Plants Flashcards
Tropisms
Directional response to a stimulus
Nasty
Non directional responses to a stimulus
A taxic response
Movement of an organism towards/away from a stimulus
Kinesis
Non directional responses to a stimulus
Benefits of positive geotropism
Roots grow deep for fertile soil & growth
When photo receptors detect light
Auxin is released in meristems. Sunlight causes auxin to move away, causes cell elongation. Cells grow towards the light.
Benefit for shoots positive phototropism
-grows towards the light so better photosynthesis
- avoid shading if other plants
- more exposure to pollinators
How does auxin work
Auxin works by gathering in te lower half of the stem. In roots auxin will shorten the cells in the underside, causing the root to bend downwards.
In stems auxin lengthens the cells on the underside. Bending the shoot to point upwards
Photoperiodism
A plants response to change in day length. If plant has lots of Pr- it understands it’s night/winter
The most reliable cue used for animals
Photoperiod- length of daylight (identifying the time of year, as it reflects the seasons)
A plants directional response to a stimulus
Tropism
A plants non directional response to a stimulus
Nasty
Animal directional response to stimulus
Taxis
Animal non directional response to a stimulus
Kinesis
Gravity
Geo
Light
Photo
Chemical
Chemo
Touch
Thigmo
How does auxin affect roots
Slows growth, cells shorten and root bends downwards
How does auxin affect shoots
Speeds up shoot growth, Cells lengthen, shoot bends up wards
Current
Rheo
Meristems
Growth tissue present at the tips = apical, at stem branches =latteral
What causes migration
Maturation and breeding, environmental cues, predators, food supply
Advantages of migration
- favourable temp so less e used
- grow larger/stronger so better defense
- successful reproduction so genetic variation and survival increases
- constant food supply
Disadvantages migration
-may get lost
- predators
- uses up e (huge energy investment)
Navigation methods
- path intergration,
Smell,
Trail following
Mental maps
Piloting
Communication
Magnetic fields
Ocean and river currents
Intraspecific relationship
Interactions between individuals of same species. These can be cooperative or aggressive
What’s intraspecific competition
- have same needs and niches and there for me have competition for resources
Teritory
Defined area defended from individuals of same species
Defending area costs energy and time so benefits are:
Safe space to court, breed, grow
Raise young. Food shelter water (good to reproduce)
Strategies to reduce competition
Social hierarchies
Home range terotories
Altruistic behaviour
Increasing welfare of others, whilst putting themselves in danger
Kin selection
Showing altruisms to only family
Advances of hierarchy
Adaptive advantages for group, e.g. list, time and energy spent fighting, more energy and time for hunting feeding and breeding.
Parental care
Animals, very in the extent, they care for the young. 2 strats one r and K
r
Large numbers of offspring produced, little care is provided
K
Lots of care, few offspring produced Young have behaviour patterns that serve to reduce aggressive behaviour.
Advantages of biological clock
Anticipate environmental changes to maximise feeding time, avoid predators and competition
Biological clock
A natural internal timing system which occurs without any external cues and controls the organisms activity
Endogenous
Frequency not the exact same as environmental factors. Deviates from natural rhythm
Exogenous
Controlled by environmental cues
Biological rhythms
Regular, predictable patterns of activity or behaviour in living organisms
Circadian rhythm
Biological rhythm with a period of 24 hrs
Circalunar
Influenced by moon phases, 29.5 days
Circannual rhythms
Influenced by changing seasons, 365 days
Biological rhythms help organisms regulate
Essential processes like reproduction, metabolism, and behaviour
Biological rhythm
A cycle of events that is controlled endogenously (internally)
Endogenous rhythms
Don’t match exactly with external environments
Zeitgebers
Environmental cues that prompt us
Entrainment
The constant adjustment of the endogenous mechanism which means the animals are kept in exact synchronisation with the environment
Phytochrome
A protein that regulates the time in which a plant flowers. There are two types, the red light absorbing form (Pr) and the far red light absorbing form (Pfr). During daylight hours Pr is converted to pfr. At night the absence of red light causes the pfr to slowly convert back to pr
Interspecific relationships
Interaction between different species in a biological community
Interspecific relationships
Interaction between different species in a biological community
Interspecific relationships
I
Gauses principle of competetige exclusion
When two or more species occupy the same ecological niche, each species moves into slightly different measures or one species prevails, and the other is excluded becoming extinct in that habitat
Exploitation
An overarching term that describes the relationship where one species benefits positively, and one is harmed negatively
Avoid predation
Behavioural responses, camouflage, chemical, and structural defences, mimicry Batesian and mullerian
Parasites
Ectoparasites
Endoparasites
Social parasites
Reproductive parasites
Slave parasites
Mutualism
Benefits both
Commensalism
One benefits one is unharmed
Amesnsalism
One is unharmed the other is harmed
Parasitic relationship
Parasites, benefits, and exploits a host who is harmed
Territorialism
Defending and maintaining a specific area for resources mates and rearing offspring
Courtship
Behaviours that lead to successful breed in and reproduction in animals
Intraspecific relationships
Interactions between individuals of the same species
Linear hierarchy
hierarchy that occurs in a social group when the individuals are ranked from highest to lowest or from ‘alpha’ to ‘omega’
Advantages hierarchy
- more reproduction opportunity
-safer from predators/ better defence - more food and better hunting
Disadvantages hierarchy
Weaker members become extinct from population
- more Intraspecific competition for resources as group grows
-increased risk of spreading disease
How to remove zeitgeber
Place organism in constant / 24 hr darkness. With no zeitgeber / entrainment, the rhythm becomes free- running and shows weta’s natural endogenous rhythm
Phase shifting
Entrainment involves a process called phase shifting, in which the start of the rhythm / activity is advanced or retarded.
Phase shifting can be accomplished using an appropriate environmental cue. Often this cue is light (or absence of light).
Phase shifting
Entrainment involves a process called phase shifting, in which the start of the rhythm / activity is advanced or retarded.
Phase shifting can be accomplished using an appropriate environmental cue. Often this cue is light (or absence of light).
Phase shifting
Entrainment involves a process called phase shifting, in which the start of the rhythm / activity is advanced or retarded.
Phase shifting can be accomplished using an appropriate environmental cue. Often this cue is light (or absence of light).
Mimicry
Adaptive resemblance between unrelated species
Free running
Behaviour rhythm that occurrs independently of external changes
