Everything I need to know for plant and animal responses: Flashcards
Key terms/ memory things...
Taxis definition
- In response to what…
- How does it occur
Directional movement in response to a stimuli. Movement can be positive or negative
(Uses sensory organs/appendages to detect the strength of stimulus)
Kinesis definition
Non-directional movement in response to a stimulus
(randomly increases the chance of going into a favourable environment)
Orthokinesis
change in speed
Klinokinesis
change in rate of turning
Homing
The ability of an organism to find its way home over unfamiliar territory
Migration
Regular, often repeated and seasonal, mass movement of animals from one place to another, linked to feeding and breeding)
Day neutral plants
A plant in which flowering can occur irrespective of the day length
Endogenous
Rhythm controlled by an internal clock due to their DNA
Entrainment
The resetting of the biological clock on a regular basis, forcing it to take up the period of the environmental cue
Free running period
The period of a biological clock rhythm in the absence of external environmental cues
Auxin
Synthesised in the shoot tips and is responsible for cell elongation in the plant stem
Phase shift
When light/dark is altered, the phase shift is the amount by which the period alters
Photoperiodism
The response of an organism to changes in day length ( a photoperiod)
Phytochrome - during the day
Pr — Pfr
Phytochrome - during the night
Pfr — Pr
Long day plant phytochrome concentration
High conc of Pfr and this will initiate flowering
Short day plant phytochrome concentration
High conc of Pr (low conc of Pfr) initiate flowering
SCN
Cells in the brain which receive information from the retina in the eye and connect to the pineal gland
(Suprachiasmatic Nucleus)
Zeitgeber
An external/environmental cue that entrains an organisms biologial rhythms
(provides stimulus setting or resetting)
Tropism definition
Directional Growth in response to a stimuli - can be positive or negative
Nastic/ Nasty definition
Non- directional movement in response to stimuli. It is fast and reversible
How to tropism responses occur:
Auxin. It’s produced in the tips of roofs and shoots. In shoots it accumulated on the shaded/untouched side of the shoot, causing the cells to elongate and the shoot to grow in a certain direction. In roots auxin INHIBITS cell elongation, so growth will be in other direction (the shaded side contains more auxin and grow less, so the root bends away from the light).
How do nastic responses occur
Rapid change in the ion concentration (K+/ potassium ions) of cells. As the ions move out of the cells, so does the water through osmosis. This loss of water from the cell vacuole changes the Turgor pressure of the cell. This can be quickly reversed by the movement of ions back into the cells and increasing turgor pressure)
When this occurs in the cells on one side e.g of the ptiole/ leaf stalk the leaves will bend and move (e.g. venus flytrap).
Types of interspecific relationships:
Competition, Mutualism, commensalism, Parasitism, herbivory, predation
Types of intraspecific relationships:
Competition, Hierarchies, territories, Courtship/Pair bonding, Parental care
Types of mimicry:
Batesian - Mimics a toxic model, without having those traits itself
Mullerian = Two or more species have similar traits that predators have learned to avoid e.g. bright colors
e.g. markings of snakes (red, black yellow vs yellow, red, black etc)
Linear hierarchies
One individual dominates all the other individuals in a group, the second dominates all but the first, and so on, until the bottom, where one individual is not dominant over any others (e.g. pecking order)
Complex hierarchies:
Affiliations and subordinate groupings (more and less powerful) generally an alpha male in charge
(Maintained through dominance and submissive behaviours)
Competition: aggressive vs. agnostic behaviours
Aggressive = Threats or harmful actions towards another individual (inter and intra)
Agnostic= Between members of the same species, not always competition, and can be appeasement or avoidance
Monogamy + advantage
one mate during life time
= Shared cost of raising the young, defend and protect
Polygyny + advantage
male mates with multiple females
= Males increased reproductive success (but could reduce genetic diversity and cause inbreeding)
Polyandry + advantage
Female mates with multiple males
= Females have higher reproductive success
Polygynandry + advantage
multiple males mate with multiple females (e.g. a social group)
= Females increased reproductive success, greater genetic diversity, less competition of males, greater care of young from group
Parental care:
The investment of time and energy into raising offspring
K strategy definition
A small number of offspring + higher level of parental input
(fewer reproductive events, larger offspring, slow growing populations)
R strategy definition
A large number of offspring + little to no parental input
(many reproductive events, short lived individuals, fast growing populations,
Pros and cons of R Strategy
Pros = High chance of SOME individuals surviving due to large quantity. More energy into reproductive output, but less energy spent on parental care
Cons= Lower chance of survival per individual
Pros and cons of K Strategy
Pros = Increased survival and success of alleles being passed on (offspring can grow and reproduce)
Cons = Energy costs of raising young
Courtship in animals, purpose and benefits:
To facilitate atraction and mate with the oppostie sex (sexual dimorphism from displays)
Group living advantages and disadvantages:
Pros = Increases chance of survival, decreased predation, increases resource gathering and protection, group raises young together = offspring survival
Cons = Spread of disease, intraspecific competition, inbreeding
