Topic 4 Flashcards Preview

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Flashcards in Topic 4 Deck (49):
1

Habitat

The natural home of environment of an organism

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Environmental factors

The various factors that produce the particular conditions in a habitat
Can be classified as biotic and non-biotic

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Biotic factors

Living
Humans, predators, competitors, parasites

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Abiotic

Non-living
Humidity, solar radiation, atmospheric gases, wind, air temp., salinity, soil and water chemistry

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Niche

The specific area where an organism inhabits
The role or function of an organism or species in an ecosystem
The interrelationship of a species with all the biotic and abiotic factors affecting it

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When an animal feeds

Diurnal- by day
Nocturnal-by night
Crepuscular- dawn and dusk

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Tolerance range

The particular environmental conditions in which a particular species can successfully live and reproduce

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Limiting factor

Any condition that approaches or exceeds the limits of tolerance for an organism is a limiting factor for that organism

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Adaptation

Genetically controlled structural, physiological or behavioural features that enable an organism to survive and reproduce in particular environmental conditions

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Structural adaptation

Physical features of an organism

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Physiological adaptations

Internal systematic responses to external stimuli in order to help an organism maintain homeostasis

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Behavioural adaptations

Activities that an organism does to help it survive in its natural habitat
Behaviours can be learned or instinctive

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Antifreeze

Glycerol, amino acids and sugars, or mixtures of substances are produced at the start of the freezing season.
These substances are released into their body fluid, which lowers the freezing point of their body fluids to below that of surrounding water temperatures. Thus, body fluids of organisms stay liquid

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Insulating layers

Endothermic animals do cellular respiration with chemical energy in food converted to heat energy
This heat is then trapped by a layer of fat under the skin, thick fur or feathers.
Prevents heat from escaping the animal

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Endothermic

Able to maintain their own body temperature

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Hibernation

Metabolism slows down considerably and breathing rate drops
Body metabolism is significantly reduced and body temperature drops
Amount of food required for animal to survive winter is reduced

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Countercurrent exchange

An outgoing artery is paired with an incoming vein
Blood coming from the body core to the skin is warm. Blood flowing from the skin back to the body core has been cooled.
Heat in the blood coming from the core flows to the blood coming from the skin so that the venous blood doesn't cool internal organs and muscles
Blood moving to skin is reduced and loss of heat across the skin is also reduced

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Huddling

Reducing amount of surface area that is exposed to the open air, reducing heat loss by radiation and convection

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Sweat glands

Secrete sweat which travels up to the sweat duct, through the sweat pore and onto the surface of the skin.
Evaporative cooling- evaporation of a liquid, typically into surrounding air, cooks an object or liquid in contact with it,
The sweat evaporates which causes heat loss via evaporative cooling, thus cooling the animal.

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Evaporation rate

Depends on the humidity of the air and it's temperature
The greater the temperature difference, the greater the evaporative cooling effect
When temperatures are the same, no net evaporation of water so no cooling effect.

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Piloerection in mammals

The erector pili muscles contract, lifting the hair follicle upright and making our hair stand on end, acts as an insulating layer and trapping heat
Air is not a very effective insulator, so it has a very limited ability to convey heat away from a warm surface like the epidermis

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Cold water adaptations

Thick layers of blubber under their skin to insulate their bodies and prevent heat loss.
Fat may be deposited around organs and oil in bone fat.

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Counter-current systems to warm blood

An outgoing artery is paired with an incoming vein
Blood coming from the core body to the skin is warm
Blood from the skin to the core body is cool
The blood coming from the core body to the skin flows through the artery and in close contact with the vein, so the blood flowing towards the skin is cooled down
This decreases the concentration gradient between the body and outside environment, reducing heat loss
The blood flowing from the skin to the core body flows through the vein, the vein is in close contact with the artery, the blood flowing back to the core is warmed and maintains body temperature.

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Biomimicry

The practice of learning from and being inspired by natures best ideas to achieve technological advances, expressed in new designs, products and processes
Inspiration may be an observation of an energy efficient action or structure in a plant or animal

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Homeostasis

The maintenance of a relatively stable internal environment within narrow limits
Involves monitoring levels of variables and correcting changes in these levels, typically by negative feedback
Temperature, blood glucose, water, ions, ph of arterial blood, blood pressure, urea in plasma

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Internal environment

The fluid surrounding living cells within a multicellular organism

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Negative feedback system

Process in which the body detects a change in a variable and activates mechanisms to correct that change so that internal conditions within the body are maintained within narrow limits
The response is opposite in direction to that of the original stimulus

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Stimulus

Change in the level of an internal variable

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Receptor

The structure that detects the change and sends information to the control centre

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Control centre

Evaluate the change and sends signals to the effector about the correction needed

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Effector

Adjusts its output to make required corrections

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Response

Corrective action taken

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Radiation

Heat is transferred from the warmer object to the cooler object with no physical contact

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Conduction

Small heat loss from a warmer to cooler object by touch

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Convection

Heat transfer from the mass movement of air moving past exposed areas of the body when each is at a different temperature

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Evaporation

Conversion of liquid water to vapour, requires input of energy, source of heat loss from body

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Shivering

Alternate contraction and relaxation of small muscle groups to convert energy into heat energy

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Metabolism

Minimum amount of heat generated internally to maintain the living state in a person at rest, fasting and in a thermoneutral environment.

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Vasoconstriction

Hypothalamus sends nerve impulses, causing the ring of muscle around the arteriolar to constrict, therefore blood flow to capillaries under skin is reduced

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Vasodilation

The ring of muscle around the arteriolar relax, blood flows close to the skin surface and heat loss in increased

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Endothermic

Heat produced by own internal metabolic processes

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Exothermic

Body heat comes from an external source like the sun

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When homeostasis fails

Heat stroke, hypothermia, thyroid disorders

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Osmoregulation

Maintenance of constant internal salts and water concentrations in internal fluids

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Blood glucose

Insulin and glucagon control blood glucose levels
Produced by cells in the pancreas called islets of langerhams

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Insulin

Made in beta cells of pancreas
Released when blood glucose levels rise
Causes blood glucose to be taken from the bloodstream by the body's cells

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Glucagon

Made by Alpha cells of pancreas
Released when blood glucose levels fall
Causes liver to convert stored glycogen into glucose which enters bloodstream

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Type 1 diabetes

Body can't produce insulin, die to destruction of islet cells in pancreas
Cells don't receive a signal to take up glucose from blood
Too much glucose in blood

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Type 2 diabetes

Cells of muscles and liver do not respond to insulin