuroidea• Feather stars - Crinoidea