Plants and Animals - Biology 2023

Etiolation

Rapid plant growth at the expense of strengthening tissue, caused by gibberellins.

Mullerian Mimicry

Where several poisonous species have similar colourations

Internal timing system that continues without external cues, and control (to some extent) the timing of activites of plants and animals

Biological Clock

Antibiosis

Inhibition of the growth of bacteria by the production of growth-inhibiting substances (antibiotics) by fungi

Active at dawn and dusk

crepuscular

Entrainment

Forcing the free running period to follow an external pattern

When the onset of the period of the rhythm is changed (either earlier or later) so that entrainment occurs

Phase Shift

Active during daylight

Diurnal

Driven by external stimuli (environmental cues)

Exogenous

Day neutral plant

A plant that flowers independently of the day length or seasons

Pulvinus

Site of Turgor Changes. It is a small fleshy elbow or hinge which is located at the leaflet base.

Nastic Movements Direction

Non-Directional

Hyponastic Response Regulator

Ethylene

Epinastic Response

The downwards bending of leaves or other plant parts, resulting from growth of the upper side of the petiole and leaf.

Nyctinastic Movement

Occurs in plants in response to the onset of darkness.

What are Nastic Responses caused by?

Turgor changes in the pulvinus Plant Growth

What does auxin do?

Promotes secondary thickening of stem/root, Promotes elongation and differentiation, Promotes cell division

Abscission

The shedding of various parts of an organism, such as a plant dropping a leaf, fruit, flower, or seed

What triggers flowering in long day plants?

The presence of Pfr at sunrise - indicates that the night was short

Phytochrome that absorbs red light

Pr

Phytochrome

Molecule that initiates many different physiological responses in plants, such as germination and flowering

Importance of photoperiodism

Important in the developmental responses of plants to certain lengths of light and dark periods.

Photoperiodism

the regulation of seasonal activity by day length, or photoperiod.

Photoperiod

Day length

Phytochrome system role

To detect changes in photoperiod

Critical day length

The period of light that tends to initiate flowering in plants.

Why do roots and shoots respond differently to gravity?

Different sensitivities to auxins

Ethylene

Promotes ripening of fruit. Promotes abscission

Abscisic acid

Is involved in opening and closing of the stomata on leaves. Also promotes and maintains seed dormancy by inhibiting cell growth.

Cytokinins

Hormones which promote cell division/mitosis in young fruit.

Gibberellins

Plant hormone that promotes stem elongation and is also involved in flowering and seed germination.

Cause of plant growth towards/away from a stimulus

Uneven distribution of auxins along the plant root/shoot (uneven intensity of stimulus on plant)

High auxin concentrations in shoot cells.

Promotes cell growth/elongation.

High auxin concentration in root cells

inhibits cell growth/elongation.

Auxins

A class of plant hormones which have an important role in many growth and behavioural processes in a plant's life cycle.

Tropism

A plant growth response towards or away from a stimulus.

Dominance Hierarchy Pro

Decreased conflict/infighting between individuals in the group

Disadvantages of Large Social Groupings (3)

Increased competition for resources, Increased chance of spreading disease, Reproduction interferences (e.g infanticide)

Advantages of Large social groupings (7 - D,E,H,M,P,S,-)

Defence of Resources (Defence). Rich learning environment for offspring (Education). Locating and obtaining food (Hunting). Assembly for mate selection (Mating). Protection from predation (Protection). Division of Labour (Sharing). Population regulation

Mutualism Interaction

Both Organisms benefit

Commensalism interaction

One organism benefits and the other is not affected

Parasitism / Exploitation interaction

One organism benefits and the other is harmed

Competition interaction

Both organisms are harmed

Co-operative behaviours Con

Close Proximity increases chances of infighting

Territory / Territoriality (Pros + Cons)

The active defence of an area where an organism or group lives. Pros:

• Safe space for young

• No competition for resources Cons:

• Aggressive behaviours displayed when defending territory risks injury

• defence of territory uses a lot of energy that could be used for other essential activities, e.g hunting.

Home Range

Wider area that an animal will use for resources and hunting which is not actively defended

Polygyny

Males mate with several females

Polyandry

Females mate with several males

Polygynandry

Males and females both breed with several different partners

Allogrooming

Social Grooming: Grooming of one another in a group.

Purpose: Social bonding and maintanence of hygiene.

Maintenance of Dominance hierarchy

Aggressive behaviours from Dominant individuals, Submissive behaviours from less dominant individuals

Why are Ritualised Fighting Behaviours used?

Aim is to get the other individual to 'back down' to prevent the risk of injury.

Orthokinesis

A form of kinesis where the speed of movement of the individual depends upon the intensity of the stimulus.

Klinokinesis

A form of kinesis in which the rate of turning of the individual depends upon the intensity of the stimulus.

Taxis

Directional response of an animal to the intensity of a stimulus.

Photo - prefix

Light

Gravi- or Geo- Prefix

Gravity

Rheo

Water current

7 cues of Navigation

Visual, Sonar, Magnetic Fields, Scent, Solar, Celestial, Water Current

Thigmo- Prefix

Touch

Klinotaxis

The use of 1 sense organ

• used to continually sample the environment and compare

• when positive, the organism will change direction whenever the 'signal' (stimulus) is weaker than previous samples.

• Organism will move is a zig-zag line of motion towards or away from a stimulus.

Tropotaxis

2 Sense organs (Bilateral Sense Organ) to undergo simultaneous comparison of receptors.

• Organism will move in a smooth line towards or away from a stimulus.

Homing

The inherent ability of certain animals to return to a given place, when displaced from it, through unfamiliar territory, often over large distances.

Migration

The regular and repeated mass movement of animals for breeding or avoidance of environmental / climactic extremes.

Kinesis

Non-directional response of an animal to the intensity of a stimulus

R-selected species attributes (4)

Occurs in unstable environments. Small body size. Low energy to raise. Highly fluctuating population size

Hyponastic Response

Upward bending of the leaves and the elongation of the petioles.

Hyponastic Response benefits

Promotes Cell Expansion. Restores Natural Gas Exchange.

Abcission

The shedding of various parts of a plant

Agonistic Behaviours

Behaviors which cause, threaten to cause or seek to reduce physical damage.

What do agonistic behaviours include (5)

Threats. Displays. Retreats. Placation. Conciliation.

What is Intraspecific competition?

An interaction where members of the same species compete for limited resources

What does intraspecific competition lead to?

A reduction in fitness for both individuals

Is inter or intraspecifc competition stronger?

Intraspecific competition

Why is intraspecific competition stronger

Members of the same species have very similar resource requirements

What is the carrying capacity (K) of a population

Maximum number of individuals of a particular species that an environment can support.

What happens when a populations numbers are above the carrying capacity (K)

The population will experience a negative population growth until the carrying capacity is reached

What is direct competition

Individuals directly compete with one another in pursuit of a resource. This may involve fighting, stealing, or claiming a territory.

What does exploitive competition involve

Individuals depleting a shared resource and both suffering a loss in fitness as a result.

Where does apparent competition occur?

In populations which are predated upon.

What does interference competition involve?

Individuals directly competing with one another.

When does contest competition take place?

When a resource is associated with a territory or hierarchical structure within the population

What happens to population dynamics in contest competition?

Relatively stable population dynamics

Why is the population dynamic of contest competition relatively stable?

The number of territories, and thus the breeding population in an area, stays the same over time, producing a similar number of new individuals every breeding season.

What does scramble competition involve?

More equal distribution of resources than contest competition, and occurs when there is a common resource pool that an individual cannot be excluded from.

What population dynamic does scramble competition lead to?

Unstable population dynamics

Why does scramble competition lead to unstable population dynamics?

When resources are divided equally, very few organisms obtain enough of the resource to survive and reproduce which can cause population crashes.

When does indirect competition occur?

Either, through a common limiting resource, or between two species which are preyed upon by the same predators

What is a territory?

The area with defined boundaries that an animal of a specific species consistently defends against members of the same species and occasionally members of different species.

What is a home range?

The area which individuals or a group of animals habitually use for essential resources but do not necessarily defend

What determines the size and location of a territory?

The number of individuals defending it, their strength and status

Why do animals defend territory

To acquire and protect a food source, nesting sites, mating areas, or to attract a mate.

How does territoriality affect fitness?

an increase in individual fitness or inclusive fitness of the animals expressing the behaviour.

What is ritualised aggression?

A series of postures, vocalisations, and displays which solve territory disputes without actual fighting.

What is a hierachy?

An established order of individuals in a particular group of animals .

What is a hierachy dependent on?

Factors such as their position in the food chain, the numbers in the community, the nature of individuals in the hierarchy e.g. herbivores or carnivores, access to resources, and adaptability to changing conditions

What is mimicry?

Mimicry is a form of defence against predators.

What is Batesian Mimicry?

The model is dangerous and the mimic has evolved similar features but is harmless.

What is Mullerian mimicry?

Two or more poisonous species share one or more common predators and have come to mimic each others warning signals.

What is Aggressive Mimicry?

Predators share similar features with a harmless model, allowing them to avoid being correctly identified by their prey