Unit 1: Chapter 5 + 6 Flashcards
Adaptations
Is a genetically controlled structural, behavioural or physiological feature that enhances the survival of an organism in particular environmental conditions
Maladaptive
The adaptation no longer supports the environment it lives in
Tolerance range
Every organism contains a tolerance range for environmental factors that is a variation in which organisms can survive
Tolerance limits
They are the extremes of the range that species can survive in any further than that and the species will most likely die
What does an organism experience at its tolerance limits?
Physiological stress
Limiting factor
Any condition that approaches or exceeds the limits of tolerance for an organism
What determines tolerance range?
Structure and physiology
How do mulgara survive in arid environments/
They have higher medullary thickness causing very concentrated urine
They produce dry faeces
Reduce insensible water loss by exhaling cooler air
Very few sweat glands
Avoid desert heat by being nocturnal
Have fat stores in their tail
How can water be gained?
Through food
Through liquid intake
Metabolic water
Metabolic water
When carbohydrates and fatty acids are oxidised in an animals body, the main end products are carbon dioxide and water
How can water be lost?
Through the skin via sweat and diffusion
Faeces and urine
Insensible water loss
Milk for young
Insensible water loss
The loss of water through the lungs and their passages, usually unnoticeable
Surviving by dormancy
Frogs bury themselves deep underground to avoid the arid environment
Molluscs close their shell very tightly to preserve water
Dormancy
An inactive state in which breathing rates and heart rates are minimal and energy needs are greatly reduced
Surviving by moving around
Some species cope with drought by moving around from affected areas to areas where conditions are more favourable
Surviving through offspring
Some species produce drought resistant eggs and when the waterhole dries up the adult dies but the egg survives until the waterhole is filled up again
How do plants prevent water loss?
Water tappers (deep roots) Waxy cuticle Reduced number of stomata Sunken stomata Glossy leaves Small, narrow, cylindrical leaves Leaf margin (thickness) Vertical orientation Folded leaves No visible leaves Phyllode (leaf that isnt a leaf) Shedding leaves Producing drought resistant seeds
Transpiration
Is the loss of water vapour by evaporation from moist surfaces inside the plant
How do animals survive in freezing temperatures?
Produce antifreeze substances such as glycerol, amino acids and sugars
Burrowing underground
Converting fat into energy which produces heat
Hibernation
Blubber below skin (mammals in water)
Countercurrent systems
Thick coats
Countercurrent exchange
The blood coming from the core warms the blood coming back to the core to prevent it from cooling the organs and at the same time cools the blood going out so the heat lost from the skin is minimised
How do plants survive in freezing cold?
They have a higher concetration of ion in the cell and therefore have a lower freezing temp then the water is drawn out because there is a higher concentration of water inside the cell becuase ice has formed which lowers the freezing point even more
Biomimicry
is the practice of learning from and being inspired by nature’s best ideas to achieve technological advances, expressed in new dseigns, products and processes
Examples of biomimicry
Burrs and velcro - burrs hook onto stuff easily and are hard to remove and velcro was based off this
Lotus leaves and paint - lotus leaves have tine microscopic bumps that help remove dirt when it rains and new paint was designed to do this
Sharks and ships - Sharks have tiny overlapping scales called denticles which were mimicked on ships to reduce drag
Beetles and water bottles - beetles have hydrophilic tips and hydrophobic sides so the fog is turned to water and runs down the back and the drinkbotlle does the same
Physical processes of heat gain
Radiation
Conduction
Convection
Radiation
Heat is transferred from a warmer object to a cooler one but requires no physical contact
Convection
Is the process of heat transfer resulting from mass movement of the air or water past exposed areas of the body when they are at different temperatures
Conduction
Is heat transfer by immediate physical contact with another object at a different temperature
Physical processes of heat loss
Sweat
Insensible water loss
Evapouration
Is the conversion of liquid water to vapour
Evaporative cooling
Is the process of liquid from the skin (sweat) being evapourated by warmer air around the body thereby cooling the body down
Insensible water loss
Water lost as vapour from the lungs and passageways and the skin pores
Core body temperature
The internal temperature of the body
Physiological processes of heat gain
Shivering
Heat produced by metabolism
Vasoconstriction
Piloercetion (hair on end)
How does shivering help gain heat?
When muscles shiver, almost all energy of contraction is converted into heat energy
How does the metabolism cause heat gain?
Cellular respiration produces heat as well as glucose and carbon dioxide and ATP
Basal metabolic rate
The level of metabolism needed to maintain the living state in a person at rest, fasting and in a thermo-neutral environment. The base amount of energy required to complete bodily processes
Vasoconstriction
Narrowing of the blood vessels that results from contraction of the muscular walls of the vessels.
How does vasoconstriction cause heat gain?
By narrowing the blood vessels less heat is brought to the skin and therefore less heat is lost through the skin and therefore conserving heat
How does piloerection cause heat gain?
When the hair stands on end a layer of air becomes trapped and becomes an insulator between the skin and the external environment therefore conserving heat by preventing heat loss through skin.
Physiological processes of heat loss
Vasodilation
Cooling by evapouration (sweating)
Hair lowered
Decrease in metabolic rate
Vasodilation
Widening of blood vessels that results from relaxation of the muscular walls of the vessels.
How does vasodilation cause heat loss?
Vasodilation opens the blood vessels bringing warmer blood to the skin and allowing heat to escape through the skin, therefor causing heat loss
How does evaporative cooling cause heat loss?
Sweat needs heat energy to turn from liquid to gas and uses the heat in the blood vessels to turn sweat into water vapour and therefore cooling the body down
Homeostasis
The maintenence within narrow limits of a stable internal environment in the face of changing external conditions
Behavioral activities for heat gain
Vigorously exercising
Soaking in a hot bath
Putting on warm clothing
Standing in front of a heater
Behavioural activities for heat loss
Removing clothing
Cold shower
Resting in the shade
Sitting in frontof a fan
What is subject to homeostasis?
Temperature
Blood glucose
Water
Internal environment
The environment of cells inside the body of multicellular organisms
Ambient temperatures
The temperature outside the body
Peripheral surface temperature
The temperature of the skin
What affects body temperature?
Air temperature
Level of physical activity
Food intake
Endothermic
The organisms in which body temperature comes from internal metabolic heat.
Ectothermic
The organisms that rely on an external source of heat
Thermoregulation
The regulation of body temperature which ensures the balance between heat gain and heat loss so that body temperature is kept relatively constant
Stimulus response model
The process is undertaken by homeostatic mechanisms to keep the body in homeostasis
Diagram of stimulus-response model
Stimulus Receptor Modulator/control centre Effector Response
Stimulus
A stimulus is a change in the level of an internal environment
Receptor
Is the structure that detects the change and sends information to the control centre
Control centre
Evaluates change against set point for that variable and sends signals to the effector about the correction needed.
Effector
The effector adjusts its output to make the required correction
Response
The response is the corrective action taken
Negative feedback
A process in which the body senses a change in a variable and activates mechanisms to reverse the change so that internal conditions within the body are maintained within narrow limits.
Positive feedback
A process in which the body senses a change in a variable and then is increasingly amplified and increases the deviation from an ideal level.
Diagram of dropping core temperature
- Stimulus - Decrease in body temp below normal
- Receptor - Decrease detected by thermoreceptors in skin, organs and hypothalamus
- Control centre - Hypothalamus sends signals via nerve and hormonal systems to effectors
- Effectors - skeletal muscles, blood vessels in skin, cerebral cortex, body cells
- Response - Shivering, vasocontriction, behavioral changes, increase in metabolic rate
Negative feedback
Diagram of rising core temperature
- Stimulus - Increase in body temp above normal
- Receptor - Increase detected by thermoreceptors in skin, organs and hypothalamus
- Control centre - Hypothalamus sends signals via nerve and hormone systems to effectors
- Effectors - sweat glands, blood vessels in skin, cerebral cortex, body cells
- Response - Increase in sweating, vasodilation, behavioural changes, decreased metabolic rate
Negative feedback
Thermoreceptor
The receptor that detects temperature change in the core body temp
Hyperthermia
Increased body temperature in which homestasis fails and excessive internal heat is produced so that heat gain is greater than heat loss
Hypothermia
Decreased body temperature in which homestasis fails and excessive internal heat is lost so that more heat is lost than heat gained
Hyperthyroidism
An overactive thyroid gland which increases the basal metabolic rate of an affected person
Hypothyroidism
An underactive thyroid gland which decreases the basal metabolic rate of an affected person
What functions is water necessary for?
Making up plasma
Sweating
Wastes
Absorption of nutrients
Osmoregulation
Is the process of controlling water content of the human body and its solute concetration
Osmoreceptor
The receptor that detects water loss/gain in the body
Diagram of low water levels
- Stimulus - Decrease in water levels or increase in solute concentration
- Receptor - Osmoreceptors in hypothalamus detect change
- Control centre - hypothalamus signals the release of ADH hormone and signals the thirst centre
- Effectors - Kidney tubules become more permeable to water or thirst behavior is stimulated
- Response - increased reabsorption of water, decreased urine volume, water intake by drinking
Negative feedback
Antidiuretic hormone ADH
Acts on cells lining the collecting sucts of the kidneys and makes them more permeable to water
Diagram of high water levels
- Stimulus - Increase in water level or decrease in solute concentration
- Receptor - Osmosregulators in hypothalamus
- Control centre - Hypothalamus sends signal to inhibit release of ADH hormone
- Effectors - Kidney tubules become less permeable to water
- Response - Decreased reabsorption of water from kidney tubules, increased urine volume to expel water
Negative feedback
Blood glucose levels
The level of glucose in the blood
Insulin
Produced by the beta cells and facilitates the transport of glucose into some body cells.
Glucagon
Produced by alpha cells and acts on liver cells to mobilise their glycogen stores and release glucose.
Glycogen
The form in which glucose is stored in the tissue of the body
Diagram of low blood glucose
- Stimulus - Decrease in blood glucose
- Receptor - Alpha cells of pancreas
- Control centre - Alpha cells of pancreas secrete the hormone glucagon
- Effectors - Liver cells and body cells
- Response - Liver cells release glucose from glycogen, other cells make glucose
Negative feedback
Diagram of high blood glucose
- Stimulus - Increase in blood glucose
- Receptor - Beta cells of pancreas
- Control centre - Insulin sensitive cells of hypothalamus, beta cells of the pancreas secrter the hormone insulin
- Effectors - Liver cells and body cells
- Response - Decrease in blood glucose by uptake by liver cells and conversion to glycogen, uptake by body cells
Negative feedback
Pancreas
Is the organ which is responsible for the secretion of insulin and glucagon therefore responsible for the maintaing of blood sugar levels
Type 1 diabetes
An autoimmune condition when the insulin fails to be produced by the beta cells and the body cells cannot take up glucose from the bloodstream
Type 2 diabetes
A chronic disease where insulin is produced but the body cells of a person do not respond to it, they are insulin resistant
Hyperglycemia
When the blood glucose levels rise above the normal limtis
Hypoglycemia
When the blood glucose levels fall below normal
