Animal Groups Flashcards
What are the 7 most common animal groups?
Sponges
Cnidarians
Mollusks
Lophophorates
Echinoderms
Chordates
Arthropods
What are sponges?
Most archaic form of animal
They consist of simple cells held together by an animal protein called collagen
Also have spiny pieces called Spicules
Hollow with a central cavity lined with cells that generate a current and trap food
What animals are grouped up to be Cnidarians?
Sea Anemones, Jellyfish, and all types of coral
What are Cnidarians?
The first to have true tissues
All have a sac like body with a jelly like fluid consisting mostly of water
What do Cnidarians have to catch prey?
Stinging cells on their tentacles, small barbed whip loaded with toxins that penetrate prey
What are the living portions of coral reefs?
Polyps, resemble small sea anemones that inhabit the cavities within the coral skeleton
What is so unique about corals compared to other cniderians?
Tend to be better preserved as fossils since they are the only cnidarian to have a skeleton made of calcite
What animals are grouped up to be Mollusks?
Shell-building animals, like Snails, Clams, Octopus, and Squid
What do all mollusks have?
A muscular foot as well as a fleshy mantle used for making a shell
What are the three major groups of Mollusks and what animals are in them?
1) Bivalves (two valves) : CLAMS, SCALLOPS, OYSTERS
2) Gastropods (stomach-foot) : SNAILS, SLUGS
3) Cephalopods (head-foot) : OCTOPUS, SQUID
What does the muscular foot in bivalves do? What about for Gastropods, Cephalopods too?
Muscular foot usage:
Bivalves - Shaped like a blade and is used for burrowing into sediment, can swell into an anchor
Gastropods - Used to glide, muscular foot is their stomach
Cephalopods - Been modified into grasping tentacles, foot extends from their head hence (head-foot)
What do squids and octopus have that no other mollusk has?
Have an internal shell/skeleton
What makes up squid and octopus shells/skeleton?
CARBOHYDRATE CHITIN
What did some ancient cephalopods have? (Hint: Like the modern shelled Nautilus)
Large spiral shell made out of calcite
What animals are grouped into Lophophorates?
Shell-building BRACHIOPODS and the colonial BRYOZOANS
What makes a lophophorate a lophophorate?
Based on the presence of a structure called a lophophore, a tentacle-covered feeding organ
What animals are grouped into Arthropods?
CRABS, LOBSTERS, SHRIMP, BARNACLES, SPIDERS, INSECTS, and TRILOBITES
What is the commonality between all Arthropods?
All have jointed legs and a segmented body
Exoskeleton made out of chitin, this is essential for movement (allows the attachment of muscles
What defines the type of arthropod a specimen is?
Their 1 of 4 basic body plans
More than 10 legs - Millipede
10 legs - Crustacean
8 legs - Arachnids
6 legs - Insect
What is unique about exoskeletons?
They DO NOT Grow once built, they must molt in order to make a new one when they outgrow it
What animal is an arthropod but was once originally mistaken as a mollusk?
What so unique about them?
Barnacles
ONLY ARTHROPOD TO MAKE A SHELL OUT OF THE MINERAL CALCITE
Has a strong biological glue that keeps them stuck
What are grouped into Echinoderms?
Starfish, Sea urchins, sea cucumbers, brittle stars, and crinoids
What is the commonalty between all echinoderms?
ALL HAVE A 5-FOLD SYMMETRY
What are the skeletons of Echinoderms called? What are they?
They are called “test”
Overlapping calcite plates connected by muscle
How do all echinoderms move? With the help of what?
They all have tube feet with suction cups that are used for movement
Can grab onto objects and prey
What are the similarities between starfish and sea urchins?
Sea urchins are really nothing more than a starfish bent backwards and fused together
Tube feet face outward instead of downward
What are the similarities between sea urchins and sea cucumbers?
Sea cucumbers are really just sea urchins that have been turned sideways and stretched out
SEA CUCUMBERS HAVE A HEAD AND TAIL
What are the similarities and differences between Crinoids and Brittle starfishes?
Both have similar lifestyles and delicate arms
CRINOIDS LIVE ON A STEM
BRITTLE STARS CAN FREELY MOVE AROUND
What animals are grouped of with chordates?
Majority of large animals
Tunicates, Fishes, Amphibians, Reptiles, Birds, Mammals
What is the commonality of all chordates?
ALL have a spinal cord, “backbone”, gill slits, and a bony or cartilaginous tail
Have been modified in other chordates
