Animal Form & Function: Physiology, Evolution, and Homeostasis

What are the three essential functions all animals must perform?

Obtain nutrients and oxygen, fight off infection, and survive to produce offspring.

How does animal size and shape affect their interaction with the environment?

Size and shape influence how animals obtain resources and interact with their surroundings.

What is the role of the genome in animal body plans?

The genome programs the body plan, shaped by millions of years of evolution.

What is the difference between anatomy and physiology?

Anatomy refers to biological structure, while physiology refers to biological function.

What physical laws limit the range of animal forms?

Physical laws govern strength, diffusion, movement, and heat exchange.

What is convergent evolution?

Convergent evolution results in similar adaptations among diverse organisms facing the same environmental challenges.

What adaptations are necessary for larger animals?

Larger animals require thicker skeletons for support and more muscle mass for locomotion.

How does the exchange rate of materials relate to cell size?

The exchange rate is proportional to a cell's surface area, while the amount exchanged is proportional to its volume.

How do simple organisms achieve environmental exchange?

Simple organisms, like flat animals, have cells in direct contact with their environment.

What is interstitial fluid?

Interstitial fluid is the space between cells that links exchange surfaces to body cells.

What are the four main types of animal tissues?

Epithelial, connective, muscle, and nervous tissue.

What is the function of epithelial tissue?

Epithelial tissue covers the outside of the body and lines organs and cavities.

What are the types of connective tissue?

Loose connective tissue, fibrous connective tissue, bone, adipose tissue, blood, and cartilage.

What is the role of fibroblasts in connective tissue?

Fibroblasts secrete fiber proteins that are essential for the extracellular matrix.

What are the three types of muscle tissue?

Skeletal muscle (voluntary movement), smooth muscle (involuntary activities), and cardiac muscle (heart contraction).

What is the primary function of nervous tissue?

Nervous tissue is responsible for the receipt, processing, and transmission of information.

What are neurons?

Neurons are nerve cells that transmit nerve impulses.

What is the function of glial cells?

Glial cells support neurons and maintain homeostasis in the nervous system.

What two major systems coordinate responses to stimuli in animals?

The endocrine system and the nervous system.

What is the role of hormones in the endocrine system?

Hormones are signaling molecules that broadcast through the body and may remain in the bloodstream for minutes or hours, causing distinct effects at specific locations or throughout the body.

How do nerve impulses travel in the nervous system?

Nerve impulses travel to specific target cells along communication lines mainly consisting of axons, with transmission being very fast and lasting only a fraction of a second.

What is the primary difference between the endocrine and nervous systems?

The endocrine system is adapted for coordinating gradual changes affecting the entire body, while the nervous system directs immediate and rapid responses to the environment.

How do animals manage their internal environment in response to external fluctuations?

Animals manage their internal environment by either regulating or conforming to external changes.

What is the definition of a regulator in terms of internal control mechanisms?

A regulator uses internal control mechanisms to maintain internal stability despite external fluctuations.

What is homeostasis?

Homeostasis is the maintenance of a relatively constant internal environment, regardless of external conditions.

What are the key variables maintained in homeostasis?

Key variables include human body temperature, blood pH, and glucose concentration.

What is the role of negative feedback in homeostasis?

Negative feedback dampens a stimulus and moderates changes in the internal environment, playing a major role in homeostasis.

What is positive feedback and its role in biological processes?

Positive feedback amplifies a stimulus and helps drive processes, such as childbirth, to completion, but does not play a major role in homeostasis.

What governs physiological changes that occur cyclically every 24 hours?

Circadian rhythm governs these physiological changes.

What is acclimatization in animals?

Acclimatization is the physiological adjustment of an animal to changes in its external environment.

What is thermoregulation?

Thermoregulation is the process by which animals maintain an internal temperature within a normal range.

What distinguishes endothermic animals from ectothermic animals?

Endothermic animals generate heat through metabolism, while ectothermic animals gain heat from external sources.

What is the difference between poikilotherms and homeotherms?

Poikilotherms have body temperatures that vary with the environment, while homeotherms maintain a relatively constant body temperature.

What are the four physical processes through which organisms exchange heat?

The four processes are radiation, evaporation, convection, and conduction.

What is the major thermoregulatory adaptation in mammals and birds?

Insulation is the major thermoregulatory adaptation, reducing heat flow between an animal's body and the environment.

How do circulatory adaptations affect thermoregulation?

Regulating blood flow near the body surface can significantly affect thermoregulation, with vasodilation increasing heat loss and vasoconstriction decreasing it.

How does evaporative heat loss help in thermoregulation?

Evaporative heat loss, such as sweating or bathing, cools the body by promoting evaporation from the skin.

What behavioral responses do ectotherms and endotherms use to control body temperature?

They seek warm places when cold, orient themselves toward heat sources, bathe, or move to cooler areas to minimize heat absorption.

What is thermogenesis?

Thermogenesis is the adjustment of metabolic heat production to maintain body temperature, increased by muscle activity or hormonal stimulation.

What is nonshivering thermogenesis?

Nonshivering thermogenesis occurs when hormones increase mitochondrial metabolic activity to generate heat.

How do birds and mammals acclimatize to seasonal temperature changes?

They can adjust their insulation and change the lipid composition of their cell membranes.

What role does the hypothalamus play in thermoregulation?

It controls thermoregulation by triggering heat loss or heat-generating mechanisms.

What does fever indicate in terms of thermoregulation?

Fever reflects an increase in the normal range for the biological thermostat.

What is bioenergetics?

The overall flow and transformation of energy in an animal, determining its nutritional needs.

What are autotrophs and heterotrophs?

Autotrophs (like plants) harness light energy to build energy-rich molecules, while heterotrophs (like animals) harvest chemical energy from food.

How is metabolic rate defined?

The sum of all the energy an animal uses in a unit of time.

What factors can determine metabolic rate?

Heat loss, oxygen consumption, carbon dioxide production, and energy content of food consumed.

What is basal metabolic rate (BMR)?

The metabolic rate of an endotherm at rest, with an empty stomach, and not experiencing stress.

What factors influence metabolic rate?

Age, sex, size, activity, temperature, and nutrition.

How does body size relate to metabolic rate?

Smaller animals have higher metabolic rates per gram than larger animals.

What are the consequences of higher metabolic rates in smaller animals?

Higher oxygen delivery rate, breathing rate, heart rate, and greater relative blood volume.

What is the relationship between activity duration and maximum metabolic rate?

The maximum metabolic rate an animal can sustain is inversely related to the duration of the activity.

What is torpor?

A physiological state of decreased activity and metabolism that enables animals to save energy.

What is the difference between daily torpor and hibernation?

Daily torpor is short-term and adapted to feeding patterns, while hibernation is long-term and adapts to winter cold and food scarcity.

What is estivation?

A state that allows animals to survive long periods of high temperatures and scarce water.