invertebrates

invertebrates

no backbone, most important, abundant, and diverse groups of animals on the planet
worldwide ocean distribution
97% of all described animal species are invertebrates
mostly benthonic, some pelagic

benthos

plants and animals that live on or in the bottom of the sea

infaunal

organisms that lives wholly or partially beneath the sediment

epifaunal

organisms living on (not in) the bottom

motile

move about on the bottom

sessile

stuck in a place (don't move)

porifera (sponges)

simplest and most primitive metazoan
sessile organisms, lack real tissues and organs
efficient filter feeders: feed on bacteria, detritus, coral mucus
can filter their entire volume in 4-20 minutes
classified broadly on their morphology, and also spicules (glass rods within tissue)
sexual and asexual reproduction
some species have economic importance
structure is based on microscopic interlocking spicules

morphology

large osculum - low pressure allowing water to flow through

cnidaria

diverse group containing over 9000 species
distinguishing feature are cnidocytes or neatocysts (stinging cells) which are used to capture prey
two body forms: medusa (free swimming) and polyp (benthic)
four classes: hydrozoa, schyphozoa, cubozoa, anthozoa

coral anatomy

polyps build a calcium carbonate cup a corallite to live in
coral
have stinging cells called nematocysts
classify species on corallite and external morphology

symbiosis

ecological relationship between different species that live in direct contact with each other

autotrophy

symbiotic relationship
coral provides protection for zooxanthellae and zooxanthellae provides food and color

coral sexual reproduction

mostly hermaphroditic
sexual maturity usually 7-10 years
spawning usually coordinated with lunar cycles

coral asexual reproduction

budding/fragmentation of existing corals
non dispersal methods

identifying corals

growth form
feature of coral surface
polyp size, density, distribution
polyp walls
polyp structure
tentacle structure
distinguishable features

branching (coral colony growth forms)

3D tubular corals that show evidence of secondary branching

encrusting (coral colony growth forms)

2D flat corals which encrust the substrata

sub-massive (coral colony growth forms)

3D tubular corals that stand erect but show no evidence of secondary brancing

tabulate/ plate (coral colony growth forms)

2D sheet like laying erect off, but horizontal to, the substratum

massive (coral colony growth forms

3D boulder like corals where growth is fairly uniform in all directions

mushrooms (coral colony growth forms)

solitary coral generally spherical, ovate, or elongate-ovate
prominent radial septa gives appearance of upside mushroom

foliose (coral colony growth forms)

2D sheet-like colonies generally growing in more than one direction and not laying horizontally

plathelminthes

flat worms
evolutionary transition from radial to bilateral symmetry
only one free-living class (turbellaria)

nemertea

have nervous and circulatory systems
unique proboscis apparatus: rhynchocoel
small

nemtoda

well developed nervous system
occurs in all environments, from hot springs to polar regions

annelida

segmented worms (earth worm, leeches)
four classes
worldwide distribution, from shallow to deep waters
most have parapodia (appendages that function as a limb)
have a proboscis
could be errant or sedentary
deposit feeders