Learn: plant and animal responses

INNATE BEHAVIOUR:

Genetically hardwired in an organism and can be performed in response to a cue without prior experience.

LEARNED BEHAVIOUR:

Behaviour an organism develops as a result of experience.

Stimulus

physical or chemical change in the immediate surroundings of the living organism that elicits a response from plants and animals.

Response

the conscious or unconscious reaction of the living beings to the stimuli, which is mostly an involuntary activity that benefits the organism.

Thigmo

touch

Photo

light

gravi

gravity

chemo

chemical

hydro

water

thermo

temp

rheo

water currents

Negative response

away from

positive response

toward

taxis

indicates animal response

tropism

indicates plant response

positive/negative rheotaxis

positive = moving against the direction of the water current, negative = moving with the direction of the water current

orientation response

an involuntary reaction of a human or animal to a new, unexpected, or important change in the environment

klinotaxis

A form of directional orientation in animal behavior where an organism moves toward or away from a stimulus by making alternating side-to-side movements of its body or head.

By sampling and comparing stimulus intensities during these lateral sweeps, the organism determines the direction of the source.

This tactic is most commonly used by animals that possess a single intensity receptor or those whose sensory organs are too close together to make simultaneous spatial comparisons.

Because they lack paired receptors, they must rely on temporal comparisons over time rather than spatial comparisons.

tropotaxis

Shown by animals with paired intensity receptors.Under multi-source stimulation, orientation moves to an intermediate point based on relative intensity.

If one receptor is covered, the animal moves in spirals, known as circus movement. The animal continuously steers itself so that the sensory input (such as light, chemicals, or temperature) remains equal on both receptors.

kinesis

refers to a non directional movement or change in activity rate of an organism in response to a stimulus. involves a change in the rate or turning rate depending on the intensity of thestimulus

orthokinesis

the speed of movement is directly related to the intensity of the stimulus

klinokinesis

the rate of turning is directly related to the intensity of the stimulus

phototropism

Phototropism is a directional growth movement in response to a unidirectional light source.

mechanism of phototropism

Photoreceptors in plant cells detect light, and plant hormones, such as auxins, are directed to the side of the stem that is further from the light.

The accumulation of auxins on the shaded side of the stem causes the cells in this area to elongate at a greater rate than those on the opposite side of the stem.

As a result, the stem curves in the direction away from the side of the accumulated auxins and toward the direction of the light.

geo/gravitropism

Geotropism (or gravitropism) is a growth movement in response to gravity.

Gravitropism ensures that roots grow into the soil and that shoots grow toward sunlight.

Growth of the shoot apical tip upward is called negative gravitropism or positive phototropism, whereas growth of the roots downward is called positive gravitropism.

mechanism of geotropism

When amyloplasts settle to the bottom of the gravity-sensing cells ( known as statocytes) in the root or shoot, they physically contact the endoplasmic reticulum (ER). This causes the release of calcium ions from inside the ER. This calcium signaling in the cells causes transport of the plant hormone indole acetic acid (IAA) to the bottom of the cell.

In roots, a high concentration of IAA inhibits cell elongation. The effect slows growth on the lower side of the root while cells develop normally on the upper side. IAA has the opposite effect in shoots, where a higher concentration at the lower side of the shoot stimulates cell expansion and causes the shoot to grow up. After the shoot or root begin to grow vertically, the amyloplasts return to their normal position.

Thigmotropism

Thigmotropism describes plant growth in response to touch or contact with a solid object.

Positive thigmstropism is demonstrated by climbing plants or vines, which have specialized structures called tendrils. Example: Passionfruit plant

When the tendril makes contact with an object, sensory epidermal cells on the surface of the tendril are stimulated. These cells signal the tendril to coil around the object.

Auxins are also involved in the differential growth of tendrils.

mechanism of thigmotropism

Tendril coiling is a result of differential growth as cells not in contact with the stimulus elongate faster than the cells that make contact with the stimulus.

A greater concentration of the hormone accumulates on the side of the tendril not in contact with the object.

The twining of the tendril secures the plant to the object providing support for the plant. The activity of climbing plants provides better light exposure for photosynthesis and also increases the visibility of their flowers to pollinators.

nastic response

Nastic Responses are non-directional responses to the intensity of a stimulus.

Because nastic responses are non-directional they cannot be described as positive or negative.

They do not involve elongation of cells so are not growth responses.

May involve rapid, reversible movements, often resulting from localised changes in turgor(water pressure).

mechanism of nastic responses

The response is similar to nervous response in animals.

Electrical signals are generated by the gradient in certain ions such as Potassium(K) and Calcium(Ca).The movement in ions cause a flow of water into or out cells, changing the turgor pressure in cells.

This will cause a change in the position of leaf parts, e.g dropping of leaves in Mimosa, or sleep movements in flowers and leaves. Many leaves have a petiole which has the function of holding leaves upright so they are exposed to maximum amount of sunlight.

At the base of each petiole is a structure called a pulvinus which is responsible for the nastic response. The diffusion of K+ causes a limited number of cells (those in the pulvini) to respond by either taking water up or expelling it.

That mechanism, ultimately, is the movement of potassium ions (K+) into and out of cells, with water following by osmosis.

The result is that cells become more turgid, larger, if K+ and water move into them, and flaccid, collapsed, smaller, if K+ and water move out of them.

seasonal migration

the regular, periodic movement of living organisms or humans from one habitat or region to another in response to changing seasons, weather, or resource availability

mass movement

the travel of large groups of people to a new region to live

cue

signals or signs that let an animal know that it is time to do something

visual cues and landmarks

A mental map is carried in the mind and includes known landmarks, such as rivers, trees, and mountains. animals will often follow the topography (shape) of land to track familiar landmarks and find their orientation in response to home

magnoreception

This ability to use the earth's magnetic field is known as magnetoreception. It helps animals to orient themselves, find their way along migration routes, and even locate specific destinations.

Compass: Animals can detect the direction of the magnetic field lines, helping them determine north, south, east, or west.

Map: Variations in the magnetic field strength and inclination (the angle between the field lines and the Earth's surface) can provide positional information, allowing animals to determine their location on a larger scale.

solar compass

Sun's Movement: The sun's position in the sky changes throughout the day, requiring animals to adjust their heading to maintain a consistent direction.

Time-compensated sun compass: Many migrating birds and insects are believed to use a time-compensated sun compass. This means they have an internal clock that allows them to factor in the sun's movement and maintain a steady course.

Polarized Light: Some animals may also use polarized light patterns, which are perpendicular to the sun's azimuth (its direction above the horizon), to aid in navigation, especially when the sun is obscured by clouds.

STAR/ STELLAR COMPASS

Using the position of the stars as a compass and a sense of timing to navigate. A sense of timing iis required as the stars will move throughout the night so that the organism needs to be able to adjust its path accordingly.

chemical navigation

This is a sensitivity to a chemical or chemical gradient that allows an organism to find it way back to nesting sites/ food / spawning sites.

biological rythms

inked to cyclical changes in the environment.

Examples of rhythms are daily, annual, tidal, lunar, semi-lunar and compound.

daily rythms

Linked to the rotation of the earth on its axis every 24 hours, resulting in the cycle of day and night.

Animals are active for only part of the day-night cycle.

Nocturnal: most active at night

Diurnal : most active during the day

Crepuscular: active during dusk and dawn.

annual rythms

Caused by the combined effects of the earth orbiting the sun and the earth's tilt causing the seasonal cycles over a period of 365.25 days.

Triggered by changes in photoperiod (daylength)as the year progresses(exception at the equator)

Examples are hibernation, aestivation, migration, reproduction.

tidal rythms

Caused by the gravitational pull of the moon (and to a lesser extent the sun) coupled with the rotation of the earth on its axis.

There are thus two tides a day.

Organisms living in the inter-tidal zone alternatively inhabit two environments-land and sea.

Immersion by sea is a time for feeding and reproduction.

Exposure to air at low tide presents the threat of dessication, extremes of temperature and sometimes osmotic flooding by rain.

lunar rythms

Linked to the rotation of the moon around the earth.

Animals synchronise their behaviour to the phases of the moon.

semi lunar rythms

Associated with the rotation of the moon around the earth but there are two cycles every lunar month.

Spring tides(high tides are highest) and neap tides (small low tides)occur a few days after new and full moon.

Organisms inhabiting the lower shore are only uncovered about every 15 days and those at the upper shore may only be covered every 15 days- organisms show twice -monthly rhythms.

actogram

In Actograms, animal activity (e.g. use of running wheel) is represented as bars.

These bars are placed within a 24 hour timeframe so we can see rhythms.

endogenous

Endogenous means growing, produced, or originating from within a system, organism, or body rather than from an outside source

exogenous

Exogenous means originating or produced from outside an organism, system, or structure

dormancy

a natural survival period where growth, development, and metabolic activity slow down or temporarily stop. This minimizes metabolic activity and conserves energy.

The plant, seeds or buds do not resume grown until a change in the daylength and temperature provide favourable conditions.

VERNALISATION

The process by which certain plants use a prolonged period of cold to promote flowering.

Ensures that flowering occurs in Spring and Summer.

Gibberellins are the hormones important to breaking dormancy.

photoperiodism

This is the response of a plant to the relative lengths of daylight and darkness.

It is based on a system that monitors the day/night cycle.

The photoreceptor involved in this is a blue-green pigment called phytochrome.

mechanism of photoperiodism

Experiments showed that a light-sensitive protein pigment called phytochrome is involved in a plant's ability to track day length (or, more accurately, night length).

This pigment molecule occurs in two forms, an active form and an inactive form. The molecule converts from one form to the other depending upon the type of light it receives.

In total darkness, the active form gradually reverts to the inactive form. The length of time in darkness determines the ratio of the two forms. The ability to monitor this ratio is how a plant "counts" the number of hours of darkness.

When this ratio reaches a certain level (which depends upon the species and variety), the plant's darkness requirements are met. Only then will the leaves will release the plant growth regulators to travel throughout the plant and initiate the flowering process.

short day plants

Plants that flower when the photoperiod is less than a critical day length.

SHORT DAYS AND LONG NIGHTS. PERIOD OF DARKNESS HAS TO BE CONTINUOUS.

At the end of the long night, all Pfr is converted into Pr which promotes flowering.

long day plants

Flower when the photoperiod is greater than a critical daylength.

LONG DAY AND SHORT NIGHT. PERIOD OF DAYLIGHT HAS TO BE CONTINUOUS.

Lots of Pfr build up during the day, hence not all Pfr is converted to Pr by the end of the night. The remaining Pfr promotes flowering.

day neutral plants

A plant that flowers regardless of the length of the period of light it is exposed to.

social groupings

an aggregation of individuals of the same species living together in a structured, cooperative manner

advantages of large social groupings

- protection from adverse factors and predatoers

- assembly for mate selection

- locating and maintaining food

- defence of resources againist other group

- division of labour amongst group members

- richer learning envieonment

- population regulation (eg breeding restrictied to a dominant pair

disadvantages of large social groupings

- increased competition for resources between group members as group size increases

- increased chance of the spread of disease and parasites

- inteferance with reproduction

intraspecific competition

Competition that occurs among organisms of the same species.

Members of the same species have the same niche( biological rhythm, food requirements, need for shelter, finding a mate).

Competition is therefore more intense within the group.

Intraspecific competition tends to have a stabilising influence on the population size.

Intraspecific competition can be classified as being "Density dependent". This means that:

(i) If the population gets too large, competition increases, so the population falls.

(ii) If the population decreases, intraspecific competition decreases.

relationship between intraspecific competition and natural selection

Intraspecific competition is the driving force behind Natural Selection as those with the favourable phenotypes are more likely to survive and reproduce to pass on those favourable traits.

agressive behaviour

encompasses conflict over resources as well as predatory behaviour.

agnostic behaviour

Behaviour that is associated with conflict situations among members of the same species.

Could include: aggression, threats, avoidance or appeasement.

Usually highly ritualised so that it is not easily misinterpreted

Important role to play in reducing physical conflict and injury.

cooperative behaviour

Cooperative behaviour is when two or more individuals work together to achieve a common goal.

Goals include defence, food acquisition, rearing young.

altruistic behaviour

self-destructive (or risky) behaviour for the benefit of others. e.g the meerkat lookouts are at risk but group overall gains.

kin selection

altruism towards relatives (kin). Promotes survival of shared genes e.g. lions help raise young of others, young elephant mums get help from relatives to care for calves.

territories

Organisms usually have a personal space around them

Home Range: Geographical area that animals seldom leave, nest in and search within for food and mates.

Territory: An area which the animal/ breeding pair / group marks and defends.

Lek : a territory used only for mating

hierarchies

A ranking system within a group of animals. Alpha at the top, omega at the bottom.

Determines access to food, water and mates.

Influenced by:

Size, maturity, male vs. female, having offspring, knowing territory (vs. being a stranger), healthy.

dominance hierarchies

Males are usually not related and will challenge the dominant leader for top position.

Female-led groups( Matriarchical system) are usually based on mother-daughter relationships. E.g bonobos, elephants, wild dogs

Some primates(hamadrayas baboons) and sea lions have harems and fight off any males trying to steal their females.

linear hierarchies

In a linear hierarchy one individual dominates all the other individuals in a group, a second dominates all but the first, and so on down to the last individual who is dominated by all the others.

Also known as the pecking order.

ANTHROPOMORPHISM

Anthropomorphism is the attribution of human characteristics, emotions, and behaviors to animals or other non-human things (including objects, plants, and supernatural beings).

what is the purpose + definition of courtship

animal courtship refers to ritualistic behaviors that species perform before mating to attract and select the best partner for reproduction. purpose: Ensures animals are of the same species

Allows sexual selection so improves gene pool

Overcomes the usual defensive or aggressive behaviour allowing the male and the female to get close enough to mate

May cause animals/birds to start nest building

May trigger ovulation in some animals

MONOGAMY

one male and one female pair bond

POLYGYNY

one male competes for and breeds with many females

POLYANDRY

one female breeds with many males and male cares for offspring.

POLYGYNANDRY

umerous male/female partnerships.

r strategy (many offspring)/ rate of reproduction

Production of large numbers of eggs with little investment of time and energy in raising the offspring.

There is little risk to parents but many of the offspring do not survive.

k strategy (few offspring) do not exceed carrying-capacity of environment

Production of few offspring with a large investment of time and energy in raising them.

This strategy is a higher risk to parents but has a higher survival rate for offspring.

Brood parasitism

Brood parasitic birds lay their eggs in the nests of others, sparing themselves the expense of rearing their own young.

The bird affected by this brood parasite suffers as all their time is invested in rearing the chick of the parasitic bird, while their chicks suffer.

community relatiomship

A species niche is its role in the biological community.

All organisms interact with other members of the community in some way.

Interspecific relationships are between different species.

interspecific

Occurs when resources (e.g. food, water, living space, nest sites) become limited.

gause' principle

NO TWO SPECIES CAN OCCUPY THE SAME NICHE INDEFINITELY IN THE SAME HABITAT'

mutualism

Relationship where both species benefit.

COMMENSALISM

Relationship where one species benefits while the other species neither benefits nor is harmed.

EXPLOITATION - PARASITISM

One individual (parasite) feeds off the other living species (host).

Ectoparasites - feed from the outside e.g. mosquitoes and leeches.

Endoparasites - live inside the host e.g. liver flukes feed on blood, tapeworms feed on digested food.

Batesian Mimicry

a survival strategy where a harmless or edible species (the mimic) evolves to look like a dangerous, toxic, or foul-tasting species (the model) to trick predators into leaving it alone

Mullerian mimicry

a biological phenomenon where two or more harmful, toxic, or unpalatable species evolve to look like each other to share protection against predators

Allelopathy

Plants prevent other plants from growing by secreting poisonous substances into the ground e.g. The Black Walnut tree produces juglone which is a respiration inhibitor.

ADVANTAGE: ensuring that they have all of the available space and nutrients. Reduces inter-and -intraspecific competition for resources.