3.3 Plant and Animal Responses Flashcards
What is tropism?
A growth response towards or away from an environmental stimulus in one direction (plants)
What is auxin?
Auxin is a plant growth hormone that controls the tropic response, it causes elongation
How does auxin affect roots?
Low concentrations stimulate, high concentrations inhibit
How does auxin affect lateral buds?
Low concentrations stimulates, high concentrations inhibit
How does auxin affect stems?
High concentrations stimulate, low concentrations inhibit
What is etiolation?
When in low light shoots grow faster and the stem becomes elongated to maximise stem length so that the plant may grow to a lighter area.
Where does auxin accumulate?
The shaded/lower sides of the plant root/shoot
What is the mechanism of a plant working towards positive phototropism?
What are nastic responses?
Non-directional responses to stimuli (plants)
What is taxes?
The movement of the whole animal towards or away from a stimulus
What is Kinesis?
A non directional response to stimuli (animal)
What are the 3 main reasons for animals’ behaviour?
Food, Shelter, Mates
What are the mechanisms of gravitropism in seedlings?
What is gibberellin?
The hormone responsible for the germination of seeds, stimulation of flowering, and breaking dormancy in seeds and buds
What is homing?
The ability of an individual to return back to the home site
What is migration?
Annual mass movements made by animals from their breeding area to feeding area
What are the triggers to migration?
- A drop in temperature
- Days become shorter, which triggers migratory restlessness
- Innate genetic drive
- The desire to reproduce
What are the methods of navigation used in animals?
- Visual Cues
- Solar Navigations
- Magnetic fields
- Star Navigation
- Chemical Navigation
- Sound as sonar
How does solar navigation work?
It is an inbuilt clock that can help to determine direction, using the fact that the sun moves east to west during the day.
What is an exogenous rhythm?
A rythym controlled by the external stimuli detected by the organism
What is an endogenous rhythm?
A rythym controlled by an internal biological clock and maintained even when zeitgebers are removed
What is entrainment?
When biological clocks reset on a regular basis with zeitgebers, forcing it to take up the new period of environment
What are the adaptive advantages of circadian rythyms?
- Sychronise with food/prey
- Avoid Predators/unfavourable conditions
Biological clocks are?
Innate, genetically determined
What are the adaptive advantages of circaannual rhythms?
- Synchronise with seasons
- Breeding in favourable conditions
- Migrating to avoid unfavourable conditions
Photoperiods in animals are controlled by?
The pineal gland and SCN
What is a zeitgeber?
Environmental cues that train the internal biological clock
What is phytochrome?
A pigment in leaves that absorbs 2 wavelengths of light, Pr Pfr
What is a short-day plant?
Plants that require short days and long nights (low con. of Pfr)
What is critical day length?
The time of day length required for a plant to flower
What is a long-day plant?
Plants that require a long day and short night to flower (high con. of Pfr)
What does Pr absorb?
red light, from the sun
What does Pfr absorb?
Far-red light, night only has far red light
Describe the phytochrome diagram
How is the light detected?
By the leaves, which uses florigen to pass the messages to the buds
Describe short day plants in winter
Pr accumulates to high levels, stimulating them to flower (due to low con. Pfr)
Describe long day plants in summer
Pr reaches low levels , stimulating them to flower (due to high con. Pfr)
What are interspecific relationships?
Interactions with other species
What are intraspecific relationships?
Interactions between one species
Describe mutualism
Species A and B benefit
Describe commensalism
Species A benefits, Species B is not affected
Describe antibiosis
Species A is harmed and Species B is not affected
Describe exploitation
Species A benefits, Species B is harmed
Describe alleopathy
Occurs in plants only, Species aA benefits, Species B is harmed
Describe competition
Both species are harmed
Describe the specifics of exploitation
Grazing: Plants eaten by many organisms
Predation: Predator v Prey
Parasitic: Parasites take resources from the host
What is Gauses’ principle of competitive exclusion?
“When two species have exactly the same way of life (ecological niche) they will not be able to co-exist.”
What is interspecific competition is reduced by?
Animals creating small differences in niches, such as eating on different parts of a tree or leaf, being nocturnal vs. diurnal, plants growing away from one another
What is an Agnostic Behaviour?
Any social behaviour related to fighting (broader than just aggressive behaviour)
What is ritualised fighting?
Non lethal organised fighting within a species to make sure there are is a winner and a loser without serious damage to damage survival
When does the most vicious fighting occur?
Individuals that can’t really hurt each other
When does the most intense competition occur?
- Interspecifically
- Between the same sex when needing a mate
How do species alleviate intraspecific competition? Why do they want to do this?
Creating hierarchies and territories. Competition benefits no-one so species will try to avoid it when possible to ensure their survival.
What is a home range?
An area that an animal moves around to collect resources or travel across. it is not defended (Neighbourhood)
What is a territory?
An area of the home range that is defended and marked (house)
What are some of the adaptive advantages of territories?
- Reduces direct competition
-ensures enough space and food for each animal holding territory - The most successful male has the most territories, meaning more genetically superior off spring
How do animals mark their territory?
- Vocal, birds singing
- Mark with urine
- Special scent glands
- Waving claws/visuals
