animal diversity

Animal Diversity 


Classifications of organisms

  • Kingdom protista (algae, protozoans)

  • Kingdom plantae

  • Kingdom fungi

  • Kingdom animalia 


All animals: general features

  • Obtain nutrients by ingestion

  • Diverse in form and habitat:

  • 99% are invertebrates

  • Most marine

  • Hox genes: determines location and when expressed for body parts during development(variation in animal body plans)

Evolution of animals 

 Colonial flagellate hypothesis- Evolved from colonial protists (choanoflagellate) 


9 Major groups

Porifera (sponges)

  • Group of specialized cells

  • Sedentary 

  • Choanocytes (choano- collar) (collar cells)

  • Importance of collar cells are filtering food from the environment 

Phylum Cnidaria

  • Corals, hydra, anemones, jellyfish 

  • Tentacles with stinging cells

  • Hydra:freshwater example 

  • Mobility 

  • Tissues 

  • Specialized stinging cells (cnidocytes) 

  • Relationship with clownfish 

  • Clownfish have insulation that secretes from its skin 

Flatworms: symmetry with distinct head/tai ends phylum platyhelminthes

  • Planarian- not harmful just part of food chain 

  • tapeworm

  • Distinct head and tail and flat bodies

Phylum Nematoda- round worms

  • Many estimated 500,000 species

  • Decomposers, soil health, food

  • Parasites on pets 

  • Hookworms- “vampire worms”

  • Heartworms- spread by mosquitoes (to occupy the circulatory system)

  • Round shape gives more room for organ development

Phylum mollusca

Three main groups:

  • Snails, slugs, abalone

  • Claims, oysters, mussels, scallops

  • Squid, octopus 

  • Calcium shell

Annelids: segmented worms

  • Earth worm

  • Leeches

  • Anticoagulant - doesn't allow blood to clot 

  • Anesthetic

  • Leeches in medicine- reattachment of digits (finger as ex) leeches attach to finger releases swelling and pressure  

Phylum arthropoda

  • Largest group, most widespread (⅔ of all species- over 1 million descriped)

  • Jointed appendages

  • Exoskeleton (chitlin) molting 

  • - protection

  • Anchor muscles

  • Adapted land

  • Well developed sensory organs 

Arthropod groups (75 % of all animals)

  • Arachnids- scorpions, spiders, ticks/mites

  • Insects(90% if the arthropods) - beetles, butterflies/moths, bees, dragonfly

  • Crustaceans- crab, amphipods/shrimp, gooseneck, barnacles, water flea, rollie pollies 

  • centipedes/millipedes

Phylum Echinodermata

  • Starfish, sand dollar, sea urchin (ALLL marine)

  • Endoskeleton 

  • Water vascular system 

  • Spiny surface

  • Tube feet