Biology - Plants & Animals

Altricial young

enter the world blind and helpless. This is characteristic of animals who are well protected by their parents

Precocial young

enter the world in an advanced state and are able to run

Symbiosis

close, prolonged association between two or more different species

Amensalism

One organism is destroyed while the other organism remains unaffected

taxis

directional movement in animals

tropism

directional movement in plants

positive

movement towards a stimulus

Pulvini

Responsible for controlling Nastic responses. Cells actively pump K+ ions out of the cell. This causes a loss of water by osmosis.



The loss of water means the lower cells become flaccid and lose their rigidity, and the cells on the lower surface expand and plump up, causing the leaves to fold up.

negative

movement away from a stimulus

nastic response

non-directional response in plants. Rapid, reversible movement responses by parts of plants to changes in abiotic factors

Nyctinasty

the closing of petals of the flowers at night

kinesis response

non-directional response in animals

orthokinesis

a change in the speed of the movement

klinokinesis

a change in the rate of turning

positive phototropism

response growing towards the light

phototropic

plants shoots are...

auxin

controls the direction of growth

adaptation

an evolutionary process by which an organism becomes better suited to its environment

chemotropism

a growth movement in response to chemical concentration gradient

commensalism

relationship between two species whereby one species benefits while the other is neither harmed nor benefited

ecological niche

the role of a species in its habit or everything that it

environment

all external conditions, both biotic and abiotic, affecting organisms

evolution

genetic changes in a populations that over generations lend to new types of organisms; maybe divergent or convergent.

Gause's competitive principle

no two species share the same ecological niche without one eventually out-competing the other.

plumule

first shoot (plants)

radicles

first root (plant)

Macroevolution

large changes in gene pool over a long period of time, as in the formation of a new species, extinction of a new species, extinction, adaptive radiation

microevolution

small changes in the frequency of alleles in a gene pool over successive generations

statoliths

starch grannules (plastids) which allow a plant to detect gravity (also known as amyloplasts)

stimulus

an aspect or change in an individuals external or internal environment that causes some sort of response, something in the environment detected by a receptor or sensor

hormone

chemical secreted into a plant or animal body and transported to another part where it affects growth or activity

etiolation

the condition of a plant that has received insufficient light, where it has excessively long and weak stems and small leaves

Cytokinin

plant growth substances that promote cell division, or cytokinesis, in plant roots and shoots

gibberellin

regulate growth and influence various developmental processes, including stem elongation, germination, dormancy, flowering, etc

abscisic acid

Inhibits plant cell division in the buds and seeds.

ethylene gas

a gas that is also a plant growth hormone, regulating fruit ripening, growth and ageing

photopigment

a coloured chemical that is bleached when it absorbs light, and triggers a nerve impulse when it spontaneously returns to its normal state; known as rhodophin in animals

germination

sprouting of seed or spore

vernalisation

the induction of flowering by period of chilly

Bud dormancy

the process in trees where bud formation is triggered by shortening days but buds remain small and undeveloped

annual plant

a plant which completes its life cycle from seed germination to seed production, followed by death within a single seam, regardless of how many times reproduction occurs

Phytochrome

a blue-green protein pigment, found in most plants, acting as the light receptor for several processes, including photo periodism in plants and germination in plants and the germination of some seeds and spores

dormancy

a state of temporarily reduced metabolism, as in seeds, but common in terrestrial animals

homing

the ability of animals to find their way home over unfamiliar territory

navigation

the methods used by animals to find their way over unfamiliar territory

free running period

how long the cycle runs in the absence of all environmental cues

entrainment

the synchronisation of biological clock with exogenous cues (zeitgeber)

diurnal

an organism that is active during the period of daylight

perennial

plant that completes it growth and reproduction cycle over many years, often reproducing every year for many years

zeitgeber

an exogenous cue that synchronise an organisms endogenous rhythms to the rhythms of the environment, e.g. the sun or the light dark cycle

exogenous

a stimulus originating within the external environment, e.g. light and dark, is called this

short day plant

plants that require a period of dark exceeding a certain length

long day plant

plant that flowers when exposed to dark periods of less than critical length

crepuscular

an organism that is active during the periods of dawn and dusk

photoperiodism

the physiological reaction of plants and animals to the presence and absence of light

territory

an area occupied by an animal, which it defends aganist other animals

parasitism

one species lives in or on another larger species, feeding off but not killing

photoreceptor

a cell specialised to detect light

return migration

animals that move to a winter feeding ground and return to their home range for spring which is where they have their breeding sites

magnetic fields

animals using the earth magnetic field to detect magnetic north to determine its position in reference to a particular goal

solar compass

using the suns position to navigate

Sound (Sonar)

They emit a sound which bounces off objects back at them. The speed of the bounce allows them to be able to position themselves in relation to that object.

Chemical cues

Some animals are able to use chemical (scent) trails to find their way like pheromones

Visual clues

Animal recognises familiar landmarks and uses them to guide them to their destination

celestial compass

using the star to navigate.

circadian

biological rhythm which is daily

circatidal

biological rhythm which is tidal

circalunar

biological rhythm which is monthly

circaannual

biological rhythm which is annual or yearly

biological clock

internal time keeper/ pace maker which controls timing in living organisms

daily rhythm

rhythm with a period of 24 hours

altruism

some members may give up their right to reproduce to assist another breeding pairs offspring

predation

relationship in which in one species kills and eats another

interspecific competition

competition between different species

intraspecific competition

competition between members of the same species

migration

seasonal mass movement of animals from one region to another

Home range

An area that an animal uses for food, but will not defend.

r-strategist

reproduce early in life; many small unprotected offspring

K strategist

reproduce late in life; few offspring; care for offspring

courtship behavior

behavior that allows males and females of the same species to recognize each other and prepare to mate

pair bond

a durable and exclusive relationship between a male and a female

Monogomy

mate with a single male or female

Polygamy

When males or females have multiple partners

polygyny

When a male mates with multiple females

polyandry

When a female mates with multiple males

Thermo

temperature

Hydro

water

Geo or Gravi

gravity

Thigmo

touch

Photo

light

Chemo

chemical

Rheo

water current

stems and phototropism

Stems are positively phototropic and therefore grow towards the light. Response ensures that plant leaves have maximum light for photosynthesis.

roots and phototropism

Roots are negatively phototropic and grow away from light to prevent them from drying out.

stems and geotropism

Stems are negatively geotropic, shoots from germinating plants grow upwards (‘against’ gravity). Response ensures shoots grow towards the light.

roots and geotropism

Roots are positively geotropic, roots from germinating plants grow downwards (‘with’ gravity). The response ensures the roots grow down into the soil where it will anchor the plant and be able to obtain nutrients and water.

roots and hydrotropism

Roots are positively hydrotropic and grow towards water sources. This response increases the chances of plants obtaining water which is needed for turgor pressure, photosynthesis, transport and essential cell processes.

thigmotropism

Directional growth in response to rubbing on one side of the stem/tendril. Growth is inhibited on the side being touched, causing the plant organ to coil around the object being touched. Response to touch increases the chance of obtaining maximum light intensity for photosynthesis.

chemotropism

Roots can grow towards or away from chemicals in the soil. These chemicals may have been released by another plant.

Avoiding predation

Living in groups, safety in numbers through and deception through camouflage