Topic 24 Arthropods Flashcards
arthropods are the most _______ phylum of organisms
species-rich
Arthropod body plan consists of
a segmented body, jointed appendages, hard exoskeleton
Arthropod evolution is characterized by
decrease in the number of body segments, increase in appendage specialization, changes may have been caused in Hox gene sequences
all anthropoid ____ are segmented
embryos
body segments and limbs of anthropoids are arranged into
functional units with specialized functions
anthropoids have ____ _____ appendages
jointed paired
specialized functions of appendages
swimming, walking, feeding, sensory, reproduction, defense
Anthropoids have a sclerotized cuticle made of
chitin
exoskeleton
hard lightweight external skeleton formed by cuticle
the function of exoskeleton functions
provides support for muscle attachment
Cephalization
the concentration of nervous tissue in the head
Anthropoid reduced coelom
segmented limbs that are strong reduce the need for a hydrostatic skeleton
Anthropod primary internal cavity is called
hemocoel
How is the anthropoid circulatory system different
it is open - a circulatory fluid that circulates in spaces surrounding tissues and organs
Hemolymph
the circulatory fluid in the open circulatory system of arthropods
arthropods consist of three major lineages
Subphylum Chelicerata, Subphylum Myriapoda, Clade Pancrustaceans,
hexapods evolved within
crustaceans.
Clade Pancrustaceans includes
crustaceans and hexapods
Chelicerates are named for
claw like feeding appendages called chelicerae
two tagma of chelicerates
Anterior cephalothorax, Posterior abdomen.
Anterior cephalothorax
covered by a dorsal exoskeleton called carapace, with 6 pairs of appendages
Posterior abdoman has
no appendages, and contains the reproductive and digestive organs
chelicerae
modified appendages that appear before mouthparts
Spiders are ____ feeding predators
fluid (poison gland that empty through fangs)
Spiders have respiratory organs called
book lungs
Spinnerets
abdominal glands that produce silk
Scorpions
pedipalps modified as grasping pinchers, crush or sting prey to death
Mites
no seperation between cephalothorax and abdomen (like balls with legs), diverse oncology,
Myriapods
includes millipedes and centipedes, only terrestrial, body plan less stigmatized, gas exchange via trachael system, and have direct development (without larval stages)
Crustaceans
crabs, lobsters, shrimp, and relatives
Three clades of crustaceans
Isopods, copepods, decapods
Crustacean body plan includes
three tagma (head, thorax, and abdomen), exoskeleton covered in carapace, biramous limbs, two antennae, compound eyes
Small crustaceans exchange gas through ___ while larger crustaceans have ____
cuticle
gills
Hexapods
enormous clade including insects and relatives (6 legged)
Hexapod tagmatization (specialization of body aprts)
head with antenna and 3 pairs of mouthpars, thorax with 3 pairs of legs and wings, and abdomen without apendages
apterygota versus pterygota
apterygota have no wings while pterygota have wings
metamorphosis
indirect development from larval to adult forms
non-insect hexapods and apterygota insects transfer sperm _____
inderectly by spermatophore (enclosed package of sperm) on a substrate
Do pterygota insects copulate?
yes (sexual intercourse)
Insects shed entire exoskeleton cuticle during
molting - The new cuticle is produced before molting and is soft and wrinkled. After molting, the insect will swallow air or water to expand thenew exoskeleton.
