Lecture 5 Flashcards
how many known animal species are arthropoda?
-2/3
what are the key aspects of the arthropoda phylum?
-found in nearly all habitats
-segmented body covered by a cuticle (hard exoskeleton)
-have joint appendages
-bilaterians
-most undergo metamorphosis
-have stepwise growth
-open circulatory system
-have tagmata
what is the cuticle of an arthropod made up of?
-proteins
-chitin
what joint appendages do arthropods have?
-leg joints
-claws
-fangs
-antennas
what is the purpose of the leg joints in arthropods ?
-walking
what is the purpose of arthropods having claws?
-defense
-intimidation
-sensing + feeding
what is the purpose of arthropods having fangs?
-inject venom
what is the purpose of arthropods having antennas? what does this tell us?
-sensation (interpret surroundings)
-they have undergone cephalization
what does it mean to have an open circulatory system?
-hemolymph is circulated to organs + tissue spaces
-hemolymph leaves the heart and goes to arteries
-no veins to bring hemolymph back
what are tagmata?
-grouped segments
what 2 tagmata do arthropods have?
-cephalothorax (head + thorax)
-abdomen (many small segments)
what are the clades found within the arthropods?
-chelicerata clade
-myriapoda clade
-hexapoda clade
-pancrustacea clade
what 2 groups are within the chelicerata clade?
-eurypterids
-arachnids
what are examples of eurypterids?
-horseshoe crabs
-sea spiders
what are examples of arachnids?
-spiders
-scorpions
-ticks
-mites
what does the cephalothorax house in the arachnids?
-poision glands
what does the abdomen house in the arachnids?
-essentials organs
-heart
-reproductive structures
-digestive system
-silk glands
how many pairs of appendages do arachnids have?
-6 pairs
what is another name for fangs?
-chelicerae
what is another name for claws?
-pedipalps
how many pairs of legs do arachnids have?
-4 pairs
do arachnids have antennae? if not, why?
-NO
-they have sensitive eyes
what are the 2 groups within the myriapoda clade?
-centipedes
-millipedes
what are key features of the centipedes?
-1 pair of legs per segment
-carnivorous (eat other animals)
what are key features of the millipedes?
-2 pairs of legs per segment
-found in forest + tropical environments
-herbivorous (eats plants)
-gente
what is included in the hexapoda clade?
-very diverse (large) clade
-insects + other 6 legged organisms
what are key features of the hexapoda clade?
-in nearly every terrestrial habitat or in fresh water
-undergo one of the two types of metamorphosis
-lightweight chitinous exoskeleton
-3 tagmata
what are the two types of metamorphosis?
-complete metamorphosis
-incomplete metamorphosis
what is complete metamorphosis?
-larva to adult form
-energetically expensive
what are common larva forms?
-maggot
-caterpillar
-grub
what are examples of animals within the hexapoda clade that go through complete metamorphosis?
-beetles
-flies
-moths
-wasps
-bees
what is incomplete metamorphosis?
-juvenile form resembles the adult form
-considered “true bugs”
what are examples of animals within the hexapoda clade that go through incomplete metamorphosis?
-leaf hoppers
-aphids
-grass hoppers
what are the 3 tagmata that a hexapoda animal has? how many segments for each?
-head (5 segments)
-thorax (3 segments)
-abdomen (up to 11 segments)
what is included within the pancrustea clade?
-crustaceans + insects
what are the 2 groups of crustaceans?
-1 more closely related to insects (sister taxa)
-1 more closely related to myriapods rather than other crustaceans
what type of group is crusteacae?
-paraphyletic group (expand over multiple groups)
what 2 tagmata are found within crustecea?
-cephalothorax
-abdomen/tail
in crustacea, what are features of the cephalothorax?
-several antennae pairs
-chelipeds (theoretical arms/front legs)
-walking legs (varying #’s)
in crustacea, what are features of the abdomen/tail?
-heavily muscled
-helps movement in environments
where did flight evolution first occur?
-hexapoda clade (arthropods)
what are wings extensions of? are they considered appendages?
-extensions of the exoskeleton
-not considered appendages
what happens to wings when moulting/shedding stops?
-wings harden
how do wings/flight provide evolutionary success?
-escape predators faster?
-find food easier
-move to new habitats quickly
how are insects defined?
-have 3 body parts
-6 legs
-4 wings
-2 antennae
