Chapter 40 Flashcards
What challenges do all animals face?
- Obtain nutrients and oxygen
- Excrete wastes
- Reproduce
Why is there such diversity in animal form?
Natural selection
Natural selection
Individuals with adaptable heritable traits are more likely to survive and reproduce
Individuals with adaptable heritable traits are more likely to survive and reproduce
natural selection
What does natural selection result in a correlation of?
form (anatomy) to biological function (physiology) - form fits function
What affects the way animals interact with the environment?
Size and shape
Laws of physics govern what?
all aspects of body size and shape
- strength
- diffusion
- movement
- heat exchange
Fusiform body shape
tapered at both ends
Why do swimming animals have fusiform body shape?
To swim quickly
What do larger organisms require for support?
Thicker skeletons and more muscle
Larger body size –> more muscle –> …
limited mobility
What must animals exchange with their environment?
nutrients, waste products, and gases
Where does exchange occur?
across plasma membrane of each cell *each cell requires an aqueous environment
What is the rate of exchange proportional to?
membrane surface area
What has a direct effect on how the animal exchanges energy and materials with its surroundings?
Animal size and shape
What happens to surface area to volume ratio (SA:V) as animals get larger without changing shape?
SA:V decreases, resulting in less surface area to support chemical activity (metabolic needs/exchange)
How can organisms maximize surface area?
- flattening
- folding
- branching
- projections
How do simple body plans exchange with the environment?
- maximize exposure of cells to aqueous environment
- simple diffusion
- facilitated diffusion
How do complex body plans exchange with the environment?
increasing the number of cells decreases the other surface area to volume ratio
What would lower S:V mean?
materials can’t reach all parts of a cell quickly (can’t meet metabolic needs)
What do all cells of complex body plans need to be surrounded by?
interstitial fluid (fluid between cells)
How do complex organisms increase surface area for exchange
highly folded internal surfaces for exchanging materials
What do body fluids link in complex body plans?
exchange surfaces to cells
Exchange surface circulatory fluid … cells
interstitial fluid
Disadvantage of complex body plans?
more energy required for exchange
Benefits of complexity
specialized organ systems help maintain homeostasis in a variable external environment
Four types of tissues in animals
- Epithelial
- Connective
- Muscle
- Nervous
Epithelial Tissue form
sheets of tightly packed cells, apical and basal surface
Apical Surface
free surface exposed to fluid or air
Basal surface
attached to connective tissue
Epithelial tissue function
outside covering, lines organs and body cavities, secretion/absorption
outside covering
barrier against mechanical injury, microbes, fluid loss
Epithelium tissue shapes
- Cuboidal
- Columnar
- Squamous
Form of connective tissue
contains sparsely packed cells scattered throughout extracellular matrix (ECM)
What does the matrix consist of?
fibers in a liquid, jellylike, or solid foundation
Three types of fibers (all made of protein)
- Collagenous fibers
- Reticular fibers
- Elastic fibers
Collagenous fibers
provide strength and flexibility
Reticular fibers
join connective tissues together
Elastic fibers
stretch and snap back to original length
Form of muscle tissue
consists of contractile filaments made of the proteins actin and myosin
Nervous tissue form
made up of nerve cells (neurons) and glial cells (glia)
Nervous tissue functions
Receive, process, and trasmit information
What do tissues, organs, and organ systems work together to do?
coordinate and control response to stimuli (changing environment)
Homeostasis
the maintenance on internal balance
How do organisms maintain homeostasis?
- Negative feedback
2. Positive feedback
Set point
the temperature that an animal tries to maintain
Sensor
detects stimulus
Stimulus
A fluctuation inthe variable above or below the set point
Tolerance curve
shows conditions that an organism can survive in
Negative feedback
reduces or dampens the stimulus (most mechanism of homeostasis involve negative feedback)
Positive feedback
Amplifies the stimulus (few examples for homeostasis)
Alterations in homeostatic conditions
Puberty, menstrual cycle, circadian rhythm
Regulated change
acclimatization
Acclimatization
an organism adjusts to a change in its environment, allowing it to maintain homeostasis
Acclimatization is a _______ change during an individuals lifetime
temporary (not to be confused with adaptation/population level changes)
Poikilotherm
Body temp. varies with environment
Homeotherm
body temp. remains relatively constant despite environmental change
Ectothermic
heat is gained from external sources
endothermic
heat is gained from internal metabolism (organism generates own heat)
Example of ectothermic
non-avian reptiles, fishes, amphibians, most inverts.
Example of endothermic
mammals, birds, many insects, some fish and some non-avian reptiles
Torpor
the inactive state hummingbirds enter when their body temperature drops considerably
Advantages of endothermy
- can be active at night and during winter
2. can sustain high levels of aerobic activity
Disadvantages of endothermy
- need to eat a lot of high energy food to maintain metabolic rates
- energy to produce heat isn’t available for growth and reproduction
Advantages of ectothermy
- can survive with less intake of food than endotherms
Advantages of ectothermy
- can survive with less intake of food than endotherms
2. more energy for growth
Disadvantages of ectothermy
- muscle activity and digestion slow as environmental temp drops, causing body temp. to decrease as well
- can’t maintain extended period of activity
- restricted to warmer climates
Thermoregulation > heat loss =
heat gain
Radiation
emission of electromagnetic waves by all objects warmer than absolute zero
Evaporation
Removal of heat from the surface of a liquid that is losing some of its molecules as gas
Balancing heat loss and gain
- radiation
- evaporation
- convection
- conduction
Convection
transfer of heat by the movement of air or liquid past a surface
Conduction
direct transfer of thermal motion (heat) between molecules of objects in contact with each other
Five adaptations that help animals thermoregulate
- insulation
- circulatory adaptations
- cooling by evaporative heat loss
- behavioral responses
- adjusting metabolic heat production
Countercurrent heat exchange
transfer of heat between fluid flowing in opposite directions (reduces heat loss via convection)
Bioenergetics
the overall flow and transformation of energy in an animal
What does bioenergetics determine?
how much food an animal needs
What does bioenergetics relate to?
an animal’s size, activity, and environment
Metabolic rate
the sum of all the energy an animal uses per unit time
how can energy be measured?
joules (J) or calories (cal) and kilocalories (kcal)
What must animals maintain for basic functions?
a minimum metabolic rate
Basal Metabolic Rate (BMR)
metabolic rate of an endotherm at rest at a “comfortable” temperature
Standard Metabolic Rate (SMR)
Metabolic rate of an ectotherm at rest at a specific temperature
Both BMR and SMR assume animal is:
- nongrowing
- fasting
- not stressed
