Animal Evolution – Invertebrates Part II

ARTHROPODS meaning “jointed appendages” divided into 4 classes trilobites

Arthropods Chelicerates ticks

Arthropods Chelicerates (cont.) Spiders Scorpions Horseshoe crabs

ARTHROPODS Crustaceans crab shrimp crayfish

Arthropods Uniramians centipedes millipedes all insects grasshoppers

Arthropods Insects (cont.) bees moths flies

3 most important features of an Arthropod exoskeleton provides protection and is waterproof made of chitin insects flexible and leathery lobsters, crayfish extremely hard

Arthropods Jointed appendages used for movement and includes wings legs flippers claws antennae

Arthropods segmented bodies head brain thorax legs abdomen internal organs cephalothorax head and thorax fused spiders, crayfish and lobsters

Arthropods

Arthropods respiration gills (crustaceans) row of feathers located under the exoskeleton

Arthropods book gills (horseshoe crab) and book lungs (spider) layered like pages in a book increases the surface area for gas exchange

Arthropods tracheal tubes (terrestrial arthropods) spiracles bring air in through tracheal tubes network of tracheal tubes supplies oxygen to all body tissues by diffusion works well in small animals only internal transport well developed heart pumps blood through an open circulatory system

Arthropods blood is pumped from the heart through arteries once the blood reaches the tissues it is no longer kept in the artery the blood now bathes the tissues animal must move its muscles in order to move the blood blood now collects in spaces called sinuses the blood collects in a large cavity around the heart and is pumped back through the body

Arthropods excretion Anus solid wastes malpighian tubules dipose of nitrogen wastes becomes concentrated and is added to the undigested food green gland aquatic arthropods poisonous

Arthropods Nervous System well developed brain and ganglion highly sensitive picks up Reproduction sexual internal fertilization spiders and some crustaceans male deposits sperm packets that female

Arthropods Insect development

Arthropods Crab life cycle

Types of Insect Development Growth and molting Types of Insect Development egg young adult Incomplete metamorphosis Different stages exploit different resources at different times egg nymphs adult Complete metamorphosis egg larvae pupa adult

ECHINODERMS meaning “spiny skinned” examples starfish brittle stars sand dollars

Echinoderms sea urchins sea cucumber

Echinoderms sea lilies feather stars

Echinoderms Characteristics no posterior or anterior end primitive nervous system 2 sided oral surface mouth (ventral) aboral surface top (dorsal) internal skeleton larval stages closely related to that of chordates

Echinoderms

Echinoderms Water vascular system

Echinoderms Systems Water Vascular System madreporite Tube-like structure that opens to the outside connects to ring canal and hundreds of tube feet acts like a hydraulic pump creates a partial vacuum allows tube feet to grasp onto to objects/prey

Echinoderms digestive use tube feet to pry open prey clams, scallops flips stomach into shell secretes digestive enzymes when finished pulls stomach back into its mouth nocturnal

Echinoderms

Respiration use of thin walled tissue found tube feet skin gills

Echinoderms internal Transport (circulatory) distribution of nutrients is performed by digestive glands fluid within the body cavity excretion anus solid wastes tube feet and skin gills excrete ammonia wastes

nervous nerve ring that surround the mouth radial nerves

Echinoderms Reproduction Sexual separate sexes produce larvae with bilateral symmetry allow them to swim and feed settle on the ocean floor and mature into adults that have radial symmetry Asexual have the ability to regenerate as long as part of the ring canal is present