BIO 242 STUDY GUIDE 2026 QUESTIONS AND ANSWERS
GRADED A+
✔✔Chelicerates (Arthropods) - ✔✔spiders, scorpions, ticks, mites.
chephalothorax and abdomen, no antennae
✔✔what are humans? - ✔✔deuterostomes
✔✔key deuterostome lineages (2) - ✔✔-echinoderms
-chordates
✔✔Echinoderms (deuterostomes) - ✔✔sea stars, sea lilies, brittle stars, sea urchins,
sea cucumber
✔✔echinoderm (deuterosomes) characteristics (3) - ✔✔-radial symmetry (don't have
head)
-endoskeleton of calcium carbonate that protects and supports body.
-water vascular system used for moving and gas exchange
✔✔3 lineages of chordates - ✔✔-cephalochordata
-urochordoes
-vertebrates
✔✔shared characteristics of chordates (4) - ✔✔-pharengeal slits: openings from the
throat to the outside that function for feeding/gas exchange
-dorsal hollow nerve cord: bundle of nerves running the length of the body
-notochord: supportive flexible rod in back of he embryo (ventral to the nerve cord)
-A tail containing muscles that extend past the anus.
✔✔how did the dorsal nerve cord, pharyngeal pouches and notochord evolve in
vertebrates? - ✔✔- Dorsal nerve cord became the spinal cord
- pharyngeal pouches became gills (in aquatic species only).
-Notochord became vetrebral column.
✔✔Key vertebrate characteristics (3) - ✔✔vertebrae, skull, complex brain.
✔✔vertebrate diversity - ✔✔most diverse lineages are ray finned fishes and tetrapods.
✔✔new trait that arose in fish - ✔✔jaws
paired appendages (fins)
bones
lungs (modified swim bladder in some lineages).
, ✔✔tetrapods: what are they and what 4 lineages do they include? - ✔✔vertebrates with
4 limbs (some lineages later lost their limbs).
-amphibians
-mammals
-reptiles
✔✔are we all descended from fish? - ✔✔most likely
✔✔limbs of vertebrates diversified to enable.... - ✔✔running, crawling, burrowing,
swimming and flying.
✔✔Amphibians were the first to do what? - ✔✔-first tetrapods to live on land
✔✔origin of amniotic egg - ✔✔mammilia and reptiles
✔✔key traits of mammals (4) - ✔✔-lactation: production of milk by the mammary glads
to feed offspring
-endotherms: gain most of body heat from internal metabolic processes
-fur
-placenta
✔✔what did mammals begin to diversify? - ✔✔during the time of the dinosaurs,
underwent adaptive radiation after dinos went extinct.
✔✔Reptiles are the origin of what? - ✔✔origin of scales and feathers (water tightlayer).
✔✔how do reptiles give birth and obtain heat? - ✔✔lay amniotic eggs (some birth live
young)
most are ectotherms (except birds).
✔✔are birds reptiles? - ✔✔yes birds are reptiles
✔✔key characteristics of birds that set them apart from other reptiles (2) - ✔✔-reduced
number of bones, bones are thin-walled and hollow so they are extermly light weight for
thier size.
-endotherms; can sustain energy year round.
✔✔homeostasis - ✔✔stability in the chical and physical conditions within an organisms
cells, tissues and organs
✔✔thermoregulation and how animals vary in this. - ✔✔the process by which animals
control their body temperature
animals vary in how they obtain heat and weather body temperature is held constant.
GRADED A+
✔✔Chelicerates (Arthropods) - ✔✔spiders, scorpions, ticks, mites.
chephalothorax and abdomen, no antennae
✔✔what are humans? - ✔✔deuterostomes
✔✔key deuterostome lineages (2) - ✔✔-echinoderms
-chordates
✔✔Echinoderms (deuterostomes) - ✔✔sea stars, sea lilies, brittle stars, sea urchins,
sea cucumber
✔✔echinoderm (deuterosomes) characteristics (3) - ✔✔-radial symmetry (don't have
head)
-endoskeleton of calcium carbonate that protects and supports body.
-water vascular system used for moving and gas exchange
✔✔3 lineages of chordates - ✔✔-cephalochordata
-urochordoes
-vertebrates
✔✔shared characteristics of chordates (4) - ✔✔-pharengeal slits: openings from the
throat to the outside that function for feeding/gas exchange
-dorsal hollow nerve cord: bundle of nerves running the length of the body
-notochord: supportive flexible rod in back of he embryo (ventral to the nerve cord)
-A tail containing muscles that extend past the anus.
✔✔how did the dorsal nerve cord, pharyngeal pouches and notochord evolve in
vertebrates? - ✔✔- Dorsal nerve cord became the spinal cord
- pharyngeal pouches became gills (in aquatic species only).
-Notochord became vetrebral column.
✔✔Key vertebrate characteristics (3) - ✔✔vertebrae, skull, complex brain.
✔✔vertebrate diversity - ✔✔most diverse lineages are ray finned fishes and tetrapods.
✔✔new trait that arose in fish - ✔✔jaws
paired appendages (fins)
bones
lungs (modified swim bladder in some lineages).
, ✔✔tetrapods: what are they and what 4 lineages do they include? - ✔✔vertebrates with
4 limbs (some lineages later lost their limbs).
-amphibians
-mammals
-reptiles
✔✔are we all descended from fish? - ✔✔most likely
✔✔limbs of vertebrates diversified to enable.... - ✔✔running, crawling, burrowing,
swimming and flying.
✔✔Amphibians were the first to do what? - ✔✔-first tetrapods to live on land
✔✔origin of amniotic egg - ✔✔mammilia and reptiles
✔✔key traits of mammals (4) - ✔✔-lactation: production of milk by the mammary glads
to feed offspring
-endotherms: gain most of body heat from internal metabolic processes
-fur
-placenta
✔✔what did mammals begin to diversify? - ✔✔during the time of the dinosaurs,
underwent adaptive radiation after dinos went extinct.
✔✔Reptiles are the origin of what? - ✔✔origin of scales and feathers (water tightlayer).
✔✔how do reptiles give birth and obtain heat? - ✔✔lay amniotic eggs (some birth live
young)
most are ectotherms (except birds).
✔✔are birds reptiles? - ✔✔yes birds are reptiles
✔✔key characteristics of birds that set them apart from other reptiles (2) - ✔✔-reduced
number of bones, bones are thin-walled and hollow so they are extermly light weight for
thier size.
-endotherms; can sustain energy year round.
✔✔homeostasis - ✔✔stability in the chical and physical conditions within an organisms
cells, tissues and organs
✔✔thermoregulation and how animals vary in this. - ✔✔the process by which animals
control their body temperature
animals vary in how they obtain heat and weather body temperature is held constant.
