BIO 120 FINAL EXAM

What distinguishes proximate questions from ultimate questions in biology?

Proximate questions address immediate causation and development (How?), while ultimate questions focus on evolution and adaptive function (Why?).

List the levels of organization required for integration in physiological systems.

Atomic and molecular level, cellular level, tissue level, organ level, organ system level, organism level.

What role do feedback mechanisms play in physiology?

Feedback mechanisms drive physiology and maintain homeostasis, which is the balance and stability in chemical and physical conditions.

What is the difference between positive feedback and negative feedback?

Negative feedback opposes the stimulus that triggered the response, while positive feedback enhances or amplifies the stimulus, leading to a greater response.

What are the four postulates of natural selection proposed by Darwin?

1. There must be variation among individuals in a population. 2. Some variation must be heritable. 3. Survival and reproductive success are highly variable. 4. Survival and reproductive success are not random; individuals with certain heritable traits are more likely to survive and reproduce.

How does adaptation differ from acclimation?

Adaptation is an evolutionary process that occurs in populations, while acclimation is a reversible change in physiology in response to current conditions at the individual level.

Describe the process and outcome of fertilization in animals.

Fertilization occurs when an egg and sperm produce a zygote, which is diploid and contains maternal and paternal DNA along with other cellular components.

What are the three germ layers formed during gastrulation?

Ectoderm (outer), Mesoderm (middle), and Endoderm (inner).

What is the role of transcription factors in gene expression?

Transcription factors are proteins that bind to regulatory regions and control the initiation of transcription, allowing or preventing gene expression.

What is the significance of Pax6 in eye development?

Pax6 is an important transcription factor required for eye development, and its levels are regulated by factors such as the sonic hedgehog (Shh) protein.

How does metabolic rate vary between endotherms and ectotherms?

Endotherms (birds and mammals) have a relatively high metabolic rate and thermoregulate metabolically, while ectotherms have low metabolic rates and depend on environmental conditions for temperature regulation.

What is the main function of insulin in glucose homeostasis?

Insulin stimulates the uptake of glucose by cells, facilitating its use for energy and storage and helping to maintain glucose balance in the body.

What is diabetes mellitus and why is it a public health concern?

Diabetes mellitus is a disorder of glucose regulation, where individuals cannot properly manage blood glucose levels, leading to serious health complications.

Explain the concept of osmolarity.

Osmolarity is the concentration of solutes in a solution, measured in osmoles per liter, which affects the movement of water across semipermeable membranes.

What adaptations do freshwater fish have to maintain osmotic balance?

Freshwater fish are hyperosmotic regulators; they produce large amounts of dilute urine and actively uptake salts to combat water gain and salt loss.

What is the role of red blood cells in gas transport?

Red blood cells are responsible for carrying oxygen and carbon dioxide in the blood, facilitating efficient gas exchange during respiration.

What characterizes icefish, and how do they survive without red blood cells?

Icefish lack hemoglobin and red blood cells, surviving in cold, oxygen-rich waters where lower metabolic rates reduce their oxygen demand.

What is homeostasis?

Homeostasis is the maintenance of stable internal conditions in an organism despite changes in the external environment.

How do hormones contribute to physiological regulation?

Hormones are chemical messengers that regulate various physiological processes by binding to specific receptors and eliciting responses in target cells.

What is the role of the hypothalamus in homeostasis?

The hypothalamus acts as a control center that regulates physiological processes such as temperature, hunger, and thirst, maintaining homeostasis.

What are the primary functions of the respiratory system?

The respiratory system is responsible for gas exchange, supplying oxygen to the blood, and removing carbon dioxide from the body.

How is thermoregulation achieved in mammals?

Mammals achieve thermoregulation through behavioral adaptations and physiological processes such as sweating, shivering, and altering blood flow.

What is the cardiovascular system's role in homeostasis?

The cardiovascular system transports nutrients, gases, hormones, and waste products, helping maintain homeostasis by delivering essential substances to cells and removing waste.

What is apoptosis and why is it important?

Apoptosis is programmed cell death essential for development, maintenance of tissue homeostasis, and removal of damaged or diseased cells.

Describe the process of cellular respiration.

Cellular respiration is the process by which cells convert glucose and oxygen into energy (ATP), carbon dioxide, and water.

What is the significance of the blood-brain barrier?

The blood-brain barrier is a selective permeability barrier that protects the brain from harmful substances while allowing essential nutrients to pass.

What adaptations do desert animals have for water conservation?

Desert animals may have adaptations such as nocturnal behavior, efficient kidneys to concentrate urine, and the ability to tolerate dehydration.

What is the significance of variation in natural selection?

Variation among individuals in a population is essential for natural selection to occur, as it provides the raw material for evolutionary change.

Why is heritability important in natural selection?

Heritability is crucial because traits that confer survival advantages must be passed down to the next generation for evolution to take place.

How do survival and reproductive success contribute to natural selection?

Survival and reproductive success are key factors; those individuals that survive are more likely to pass their advantageous traits on to their offspring.

What does it mean that survival and reproductive success are not random?

It means that certain individuals possess heritable traits that increase their likelihood of surviving and reproducing, leading to differential reproductive success.

What is the relationship between variation and natural selection?

Variation among individuals is essential for natural selection to occur as it provides the necessary diversity for certain traits to be favored in survival and reproduction.

How does genetic drift differ from natural selection?

Genetic drift is a random process that can cause changes in allele frequencies in a population, while natural selection is a non-random process where survival and reproduction depend on advantageous traits.

What is the significance of adaptive traits in evolution?

Adaptive traits increase an organism's chances of survival and reproduction in a given environment, thus contributing to evolutionary change.

Explain the term 'fitness' in the context of natural selection.

Fitness refers to an organism's ability to survive and reproduce in its environment; higher fitness means better chances of passing on traits to the next generation.

What role do environmental factors play in natural selection?

Environmental factors determine which traits are advantageous, influencing which individuals are more likely to survive and reproduce.

What is osmosis?

Osmosis is the diffusion of water across a selectively permeable membrane, from an area of lower solute concentration to an area of higher solute concentration.

How does osmolarity affect cell behavior?

The osmolarity of a solution can determine whether a cell swells, shrinks, or remains unchanged; this occurs through the movement of water in response to osmotic gradients.

What is the difference between isotonic, hypotonic, and hypertonic solutions?

Isotonic solutions have equal osmolarity to the cell's interior, hypotonic solutions have a lower osmolarity (causing cells to swell), and hypertonic solutions have a higher osmolarity (causing cells to shrink).

What happens to red blood cells in a hypotonic solution?

In a hypotonic solution, red blood cells will swell and may burst (hemolysis) due to the influx of water.

What role do aquaporins play in osmosis?

Aquaporins are channel proteins that facilitate the rapid movement of water across cell membranes, enhancing the process of osmosis.

What is the difference between isotonic, hypotonic, and hypertonic solutions?

Isotonic solutions have equal osmolarity to the cell's interior, hypotonic solutions have a lower osmolarity (causing cells to swell), and hypertonic solutions have a higher osmolarity (causing cells to shrink).

What happens to red blood cells in a hypotonic solution?

In a hypotonic solution, red blood cells will swell and may burst (hemolysis) due to the influx of water.

What happens to red blood cells in a hypertonic solution?

In a hypertonic solution, red blood cells will shrink (crenation) due to the loss of water as it moves out of the cell.

What happens to red blood cells in an isotonic solution?

In an isotonic solution, red blood cells maintain their normal shape and size because the osmolarity of the solution is equal to that of the cell's interior, resulting in no net movement of water.

What is the process of protein synthesis?

Protein synthesis involves transcription of DNA to mRNA in the nucleus, followed by translation of mRNA to amino acids by ribosomes in the cytoplasm.