Digestive Design
Why do ruminants like cows have multi-chambered stomachs?
to allow microbial fermentation of cellulose-rich plant material for better nutrient extraction
What hormone signals hunger to the brain and where is it produced?
Ghrelin, produced in the stomach
Why do animals with high metabolic rates (like birds) need double circulation?
to efficiently deliver oxygenated blood under high pressure to tissues.
Why would a moth be attracted to a flame even though it's dangerous?
It may use light for navigation (positive phototaxis) and artificial lights confuse that system.
Two closely related amphibian species both rely on external fertilization. One lives in fast-moving streams, the other in still ponds. Predict which species produces more gametes and explain why.
The stream-dwelling species likely produces more gametes because fast water flow increases the chance that gametes will be washed away before fertilization, requiring a higher quantity to ensure success
what would happen if the pancreas failed to release bicarbonate into the small intestine?
acidic chyme would damage the intestinal lining and deactivate enzymes, impairing digestion.
why does insuline resistence cause blood glucose levels to remain high?
because blody cells don't respond to insulin, so they don't take up glucose efficiently.
how do capillaries facilitate nutrient and gas exchange?
they have thin walls and a large surface area, allowing diffusion between blood and tissues.
How does fixed action patter differ from a learned behavior?
It's an innate, unchangeable sequence triggered by a stimulus
An aquatic species using external fertilization starts migrating to warmer waters during breeding season. How might the temperature change improve reproductive success?
Warmer temp can speed up the development of gametes and embryos, increase metabolic rates, and promote synchronized gamete release, all improving fertilization success and survival
why does emulsification by bile help digestion even though bile contains no enzymes?
it breaks large fat droplets into smaller ones, increasing surface area for lipase action.
the mouse would continue eating and gain weight, as leptin normally signals satiety.
what might happen if the valves in veins stopped working properly?
blood could pool due to backflow, causing varicose veins or reduced return to the heart.
Why do animals raised in isolation sometimes fail to show normal courtship or fear behaviors?
Because some behaviors rely on learning during critical periods.
Imagine a zygote in an animal with internal fertilization fails to implant in the uterus. Predict the outcome and its implications for development.
the embryo will not develop further, leading to failed pregnancy or early loss. Implantation is critical for nutrient exchange and continued development in species with internal gestation
how would digestion be affected if the villi and microvilli in the small intestine were flattened?
nutrient absorption would drastically decrease due to reduced surface area
after a meal, how do insulin and glucagon levels change?
insulin increases to store glucose; glucagon decreases
why does breathing rate increase during exercise?
to supply more oxygen for cellular respiration and remove excess CO2
A rat learns to press a lever to get food. what type of learning is this?
Operant conditioning (trial-and-error learning)
compare how the need for parental involvement differed in species using external vs. internal fertilization, and explain why based on the mode of fertilization.
species with external fertilization tend to produce many gametes with little parental care, relying on quantity for success. Internal fertilizers often produce fewer offspring but invest more in each through gestation and sometimes postnatal care, increasing survival odds.
why do birds like hawks and sparrows have very different digestive tract lengths?
because carnivores (hawks) digest protein easily, needing shorter guts, while herbivores (sparrows) require longer guts for plant breakdown.
compare the hormonal regulation of energy storage when fasting versus after a meal. use insulin, glucagon, and storage forms in your explanation.
after eating: insulin promotes glucose uptake and glycogen/fat storage. During fasting: glucagon signals liver to break down glycogen and release glucose into the blood
Why is the left ventricle fore muscular than the right?
It pumps blood to the entire body, needing more force than the right ventricle, which pumps only to the lungs.
How can animal behavior shape natural selection?
This process, used by many single-celled organisms like bacteria, involves the organism splitting into two identical offspring, each with an exact copy of the parent's genetic material.
Fission!