Animals - Invertebrates

Learning Outcomes

Describe defining characteristics of animals.

Describe defining characteristics of each phylum.

Name/Recognize common examples of each phylum.

Explain the tube-within-a-tube body plan.

Describe differences between tissues, organs, and organ systems.

Explain trends in bilateral symmetry and cephalization.

Animals

multicellular heterotrophs (obtain energy and organic molecules by eating other organisms) do not have cell walls

Proifera -- the sponges

Proifera -- the sponges

no symmetry two cell layers, no tissues choanocytes

Cnidarians - anenomes and jellyfish

Cnidarians - anenomes and jellyfish

radial symmetry two tissue layers gastrovascular cavity (GVC) cnidocytes (stinging cells) hydrostatic skeleton nerve net

Platyhelminthes -- flatworms

some species are parasites

Platyhelminthes -- flatworms

bilateral symmetry three tissue layers organs cephalization

Tube within a tube body plan & tissues layers

https://youtu.be/Lgb4wMsZwZA

ectoderm

endoderm

mesoderm

Annelida - segmented worms

body composed of repeating segments

Annelida - segmented worms

bilateral symmetry three tissue layers organ systems cephalization metamerism -repeating body segments

Mollusca -- snails, clams, squid

mantle (pink)

mantle tissue that produces shell > 100,000 living species

Mollusca -- snails, clams, squid

bilateral symmetry three tissue layers organ systems cephalization mantle - forms/produces shell large muscular foot for locomotion

Nematoda -- roundworms

bilateral symmetry three tissue layers organ systems cephalization chitin containing cuticle longitunidal muscles only

Arthropoda - segments & jointed limbs

segmented body jointed appendages exoskeleton containing chitin

Arthropoda - segments & jointed limbs

Arthropoda - segments & jointed limbs

bilateral symmetry three tissue layers organ systems segmented body jointed appendages exoskeleton containing chitin

most species of any animal phylum 1 million known species of insects current estimates - 20 million insect species extant

Echinodermata -- seastars & relatives

water vascular system, exclusively marine

bilateral symmetry three tissue layers organ systems pentaradial symmetry in adults water vascular system and tube feet

Echinodermata -- seastars & relatives