### animal:

Invertebrate
* All invertebrates have exoskeletons
  - share common traits
* Many invertebrates also eat fungi, both opportunistically and actively.
* Many invertebrates are also indicators of a healthy environment or one that is becoming polluted
  - considered garden pests
  - hermaphroditic, possessing both male and female sex organs
  - marine animals
  - microscopic
  - breed once for all, the act frequently marking the end of their life cycle
  - can tolerate lower oxygen levels than fish
  - feed on the fungal mycelia produced in animal nests
  - go through a process of metamorphosis at some phase in their life cycle
* Many invertebrates have a fluid-filled, hydrostatic skeleton, like the jelly fish or worm
  - well developed circulatory systems
* Many invertebrates have an exoskeleton
  - open circulatory system
  - little in the way of physical protection such as shells or exoskeletons
  - specialized sense organs, rather than ears, for hearing and equilibrium
  - move swiftly, but mostly in bodies of very small size
  - release ammonia across the whole body surface
  - rely on the river s current for supplying food or for respiration
  - reproduce asexually, including coral and starfish
  - reside in the root-like holdfasts which attach the plant to the rocky bottom
* Most invertebrates are organized in a way called symmetrical
  - osmoconformers, such that whales ingest seawater passively
* Most invertebrates can move
  - survive extreme natural events like severe storms, blizzards, and flooding
  - have open circulatory systems
  - move short distances compared to vertebrates
* Some invertebrates are carnivorous
  - build homes
* Some invertebrates can allow themselves to dehydrate without cellular harm
  - migrate for long distances
  - exhibit bilateral symmetry
* Some invertebrates have a soft body, while others have a hard outside covering
  - an internal skeleton
  - hemoglobin in solution in the plasma
  - more advanced sensory abilities involving antennae of one kind or another
  - live symbiotically with other organisms
* also have a pharynx
  - line the trackways, usually attributed to insects and crustaceans
* are all the other animals
  - animals that don t have a backbone
* are animals that lack a vertebral column , or backbone
  - segmented vertebral columns
  - who lack a backbone or spinal column
* are animals without a backbone
  - backbones like anemones, corals, shrimps, snails, and crabs
* are animals without backbones, and they are the largest group of animals
  - vertebrates are animals with backbones
* are animals without backbones, such as worms and insects
  - skeletal structures, such as insects, crabs, clams, and snails
  - any other animal that is classified outside of that class
  - classified as any species of animal without a backbone
  - cold blooded animals that rely on their surroundings to maintain their body heat
  - everywhere, influencing all other species, including humans
  - excellent environmental quality barometers
  - good sources of protein and energy for channel catfish
  - grouped into different phyla
* are important as parasites and are essential elements of all ecological communities
  - in the food webs of most water and land communities
  - impressive in abundance and diversity, living on land and in water and air
  - in alphabetical order by common name
  - indicators of water quality
  - just as nutritious as vertebrates
  - low in fat, high in protein, inexpensive, and, of course, easy to find
* are more polymorphic than vertebrates
  - susceptible to the effects of cadmium than are birds and mammals
  - noncontroversial, inexpensive and economical to maintain as experimental animals
  - responsible for pollinating many flowering plants
* are the animals without backbones and are the largest group of animals in the world
  - majority of the animal kingdom
* are the most common type of organism to reproduce asexually
  - diverse group of animals on our planet
  - numerous type of animals on planet earth
  - oldest known animals on earth
  - well represented in The Diversity of Life exhibit on the ground level
  - wild animals
* become common.
* can however have an external skeleton, for example crabs
  - provide evidence of the local environment and human activity
* considered include arthropods, coelenterates, helminths, and molluscs.
* constitute the majority of the animal kingdom.
* do much better in the swamp than vertebrates.
* exhibit a variety of defense mechanisms.
* feed on living and dead plant matter, and on each other
  - rapidly growing, salt-tolerant algae
* form a small proportion of the diet and include termites, grubs, and worms
  - their hard secretions into shells
* have a retinal light current, vertebrates a dark current
  - simple nervous system although they differ among species
  - chemoreceptors to detect food and perform other functions
  - complex life histories with both juvenile and adult stages
  - many different reproductive strategies
* have no backbone, so they instead have a shell like a lobster
  - vertebrae or backbone
* increase conduction velocity by increasing fiber diameter.
* is an animal
* lack a nervous system.
* make up by far the largest percentage of species that are yet unknown to science
  - much of the food larger aquatic organisms eat
  - the bulk of the animal kingdom
* occur in a tremendous variety of shapes and colors.
* often live in colonies.
* only have macrophages that roam around looking for and getting rid of foreign bodies.
* play a key role in the wetland food chain.
* predominate in breeding season, seeds are more important remainder of year.
* provide a concentrated source of protein and fat required by a rapidly growing animal
  - tasty food source, pollinate plants, and control pest species
  - variety of recreational activities
  - the protein and calcium necessary for egg production
* rapidly colonize restored wetlands and form the basis of much of the avian food chain.
* show a wide range of protective reactions to putatively painful stimuli.
* supply most of the protein needed for egg production.
* thrive in a variety of habitats worldwide.
* thus vary considerably with regard to body plans and life strategies.
* use complex combinations of smooth and striated muscle
  - myelin to increase action potential conduction velocity
* yield a plethora of atypical guanylyl cyclases.