Exam 1 Flashcards
Three strategies of homeostasis
Conformers
Regulators
Avoiders
Four phenotypes levels that carry out homeostasis processes
Behavior
Physiology
Morphology
Biochemistry
What strategy of homeostasis do large animals typically exhibit and why?
Regulation, it is easier for them to hold onto heat
What strategy of homeostasis are animals with exoskeleton typically better at and why?
Regulation, the exoskeleton is impermeable
What strategies of homeostasis do plants typically exhibit and why
Conformity and avoidance
What are exaptations?
Non adaptive traits that become adaptive
What populations are more likely to undergo nonadaptive evolution and why?
small populations, they are victims of probability
What are four causes of nonadaptive evolution?
Stochastic environments, genetic drift, pleiotropy, and linkage disequilibrium
What are stochastic environments?
Environment subject to unpredictable changes due to probability
What is genetic drift?
random loss in allele frequency that reduces genetic variation
What is pleiotropy?
The ability of a gene to produce multiple phenotypes
What is linkage disequilibrium?
Certain alleles in different locations on chromosome are associated and inherited together
What is a reaction norm?
A spectrum of phenotypes induced by different environments
What are canalized traits?
intermediate traits that become fixed by stabilizing selection
What are polymorphic traits?
A trait with multiple favorable morphs
What is an allosteric effect?
When a ligand binds to an enzyme to inhibit or encourage function
What are activators in reference to the cell?
proteins that bind upstream to DNA promoter region to trigger gene expression
What are repressors in reference to the cell?
proteins that bind to the DNA operator and prevent gene expression
What are enhancers in reference to the cell?
proteins that increase the rate of gene expression
How does recombination cause evolution?
Typically an equal exchange of chromosomes parts but is sometimes unequal, thus altering genome
What are the four levels of cell physiology?
Membranes, epithelia, enzyme function, and cell signaling
How do unsaturated tails impact membranes?
increase fluidity
What are the three major parts of epithelia?
Apical cells, basal cells, and basement membrane
What do apical cells do?
Perform the function for the organ membrane they are apart of
What do basal cells do?
Line the epithelial tissue and hold it together
What does the basement membrane do?
Connect epithelial cells to underlying tissue
What are tight junctions?
An impermeable seal between cells with a fluid filled cavity between them
What are desmosomes?
Permeable joining of cells where cadherin strings attach their cytoskeletons
What are gap junctions?
Gap between cells with a transfer of molecule between them using connexons
What is Vmax?
The saturation point of an enzyme where all active sites are being used
What is Km?
A substrate’s affinity for an enzyme, the halfway point to Vmax
What is Kcat?
Catalytic effectiveness or how fast the enzyme burns through substrate
What does a low Km mean?
less substrate is needed to reach max velocity
What are isoenzymes?
Proteins with many variants in a single species
What are interspecific homologs?
Variants of a protein coded for by homologous genes
What are constitutive enzymes?
enzymes that are always present as baseline levels
What are inducible enzymes?
enzymes produced due to stress from environment
What are ligand-gated receptors?
double as a receptor and channel in membrane
What are G-protein coupled receptors?
extracellular signal triggers receptor to release second signal
What are intracellular receptors?
Receptors located in the cytoplasm or nucleus
What is polyphenism?
When developmental pathways are triggered by environmental factors
What are the 3 forms of essential nutrients?
Polysaccharides, proteins, and triglycerides
What is the targeting feeding strategy?
Adaptations are used for prey selection and capture
What is the suspension feeding strategy?
Significantly smaller organisms suspended in fluid are targeting for consumption
What do 3 things do bacteria in the Rumen do?
Digest structural proteins and fatty acid chains
Synthesize B vitamins and essential amino acids
Recycle nitrogenous waste
What are the four forms of physiological work?
Chemical energy
Electrical energy
Mechanical energy
Heat energy
What is the only step where energy is maintained in the body?
Biosynthesis
How does heart rate change with body size?
Smaller body size → faster heart rate
How does heart size change with body size?
Larger body size → larger heart
How does lung change with body size?
Larger body size → larger lungs
How does respiration rate change with body size?
Smaller body size → faster respiration rate
How does metabolic rate change with body size?
Decreases with body size, decreases slower as body sizes are larger
What are poikilotherms?
Organisms that source heat from the environment
What are endotherms?
organisms that source heat from themselves
What is temporal heterothermy?
Body temp changes relative to the time of year or day
What is spatial heterothermy?
Heat is generated in specific parts of the body
What does eurythermal mean?
Can withstand a broad range of temps
What does stenothermal mean?
Can withstand only a small temp range
How poikilotherms mostly thermoregulate?
behavioral mechanisms
How are acute thermal responses performed?
increasing metabolic rate with body temp changes
How is Q10 used to compare acute thermal responses?
Q10 is how many times the metabolic rate is increased based on a 10 degree temp difference
How are chronic thermal responses carried out?
Acclimation causes metabolic responses to compensate for environment
How are evolutionary thermal responses carried out?
Utilizing enzymes that can exist at certain temperatures and work well
What two strategies do poikilotherms employ to prevent freezing?
Supercooling and antifreeze compounds
What two strategies poikilotherms and other organisms tolerate freezing?
Concentrate solutes in cells to prevent freezing and allow interstitial fluid to freeze
Produce ice nucleating compounds in interstitial fluid so only it freezes
What are colligative antifreeze compounds?
reduces feezing point by concentration
What are non colligative antifreeze compounds?
reduces freezing point by disrupting ice crystal formation
What is the thermal neutral zone?
Range of ambient temps where homeotherm basal metabolic rate is constant
What is the lower-critical temperature?
Lowest ambient temperature of the thermal neutral zone
What is the upper-critical temperature?
Highest ambient temperature of the thermal neutral zone
What four strategies do homeotherms employ when they are under the lower-critical temperature?
Insulation, shivering thermogenesis, non shivering thermogenesis, and spatial heterothermy
What is nonshivering thermogenesis?
Brown fat is burned and the H+ protons produced are sent through uncoupled protein (thermogenine) which produces only heat
What is spatial heterothermy?
Appendages stay cool because they are more exposed so counter current exchange warms blood in the appendages before it returns to the heart?
What three strategies do heterotherms employ when they are above the upper-critical temperature?
evaporative cooling, body temperature cycling, and brain cooling
How does brain cooling work?
Arteries carry hot blood through capillaries in the sinuses to cool the blood down before it returns to the brain
