Environment and responses Flashcards
What are abiotic factors
Non living/physical eg Wind,humidity
Name 5 abiotic factors
Wind speed,Water,oxygen,Humidity, temperature, light intensity ,salinity,
What are biotic factors of environment
Influences /interactions with other living organisms eg competition ,exploitation,mutualism
Name the 3 types of biotic environmental factors and their examples
Competition - interspecific(between species )/intraspecific( within a species)
Exploitation -Predatory/herbivory/parasitism
Mutualism
What are photoreceptors
receptors that sense light so we ‘see ‘
What are chemoreceptors
detect chemicals - ie in nose/mouth so we smell and taste
What are mechanoreceptors
detect sound waves ie found in cochlea ear -detect sound waves so we ‘HEAR “
Name 3 types of receptors that organisms detect environmental stimuli
Mechanoreceptors - sound waves
Chemoreceptors- chemicals -
Photoreceptors - detect light
How do animals detect and respond to environment ( pathway)
Stimulus —picked up by receptor—via sensory nerves fibres to brain —brain sends out via motor nerve fibres to effector organs –produce a response to the stimulus (more complex animal brain the more complex pattern stimulus can be detected )
what’s innate behaviour
Instinct behaviour-Coded for by DNA/Genetics(genetically determined - not learnt)
what’s Learned behaviour
behaviour is not genetically acquired- is learned from experience or parents
What is mutualism
A relationship where 2 species both benefit from the relationship
What is taxes
The rapid directional movement of animals towards(+) or away (-) in response to an external stimuli. DIRECTION stimulus determines direction movement
What’s kinesis
Non directional movement of an organism in response to a stimulus with INTENSITY of the stimulus determining the RATE of movement ( not direction of the stimulus) - eg Slater moves slowly in damp atmospheres but quickly in dry to increase finding damp favourable conditions
Name animal orientation responses
Taxes
Kinesis
Homing
Migration
Name plant orientation responses
Tropisms
Nastic responses
What is a Tropism
Directional growth of a plant towards (+ve tropism ) or away(-ve tropism )) from a external stimulus -
What’s phototropism
directional growth of plant organs in response to light ie shoots growing usually towards light
what’s prefix photo stand for
light ie phototropism /phototaxis- movement plant/animal in response to light
What’s phototaxis
directional movement of an animal in response to light ie some algae detect light via sensitive eyespot and so move to regions of higher light to increase their photosynthesis
What’s gravi ( geo)tropism
directional growth of a plant in response to GRAVITY ie roots grow down or shoots grow away from gravity
What’s Geotaxis
DIRECTIONAL l movement of a ANIMAL in response to gravity ie some shellfish bury down into sand ( positive geotaxis - moving in direction GRAVITY )
What is homing
ability of an organism to REGULARLY find its way back to a nest site/breeding nest/colony ie salmon return to river they were born to spawn. Needs internal clock +ability to navigate
What is migration
seasonal mass movement of organisms from one geographical area( breeding ground) to another isolated geographical location ( feeding ground) and back . Usually a response to LOWER temperatures resulting in reducing food supply and is often triggered by a shortening day length.
INNATE response ( can improve over years though to improve success rate )
What is Thigmotropism
growth of an aerial PLANTorgan in response to localised TOUCH eg pea shoot curling around a pole
What is Chemotropism
growth of plant away form or toward aCHEMICALin the environment - eg roots growing away from a toxin in soil
What is hydrotropism
roots growing toward WATER
what is heliotropism
Tendency plants to grow in direction of sun movement - eg east to west ( sunflowers)
What are Auxins
A plant growth hormone that promotes growth by cell enlargement /elongation in plant shoots and germinating seeds. In HIGH concentration root cell elongation is INHIBITED by auxin . Gravity causes auxin to accumulate on lower side of roots
What is chemotaxis
directional movement of an animal in response to chemicals in their environment - eg female mosquito follow carbon dioxide gradients toward their prey , animals running away from smell fire 9 negative chemotaxis
Why does phototropism occur
uneven elongation of cells in growing tip of the plant - auxin made on tip - diffuses back down to zone elongation , so more auxin found on bottom shaded area shoot , causing greater elongation - steering shoot toward light
what does auxin do on
Plant hormone that stimulates growth by cell enlargement in plant shoots and germinating seeds. In High concentration stops growth , lower concentration increases growth
What is apical dominance
Apex at top tree makes large quantities auxin inhibiting growth of lateral ( side branches - near top ) . Lower down side branches exposed less auxin so stimulated to grow causing the Xmas tree shape
Name 5 plant hormones and effect
Cytokinins - made in roots and regulates cell division/growth
Auxins - see own slide
Gibberellins - stimulate cell elongation stems /cell division flowers/fruit/seeds
Ethylene- gas causing ripening fruit/seed germination/leaf loss
Abscisic acid - “stress” hormone - reduces water loss in times plant stress
What’s a Nastic response
Rapidly reversible movements of a plant in response to change in intensity of a stimulus (non-directional ) eg opening/closing flowers in response to light at night closing ( Photonasty ) ,Venus flytraps in response to touch (thigmonastic )
Cant be +ve or _ve as not directional
What is an adaption
are what an organism does to live successfully in its habitat and way of life.Each adaption has a purpose to live and survive
Name 3 different types of adaption and example
structural -aspects of body structure eg large grinding molars of cows
behavioural-aspects of behaviour of organism -stalking of prey by lions
physiological- aspects chemical processes body -anti-coagulants for blood sucking animals to thin blood eg mosquito
What’s an ecological niche of an organism
Way its adapted in response to the habitat it lives in
What is an adaptive advantage
Adaption that PROMOTES survival of organism by increasing chance of successful breeding and therefore contributing successful alleles into the gene pool
What’s the fundamental niche of an organism
What organism would occupy if ALL necessary Environmental conditions were met
What’s the realised niche of an organism
The actual niche the organism lives in
What makes up the niche of an organism
Combination of WHERE it lives( habitat) and HOW it lives( adaptions -structural ,behavioural,physiological)
What limits the fundamental niche
organism tolerance to abiotic factors ( ie wind, pH, heat etc)
What limits the actual niche
usually biotic factors ( especially interspecific competition)
What happens if 2 niches have a large overlap
competition severe ( greater overlap the greater interspecific competition )
What is Gause’s principle
When 2 niches similar one species will outcompete therefore eliminate the other
What is another name for Gauses principle
Competitive exclusion principle
What is the principle behind When 2 niches are similar one species will outcompete therefore eliminate the other
Gause’s principle
What are orientation responses
Responses that are innate allowing organism to avoid unfavourable environmental conditions /find favourable conditions
Name the orientation responses in plants
Tropisms and nastic responses
Name the orientation responses in animals
taxes and kinesis
What are Auxins
PLANT HORMONE produced stems and roots and diffuse down from tip to promote ELONGATION cells ( growth )
What does increasing concentration auxins do
Stimulates cell elongation to a certain level ( above this level it inhibits growth)
What happens if auxin concentration is unequal on stem side
One side will elongate more then other causing stem bending
What happens to auxin in phototropism
Light causes higher concentration of auxin on side away from light source so cells elongate one side more than other and so stems bend toward the light source (+ve phototropism )
What happens to auxin in roots
high conc. auxin inhibits cell elongation - and so auxin concentrates in lower side of root , inhibiting cell elongation on this side - roots bend down into soil( +ve geotropism )
What is klinotaxes
determination of a stimulus by moving a SINGLE sense organ and comparing relative intensities
What is tropotaxes
determination of DIRECTION of a stimulus by using 2 or more sense organs on both sides of body comparing the intensity of stimulus
What is orthokinesis
Intensity of stimulus determines speed /rate of MOVEMENT ( faster in unfavourable conditions/slower in favourable conditions )
What is it called when Intensity of stimulus determines speed /rate of movement ( faster in unfavourable conditions/slower in favourable conditions )
orthokinesuis
What is klinokinesis
intensity of stimulus determines rate of TURNING WHEN MOVING
What is the adaptive advantage of tropisms/kinesis/nastic and taxes
To MOVE organism to FAVOURABLE CONDITIONS ( and OUT of UNFAVOURABLE /HARMFUL conditions )
Name 2 things an organism must have to have a homing response
Internal clock and ability to navigate
Name 2 things an organism must have to be able to migrate
Internal clock and ability to navigate ( like homing)
Do animals need too prepare for migration
Yes
How do animals prepare for migration
Internal clocks set in action activities ie laying down fat for energy for the long journey or moulting old feathers for new flight feathers
For long distance migration to exist what needs to occur
Advantages/benefits outweigh disadvantage /costs
What risks occur with migration
Not enough fat so die as no energy , winds blow off course etc
What’s benefits migration
Avoid extreme winter climate with reduced food there, plentiful feeding at new site promoting breeding/survival and strong young
Does migration or non migration offer greater reproductive success
Migration
Name 6 types of Navigation
Chemical
Landmarks
Magnetic fields
Solar navigation ( sun compass)
Stellar navigation ( star patterns)
Sonar ( sound reflection)
What is landmark navigation
When animal recognises landmarks and uses to guide to destination ( usually when close to home)
What is Solar navigation
Animal uses sun as it moves east to west to navigate (by keeping a set angle to sun when moving will move in a straight line ). Needs internal clock
What must an animal using solar navigation have in long distance migration
internal clock as it needs to keep track of time and change its orientation to the sun to keep on course to its destination to compensate for suns movement
What is Stellar navigation
Use star patterns as constellations when move at night ( like sum need internal clock )
what is magnetic fields navigation
Using earths magnetic fields
what is chemical navigation
Using scent trails to navigate to a destination ie ants lay pheromone trail when forage
Sonar navigation
Using echolocation ( bats/dolphins ) emitting sound waves that bounce off objects
What is an innate response
not taught responses ( not learnt ). Genetic programmed
Are nastic responses fast or slow
Fast
Are tropism reactions fast or slow
Slow
What do we call animals active at night
Nocturnal
What do we call animals active in the day
Diurnal
What are animals called that are active at dawn &/or dusk
Crepuscular
Is orientation to Time innate or learnt
Innate
What controls activity patterns to time
Internal clock
What sets an animals internal clock
environmental cues ( Zeitgeber)-
What is the adaptive advantage of having activity controlled by environmental cues ( there’s 3 )
Allows organism to ANTICIPATE/predict ONSETof favourable conditions so gets maximum advantage of this ie feeding time.
Allows animals PREPARE activities ie migration so increases survival
Allows SYNCRONISATION- favourable conditions
When an organism activity is set to a particular zeitgeber what is this called
ENTRAINED to that environmental cue - ie most common is onset daylight diurnal organism get up
Are activities under internal clock endogenous or exogenous
Endogenous
What is free running period
length of time takes for an organisms endogenous rhythm to repeat ( return to same phase ) in the absence of environmental time cues .ie cyclical behaviour observed with NO external stimulus
If a free running period is >24hrs when does onset of activity occur
Later in the day
If a free running period is <24hrs when does onset of activity occur
Earlier in the day
What is a circadian rhythm
An endogenous rhythm - free running rhythm displays period of about 24 hours ( 1 day)
What’s cirannual
free running rhythm displays a period 365days ( 1 year)
What’s circatidal
Free running rhythm displays period 12hrs( 1 tide )
What’s Circalunar
Free running rhythm displays period 30days ( 1 month )
What’s circasemilunar
Free running rhythm displays period 15days
Can some activity be determined by external factors and what’s this called
Yes - exogenous rhythm
Give an example of an exogenous rhythm
Photosynthesis ( can only occur if enough light)
How do you know if an activity is endogenous or exogenous an organism
Place organism in constant conditions - and if activity continues and displays periodicity then its endogenous
What is photoperiodism
Response of plants to the changing of the length of night ( Length DARKNESS important )
How to plants exhibit photoperiodism usually
Flowering and loss of leaves - ie plants flower at a certain time of the year
What must plants be able to sense to tell what season they are in
The length of darkness
What are short day plants
Plants that require short days and long nights (flower when photoperiod is less than the critical length - 10hrs daylight /14hrs darkness)ie chrysanthemum
What season do short day plants flower
Winter
What are long day plants
require long days and short nights ( flower when photoperiod is longer than critical length -14hrs daylight and 10hrs darkness) ie sunflower
What season do long day plants flower
Summer
What are day-neutral plants
Plants that are relatively unaffected by the amount of light per day and will flower anytime of year ie tomato
What season do day neutral plants flower
All year
What controls the ability of plants to activate the photoperiod response
A pigment called phytochrome
What is phytochrome
A pigment that controls ability plants to activate the photoperiod response
What form(s) does phytochrome exist
2 forms :Pr ( PRed or P665)
Pfr ( Far Red or P725)
How does the pigment phytochrome work
Daylight is made from mainly red light ( wavelength 665nm) and night mainly Far Red ( wavelength 725nm)
Pigment phytochrome absorbs red light in day and converts Pr to Pfr. At night Pfr slowly converts back to Pr .
The length darkness determines whether a plant will flower - amount of each form of phytochrome acts like an hourglass so
Day long Pfr accumulates and so in long day flowers as less Pr so flower ???
Day short lots, night long-lots Pr accumulates so short day plant flowers
Give 3 reasons plants must keep track of time
1.Seeds germinate at time year most likely to survive
2.Seed masting ( seeds dropping at sametime ) increasing survival as not all seeds eaten
3. Plant flower sometime year when their pollinators active so highest number flowers for cross pollination so increasing genetic variation /species survival
What is an exogenous rhythm
controlled by an external stimulus
What is an endogenous rhythm -
controlled by biological clock /no environmental stimulus needed
What is a period of rhythm
Time taken to complete one cycle of activity
What is a phase shift
Occurs during entrainment - how much the activity/rhythm shifts forward or backward
What is entrainment
Resetting of the biological clock
What is Zeitgeber
The environmental cue that resets the biological clock
What is an actogram
special graph to show activity of an animal /plant during day and over many days -used to show periods rest and activity
