Chapter 39 Biology

Why is Homeostasis Important?

1) Enzyme function! ◦Temperature, pH, and other physical and chemical conditions have a dramatic effect on the structure and function of enzymes 2) Molecules, cells, tissues, organs, and organ systems function at an optimal level when homeostasis occurs.

List and describe the 4 methods of heat exchange?

1.Conduction: direct transfer of heat between two physical bodies that are in contact with each other 2.Convection: special case of conduction in which heat is exchanged between a solid and a liquid or gas rather than between two solids 3.Radiation: transfer of heat between two bodies not in direct physical contact 4.Evaporation: liquid water becomes a gas

Describe the three ways to increase surface area

1.​Flattening ◦Example: Fish gills have flattened, sheet-like structures called lamellae to increase oxygen uptake. 2.​Folding ◦Example: The mammal small intestine has folds called villi for increased nutrient exchange. 3.​Branching ◦Example: Small blood vessels called capillaries are highly branched to increase oxygen delivery to tissues.

Describe afferent and efferent signals in response to increases/decreases in temperature

A homeostatic system is based on three general components: ◦A sensor (afferent) ◦An integrator (control system) ◦An effector (efferent)

Describe what a tissue is

A tissue is a group of similar cells that work together as a unit to perform the same function.

Which of these choices is an example of a fitness trade-off? A.The evolution of large ears by African elephants allows for heat transfer to the external environment. B.Modifications of the ancestral vertebral column support upright human posture and also contribute to back pain. C.At high elevation, your body makes more oxygen-carrying hemoglobin and more hemoglobin-carrying red blood cells. D.Light-skinned humans vary in the ability to tan in response to sunlight.

A.The evolution of large ears by African elephants allows for heat transfer to the external environment. B.Modifications of the ancestral vertebral column support upright human posture and also contribute to back pain. C.At high elevation, your body makes more oxygen-carrying hemoglobin and more hemoglobin-carrying red blood cells. D.Light-skinned humans vary in the ability to tan in response to sunlight.

Which of the following is an example of an animal tissue type? A.cardiac tissue B.nervous tissue C.renal tissue D.lung tissue E.endocrine tissue

A.cardiac tissue B.nervous tissue C.renal tissue D.lung tissue E.endocrine tissue

What is Acclimatization?

Acclimatization: phenotypic change that occurs in an individual in response to environmental fluctuations ◦Short-term and reversible ◦Similar to acclimation, which refers to changes that occur in an organism in a laboratory

Describe animal adaptions

Adaptation results from evolution by natural selection ◦Elephants with alleles for larger ears have a better chance to survive and produce more offspring than elephants with alleles for smaller ears

What is an adaption?

Adaptation: genetic change in a population in response to natural selection exerted by the environment

African elephants have ears two to three times as large as those of Asian elephants. Which do you think lives in a cooler environment?

African

Tissues, Organs, and Systems :How Does Structure Correlate with Function?

An adaptive structure will have its size, shape, or composition correlate with its function ◦Example: Beak size and shape in medium ground finches from the Galápagos Islands correlates with diet

Describe energy density in mouse vs elephant

An elephant has more mass than a mouse, but a gram of elephant tissue consumes much less energy than a gram of mouse tissue does.

Describe multicellularity of animals

Animals are multicellular - their bodies contain distinct types of cells that are specialized for different functions.

Describe the two ways animals are studies

Animals are studied throughanatomy and physiology Example: elephant ears ◦Anatomy: An elephant's large ears are loaded with blood vessels. ◦Physiology: Elephants shunt blood to the surface of their ears where body heat can be transferred to the environment.

What do scientist who study animals study?

Biologists who study animal anatomy and physiology are studying adaptations

If a animal doesnt regulate it's internal temp, what does it do?

But some organisms conform to their external environment ◦Example: The body temperature of Antarctic rock cod closely matches that of the surrounding seawater.

Describe connective tissue in animals

Consists of cells loosely arranged in a liquid, jellylike, or solid matrix (determines the nature of the tissue)

What level does the relationship between structure and function begin at?

Correlations between form and function begin at the molecular level ◦Example: Protein shape correlates with their roles.

Describe epithelial tissue in animal

Covers the outside of the body, lines the surfaces of organs, and forms glands

Explain the 3 reasons why heat exchange is critical

Critical in animals ◦Overheating --> protein denaturation ◦High temps --> dehydration ◦Low temps --> hypothermia, slow energy production

Describe muscular tissue in animals

Functions in movement-related physiological activities

If energy wasn't lost as animals got larger, what would be the consequence?

If the metabolic rate did not decrease with increasing organism size, the surface area available for exchange of materials would fail to keep up with the metabolic demands of the organism.

Describe the surface area to volume ratio for diffusion in animal cells

In a cell, the surface area determines the rate that stuff diffuses into and out of the cell. In the same cell, the volume determines the rate at which the nutrients are used and waste is generated. This ratio affects the animal's overall physiology.

Where do most species lie with regard to keeping body temp constant and producing heat?

Japanese honeybees exhibit poikilothermy when defending their hives from predatory hornets. ◦They contract their flight muscles repeatedly to produce heat endothermically, and the rise in temperature kills the hornet.

Can animals regulate their internal temperature ?

Many organisms are able to regulate their internal conditions ◦Maintain relatively constant internal conditions even when the environment fluctuates ◦Example: A dog maintains a body temperature of about 38ºC whether it's cold or hot outside.

Describe metabolic rate vs basal metabolic rate (BMR)

Metabolic rate is the overall rate of energy consumption. The basal metabolic rate (BMR) is the rate at which an animal consumes oxygen while at rest with an empty stomach, under normal temperature and moisture conditions.

Describe nervous tissue in animals

Neurons + several types of supporting cells --> Transmits electrical signals by changes in permeability of the cell's plasma membrane to ions (action potentials)

Describe epithelial tissue

Provide protection and act as "gatekeepers" for the selective movement of water and nutrients across their inner and outer surface Polarity --> apical vs. basolateral side

Describe The Role of Regulation and Feedback

Regulatory systems --> constantly monitor internal conditions Each has a set point --> normal/target value

Describe relationship between structure and function at cellular level

Similar correlations between structure and function occur at the cellular level ◦Example: Cells that secrete digestive enzymes would contain a lot of rough ER and Golgi. Cell shape and function correlate ◦Example: Absorptive cells have a large surface area.

What is homeostasis?

Stability in chemical and physical conditions within an organism's cells, tissues, and organs The internal conditions remain relatively stable even though an organism's environment may change.

How Does Body Size Affect Animal Physiology?

The laws of physics apply! Body size has effects on how animals function: ◦Large animals need more food than smaller animals do, produce more waste, take longer to mature, reproduce more slowly, and tend to live longer. ◦Smaller animals lose heat and water more rapidly.

So what is the rule of thumb for BMR in animals in terms of magnitude?

The smaller the organism's mass, the higher its basal metabolic rate is likely to be. Inverse relationship

Describe fitness trade offs of animals

Trade-offs are inescapable compromises between traits

Which of the following is an example of connective tissue? A.cardiac muscle B.axons C.blood D.glial cells

Which of the following is an example of connective tissue? A.cardiac muscle B.axons C.blood D.glial cells

What is a gland?

group of cells that secrete specific molecules or solutions

Describe a negative feedback loop

hormones increase or decrease is controlled by the increase or decrease of its stimulating factor (like a thermostat) Homeostatic systems based on negative feedback Effectors reduce or oppose the direction of change in internal conditions

How do animals obtain heat? List and describe the 2 ways

◦An endotherm produces adequate heat to warm its own tissue. ◦An ectotherm relies on heat gained from the environment.

Describe how atoms are building blocks of molecules

◦Atoms make up molecules such as proteins ◦Molecules support the activity of cells ◦Cells with similar functions are organized into tissues ◦Tissues are organized into specialized structures called organs ◦Organs are part of larger units called organ systems, which consist of groups of tissues and organs that work together to perform one or more functions

What are the things you need to understand to begin this chapter?

◦Characteristics that make an animal an animal ◦Key innovations to body plan that occurred during the early radiation of animals? ◦Major lineages of animals ◦Modes of sensing, feeding, moving, and reproducing

Describe the fitness trade off of male crickets

◦Example 1: Male crickets have a trade-off between the size of a single spermatophore they create and the number of mating opportunities they can take advantage of.

Describe the fitness trade off of producing offspring

◦Example 2: It takes a lot of energy to produce offspring, but also a lot of energy to mount an immune response.

Describe heritable traits of animals

◦Heritable traits that make individuals more likely to survive and reproduce in a certain environment better than individuals that lack those traits

Is an animal's body temperature held constant? List and describe the two ways

◦Homeotherms keep their body temperature constant. ◦Poikilotherms allow their body temperature to change depending on environmental conditions.

Which one has a higher BMR: a mouse or an elephant?

◦If we look at the metabolic rate of the entire organism, the elephant is going to win - there is way more metabolizing tissue in an elephant than in a mouse. ◦If we look at per-mass metabolic rate, however, the situation flips. A gram of mouse tissue metabolizes more than 10 times faster than a gram of elephant tissue!