Chapter 32 Flashcards
Phylum Echinodermata
Sea stars, brittle stars, sea urchins, sand
dollars, sea cucumbers
A thin skin covers an endoskeleton of hard calcareous plates
Tube feet
Water vascular system
Echinodermata,
* A network of hydraulic canals for
* locomotion
* feeding
* gas exchange
* excretion
concept of keystone species
bigger impact on ecosystem than biomass implies
Phylum Echinoderm reproduction
Separate male & female individuals
* External fertilization & development – most species
* Internal brooding ~40% of Antarctic sea stars?
Anatomy of Phylum Chordata
notochord, post anal tail, pharyngeal slits, dorsal hollow nerve cord.
Pharyngeal slits or pouches
Openings to the outside of the body
region just behind the mouth
– Lets water that goes in the mouth to leave without going through gut in invertebrate chordates
– In vertebrates, used for gas exchange or other functions
Dorsal hollow nerve cord
Unique to chordates
develops into CNS
Notocord
A flexible rod located between nerve cord and gut
– Provides skeletal support for muscle attachment
– Only remnants of embryonic notochord found in most adult
vertebrates
Muscular post-anal tail
Skeletal elements (notochord) & muscles beyond the anus
* Lost during embryonic development in many species
* Non-chordates have a digestive tract that extends the length of
the body
subphylum Cephalochordata
lancelets
Chordate characteristics persist into adulthood
Suspension feeders
Subphylum Urochordata
Tunicates (sea squirts)
Filter feeders
Some colonial
– No notochord
– No post-anal tail
– No dorsal hollow nerve cord
all are found in the larval form
Subphylum Vertebrata
Vertebral column that encloses the nerve cord, replaces notochord
* Paired sense organs (eyes)
* Gills
* 3-part brain
* Endoskeletons that grows with the animal
* Closed circulatory system (high energy needs)
Hagfish
Jawless
* Lost vertebrae during evolution
– Ancestors had vertebrae
Lampreys
vertebrate, but no jaw
scavengers and predators (often ectoparasites)
Gnathostomes
jaws allow for grip & grind of food items
New evidence suggests that jaws evolved in
placoderm fish
* Derived from bone shields within skull
Chondrichthyes
sharks, rays, skates
Gnathostomes
* Cartilaginous skeleton
* Paired appendages
Tetrapoda
4 limbs, evolved from fins
Pelvis fused to vertebrae
No gill slits; pharyngeal clefts form inner ear structures
Amniotes
Shelled egg (post-fertilization)
Extra-embryonic membranes
Allows for development on land
Membranes
– Gas exchange
– Waste storage
– Nutrient transfer
Fluid protects embryo
Shell present in many species
characteristics of birds
Type of reptile
Egg shells are hard
Not leathery
Modifications for flight
Adaptions for flight
Reduced organ systems
Feathers
Modified scales
Keel on sternum
Hollow bones
endothermy
Ability to regulate temperature
– ”Warm blooded”
* Birds & Mammals
– Also some fish
* Requires more energy than
ectothermy
Mammals
Mammary glands
Internal incubation of young
Hair
Diaphragm to ventilate lungs
Specialized teeth
Advantages of internal incubation
Offspring develop at a
more consistent
temperature
2.Offspring are protected
3.Incubating offspring are
portable (mother is not
tied to nest)
Monotremes
Lay eggs
* No nipples
– Milk produced in glands
* Echidna & platypus
* Limited range
