Exam Flashcards
What are the biological scales from smallest to largest?
Molecules -> Cells -> Tissues -> Organs -> Organisms -> Populations -> Communities -> Ecosystems -> Biotas
What are the spatial scales from smallest to largest?
Local -> Regional -> Continental -> Global
What are the temporal scales from smallest to largest?
Acute -> Chronic -> Generational -> Macroevolutionary
Acute Time Scale
Minutes to hours; ex. Daily fluctuation in temperature, hottest day on record.
Biological Response to Acute Pressures
Behavioural adjustment (e.g. sit in water); Physiological response (e.g. sweating); Death; Immediate response.
Chronic Time Scale
Weeks to years; ex. Seasonal fluctuation in temperature, hottest seasons on record.
Biological Response to Chronic Pressures
Migration, Acclimatization, Death; Change in physiology to adjust set points in relation to prolonged changes in the environment.
Generational Time Scale
Multiple generations; ex. Gradual climate change (e.g. ice ages), Rapid climate change.
Biological Response to Generational Pressures
Habitat tracking, Adaptation, Extinction.
Conformers
Allow internal environments to follow external changes; as external environment changes, internal environment changes in the same manner.
Regulators
Attempt to maintain constant internal environments in the face of varying environmental conditions; internal environment stays consistent along zone of stability, changing at extremes.
Hyper-Regulation
Maintaining an internal environment higher than external environment.
Hypo-Regulation
Maintaining an internal environment lower than external environment.
What processes are regulated by regulators?
Ions, temperature and metabolic depression can be affected.
How do mammals conform/regulate?
Regulate ions and temperature; some species go into hibernation or torpor where metabolic depression occurs.
How do birds conform/regulate?
Regulate ions and temperature; some experience torpor.
How do reptiles/amphibians conform/regulate?
Conform to temperature; regulate ions.
How do fishes conform/regulate?
Conform to temperature; regulate ions; exceptions include icefishes.
How do invertebrates conform/regulate?
Conform to ions and temperature.
Where do polar bears release heat?
Eyes and mouth.
Where do elephants release heat?
Along entire body, especially large trunk and ears.
Why would photoperiod evolve to be a trigger for anti-freeze protein production, if it’s actually an adaptation to changing temperature?
The antifreeze proteins are readily available when they are needed. Photoperiod is also more consistent than temperature. Maybe it’s easier for cues based on photoperiod to evolve.
What materials must arctic plants/animals exchange?
Gases (O2 for metabolism), Nutrients (foods), Wastes (balance ion composition).
How does exchange occur in cells?
Across membranes; rate depends on membrane surface area; amount needed depends on volume. In multicellular animals, every cell must be in contact with aqueous environment (interstitial fluid) where dissolved substances can be exchanged. Complex animals must have circulatory fluid to carry things to interstitial fluid. Respiratory and digestive systems have direct contact with external environment.
Homeostasis
To varying degrees, animals maintain relatively constant internal conditions in the face of a fluctuating external environment. Neural/hormonal processes are involved in keeping internal variables constant. Regulatory systems based on negative feedback.
Negative Feedback
Results in a decrease in a variable that is too high or an increase in a variable that is too low.
What happens in endotherms when temperatures rise?
Vasodilation, increased sweating and panting, behavioural changes that limit heat gain. (signals from hypothalamus)
What happens in endotherms when temperatures fall?
Vasoconstriction, shivering, behavioural changes that limit heat loss. (signals from hypothalamus)
Temperature Set Point
Temp. set point is not fixed but may vary on a daily/monthly/seasonal cycle. Hibernating endotherms do not lose complete control, but maintain a lower set point.
Positive Feedback
Not as common because it pushes system father from initial state (ex. oxytocin stimulating uterine contractions in mammals. Must be a natural endpoint.
Acclimatization
Adjustment by individual organisms to chronic stresses.
Adaptation
Evolution of populations across generations under natural selection.
Range of Tolerance
Temperature range where the organism functions best.
How do temperature changes affect the molecular/macromolecular level?
Can alter cellular function (especially in ectotherms). An increase in temperature increases molecular movement and can denature proteins if extreme. A decrease in temperature can make an enzyme still and unable to function.
Lactate Dehydrogenase (LDH)
Final enzyme in anaerobic glycolysis. If cell temperature changes, LDH activity or rate of lactate production will change. Ectotherms modify LDH activity to maintain cell function by altering expression of LDH isoforms.
How are cell membranes affected by a change in temperature?
In ectotherms, cell membrane composition is changed to maintain fluidity.
Homeoviscous Adaptation
The maintenance of relatively constant membrane fluidity regardless of tissue temperature.