Vertebrates and Evolution
This flexible rod in chordates provides skeletal support and forms part of human intervertebral discs.
What is the notochord?
Sharks use this organ full of oil to help with buoyancy.
What is the liver?
Fish use this bony flap to protect their gills and pump water over them.
What is the operculum?
These blood vessels always carry blood away from the heart.
What are arteries?
This part of the nervous system includes the brain and spinal cord.
What is the central nervous system?
These animals must continuously swim to avoid sinking and ensure gas exchange since they lack a swim bladder.
What are sharks?
Male sharks transfer sperm using these specialized pelvic structures.
What are claspers?
In fish, water flows one direction and blood the opposite, enabling efficient oxygen uptake via this mechanism.
What is countercurrent exchange?
Fish have this many heart chambers.
What is two?
This neuron structure receives incoming signals.
What are dendrites?
These fish possess rod-shaped bones surrounded by muscle and are ancestors of tetrapods.
What are lobe-finned fish (Sarcopterygii)?
This corkscrew-shaped structure increases surface area in the shark digestive tract.
What is the spiral valve?
Birds maintain very high metabolic rates due to this feature, which moves air through lungs in only one direction.
What is unidirectional airflow?
This circulation loop moves blood from the heart to the lungs and back.
What is pulmonary circulation?
This brain region handles sensory processing of sound and sight and coordinates orientation toward stimuli.
What is the midbrain?
This class of amphibians includes frogs and toads, known for strong hind legs and lacking tails as adults.
What is Anura?
Despite lacking these structures, sharks detect prey through electric fields and vibrations.
What are eardrums?
Amphibians supplement lung breathing through this method that requires moist skin.
What is cutaneous respiration?
This muscular structure prevents food from entering the trachea when swallowing.
What is the epiglottis?
This fast, nonspecific immune response includes inflammation and physical barriers.
What is innate immunity?
This type of egg contains four extraembryonic membranes, allowing animals to lay eggs on land.
What is an amniotic egg?
This term describes species whose young develop inside the uterus and are born live.
What is viviparous?
These small sacs at the ends of the respiratory tree allow rapid oxygen diffusion due to thin walls and large surface area.
What are alveoli?
In negative feedback, this type of response reduces or counteracts the original stimulus.
What is a dampening response?
These chemicals trigger fevers by resetting the body’s temperature set point.
What are pyrogens?