Download - Animal Phyla
Phylum Porifera
•Sessile•Feed by filtering food particles from water that passes through pores in their body
•Sponges•Simplest animals•Lack true tissues and organs•Asymmetrical
Phylum Cnidaria•Jellyfish, Sea Anemone, Coral
•Tentacles with stinging cells
•Sessile or slow-moving
•Tentacles move food into the mouth, then into a digestive sac called the gastrovascular cavity
•Undigested food and wastes exit back through the mouth
•Radial symmetry
Phylum Platyhelminthes
•Flatworms•Mobile•Most are free-living carnivores
-Muscular tube projects through the mouth and sucks in food-Food is then transported to the gastrovascular cavity-Undigested food and wastes exit through the mouth
•But some are parasitic that absorb digested food from inside a host
-Flukes-Tapeworms
Phylum Nematoda•Roundworms
•Complete digestive tract has two openings. a mouth and an anus, at opposite ends of a continuous tube
•Decomposers, parasitic, or free-living
•Human parasitic examples: pinworm & hookworm
Phylum Annelida-segmented worms (earthworms, leeches)
-longitudinal and circular muscle fibers surrounding body wall
-closed circulatory system: blood remains contained within vessels
Phylum Mollusca
-snails, slugs, oysters, clams, octopuses, and squids
Phylum Mollusca AnatomyFoot – muscular mass of tissue that functions in locomotion (video clip)
Mantle – outgrowth of body surface that drapes over the animal – produces the shell in certain mollusks – functions in respiration, waste disposal, and sensory reception
Mollusks have an open circulatory system
– a heart pumps blood into vessels– the vessels open into chambers where the organs are bathed in blood
Phylum Echinodermata-sea urchins, sea stars, sea cucumbers
-spines and plates under the skin make up the endoskeleton (but with no central spine)
-the water vascular system is a network of water-filled canals that aid movement
-tube feet function in locomotion, feeding, and respiration
Phylum ArthropodaMost numerous and diverse animals
•75% of animals belong to this phylum•global population is 1 billion billion (1018)
1. crustaceans (lobsters, crabs, shrimp)2. arachnids (spiders, scorpions, mites, ticks)3. insects4. centipedes and millipedes
General Characteristics of Phylum Arthropoda
Segmented body (different segments):• head – sensory antennae, eyes, mouthparts• thorax – midsection that bears jointed
appendages• abdomen – houses digestive and reproductive
organs
General Characteristics of Phylum Arthropoda
-open circulatory system with a copper-based blood called hemolyph-unlike humans, arthropod blood does not carry oxygen
General Characteristics of Phylum ArthropodaHow do arthropods get oxygen to their tissues?
Aquatic arthropods have gills
Terrestrial arthropods have trachea – a system of air tubes
Exoskeleton – external skeleton that consists of proteins
mixed with chitin
– protection, avoid dehydration
Must molt periodically
General Characteristics of Phylum Arthropoda
CrustaceansHead and thorax is fused cephalothoraxHave antennae; mostly aquatic
Copepods play an enormous role in the food chain of marine and freshwater communities
ArachnidsHead and thorax is fused cephalothoraxNo antennae; mostly terrestrial
Two pairs of mouthparts:
1. Fanglike mouthparts used to paralyze prey with poison
2. Mouthparts used to manipulate prey once it is paralyzed
Insects – the most successful arthropods
Entomology – study of insects
Reasons for success:
-ability to fly-diverse feeding habits-ability to metamorphasize
Many arthropods, including insects, have compound eyes
Compound eyes consist of many eyes (can be over 1,000!)
Excellent in detecting motion, however, poor image resolution
MetamorphosisMetamorphosis – a process in which body form changes from the sexually immature to the sexually mature stage
Incomplete metamorphosis:
-change is not dramatic-molting causes insect to grow
Complete metamorphosis:
-larval stage function in eating and growing-adult stage functions in moving and reproducing
Phylum Chordata
Notochord – flexible rod that extends down the length of the body
Invertebrate chordates – notochord becomes skeletonVertebrate chordates – notochord disintegrates
Chordates are named after a structure that is found in all chordate embryos