Chemotropism (stimulus is a particular chemical such as toxins, acids)

Taxes are (rapid) movements either towards (positive, +ve) or away from (negative, -ve) an external stimulus.

The direction of the stimulus determines the direction of movement.

To orientate towards or away from the stimulus, the organism either determines the direction of the stimulus by moving a single sense organ and comparing relative intensities (klinotaxis), or the organism determines the direction of the stimulus by comparing using two or more sense organs or either side of its body and comparing the intensity of the stimulus (tropotaxis).

Kineses are non-directional movements in response to a stimulus, with the intensity of the stimulus determining the rate of movement (the direction of the movement in random, bearing no relation to the direction of the stimulus).

Orthokinesis, in which the intensity of the stimulus determines the speed or rate of movement - the rate is faster in unfavourable conditions and slower in favourable conditions

Klinokinesis, in which the intensity of the stimulus determines the rate of turning when moving - the rate is faster in unfavourable conditions and slower in favourable conditions.

Homing is a response in which an animal regularly returns to a nest site or a breeding nest/colony.

To do this successfully, the animal must be able to navigate and requires an internal clock,.

Migration is a response in which members of a species move from one geographic location to another isolated geographic location.

Typically, migration is an annual event in which animals migrate between breeding and feeding grounds. This may be between two different parts of a country or between two different parts of the world.

For some species, return migration occurs at different stages of their life cycle and not annually.

Migration is innate (adults do not teach their young where to go or how to get there). However, migratory experience over the years can improve success rate.

Laying down of fat layers to ensure energy supplies for the journey.

Μoulting of feathers and replacement with new ones (especially flight feather) to ensure maximum flight efficiency. The new feathers may include breeding plumage for the spring migration.

For long-distance migration to have evolved and continue to exist, the advantages/benefits must outweigh the disadvantages/costs. Migration offers greater reproductive success compared with non-migration.

Landmarks - the animal recognises familiar landmarks and uses these to guide it to its destination. This is more common when the animal is close to home.

Since the sun moves across the sky during the day, a long-distance migrant must compensate for the sun's movement. Therefore an internal clock is essential to keep track of time and allow the animal to change its orientation to the sun and therefore keep on course to its destination.

Stellar navigation (star patterns) - animals can use star patterns such as the constellations when moving at night. An internal clock is also required, to compensate for movement of the stars.

Magnetic fields - many animals are known to use Earth's magnetic fields to successfully navigate.

Chemical trails - animals may use scent trails to find their way to a destination

Sonar (sound reflection) - the ability to navigate using echolocation, emitting sound waves that bounce off objects.

Typically, a combination of methods may be used by an animal to successfully find its destination.

Can give plants support. Saves energy and materials by not needing to produce large amounts of the fibrous cells/ tissues normally needed to support the stem. This energy can then be used for other life processes.

Maximises higher light intensity to maximise photosynthesis and therefore increase growth.

Being higher gives greater exposure to pollinators, increasing opportunities for successful pollination.

Increased height about the ground also provides better dispersal opportunities for seeds.

Higher light intensity = higher temperature = higher chance of dehydration

Weak individuals that do not complete the migration have their alleles removed from the gene pool; only strong/best-adapted individuals get to compete the route and successfully breed.

If the day is long enough, P(far-red) accumulates and long-day plants flower.

If the night is long enough, P(red) accumulates and short-day plants flower.

Increased flower production and pollination opportunities increase chances of successful reproduction of the species.

Provides a comparatively safe place for mating, nesting and rearing offspring

Increases the chances of successfully reproducing, rearing young and surviving.

Energy demanding for monitoring and defending the boundaries

Potential physical risks/injuries resulting from boundary disputes

A home range surrounds a territory. It is shared with other groups of the same species and is where they forage for food. The home range is not defended.

Offspring is left on its own for a period of time, so there is a greater risk of death through heat loss, and they are more vulnerable to predation.

Forming and maintaining a group depends on behavioural adaptations of the individuals. These behaviours have been selected for, as they enhance survival and reproductive success.

Better defence against predators; young put on inside of herds.

Greater ability to find food, especially as a result of co-operative hunting

Greater ability to spot predators, as more eyes/ears are on lookout.

Increased intraspecfic competition, especially as group gets larger - this can result in poor health / reduced reproductive success / increased mortality.

Increased risk of the spread of disease resulting from close contact with others in the group.

Controlled access to mates, so some individuals do not get to breed (especially males).

Occurs when resources become limited. As individuals of the same species have the same resource requirements, infraspecific competition is typically more severe than interspecific competition.

Agonistic behaviour in groups results in the reduction of aggression.

This is seen in distinct postures/gestures/vocalisations that threaten another animal. These behaviours are understood and the threatened animal typically backs off / backs down or displays submissive behaviours, with the result that serious aggressive encounters are rare.

Agonistic behaviours tend to be ritualised, with dominant and submissive behaviours recognised and acted on by other members of the group.

Hierarchies occur when individuals have a specific rank (or status) within a group.

Only high-ranked individuals get to breed. Therefore only the alleles of the stronger individuals enter the gene pool / occur at higher frequency in the gene pool.

Rankings are typically determined by trials of strength. They may change over time.

Vocalisations and/or visual displays may be used to advertise the location of a territory, warn off others of the species and/or attract a mate.

Males unable to secure a territory typically do not secure a mate and breed. Therefore, their alleles do not enter the gene pool. Territories therefore act as population controls and enhance the gene pool, as only the strongest individuals get to breed and contribute their successful alleles to the gene pool.

Increases the chances of working together successfully to mate and rear offspring.

Large numbers of eggs are produced with little investment of time and energy in raising the offspring.

This strategy provides little risk to the parents, but has a low success rate.

Few offspring are produced with a large investment of time and energy in raising the offspring.

This strategy creates a higher risk to the parents, but is offset by a higher success rate.

A pair bond forms between the male and female as a result of courtship behaviour.

Courtship behaviour ensures that mating occurs between individuals of the same species and so maintains the isolation of the gene pool.

Courtship behaviours tend to be a series of repeated, ritualised activities and responses, typically initiated by the male.

In some species, a lek system exists in which males congregate in an area and display to watching females.

Typically only a few males will get to breed with the females, so contributing their favourable alleles to the gene pool.

In which numerous male/female partnerings occur within the social group and most adult assist with raising the offspring.
Adults do not typically raise the offspring.

In which males and females release gametes simultaneously, often in response to environmental cues, and fertilisation is external.

Both parents can share the duties of raising/feeding/protecting the young, which reduces the demands (eg, energy) on each parent and increases the chances of successfully raising the young until they are independent.

The main disadvantage is that the male does not have access to a range of potential partners, and therefore in unable to contribute his alleles in higher frequency to the gene pool.

The advantage of providing parental care is that the survival chances of the offspring until they are independent are improved.

The disadvantages of parental care is the costs to the parents - energy demands are high when feeding and protecting the young. In addition, the parents are at increased risk of harm/death when they protect the young from potential predation and/or weather events.

Allogrooming benefits the group as it establishes/reinforces social bonds and reduces the risk of aggression.