Term
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Definition
Self contained functional units
Made up of all biotic and abiotic factors
To consider: the flow of energy in a system and the cycling of elements within the system |
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Definition
| A group of interbreeding organisms of one species in a habitat at the same time. |
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| All the populations of different organisms living and interacting in a particular place at the same time. |
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Definition
| The place where a commuinity of organisms live. |
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Definition
| All the conditions and recources needed for an organism to survive, reproduce and maintain a viable population. |
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Definition
| Need to know the abundance of the individuals of a species in a given space. Samples are used: RANDOM SAMPLING USING QUADRATS or SYSTEMATIC SAMPLING USING TRANSECTS |
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Term
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Definition
Point quadrat and frame quadrats |
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Term
HOW TO DETERMINE THE NUMBER OF QUADRATS TO USE |
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Definition
| Larger the number of quadrats; more reliable the results. However recording number of species is time consuming if there is lots. BALANCE BETWEEN VALIDTY OF RESULTS AND TIME AVALIABLE. |
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Definition
| Depends on size of organisms in the area and distribution of them. e.g species not evenly distributed in groups, lots of quadrats of a small size. |
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Definition
For statistically significant results; random sampling must be used |
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Definition
| Avoid bias. e.g species of plant living on grazed land: take tow fields close to each other to minimise abiotic factors. Lay out 2 tape measures at edges of sampling area. Position quadrat by getting coordinates generated by a computer or table. |
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Term
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Definition
Horizontal bar - two legs to fix to the ground. There are 10 holes at regular intervals on the bar and a long pin is dropped through the holes. Whatever species touches the pin is recorded
*Some point quadrats have 5/6 legs instead of holes and pin |
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Definition
| Square frame divided into equal sub divisions. Abundance of each species in recorded by recording what is in each subdivision. |
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Definition
| Used when there is some form of change in communities of plants or animals, using transects. Can be used to determine how a changing abiotic factor affects distribution and characteristics. |
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Definition
| String/tape stretched across the ground in a straight line. Any organism over the line is recorded |
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Definition
| A meter wide strip: two lines parallel to each other. Species occuring within the belt is recorded. |
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Definition
ACFOR
Frequency
Percentage cover |
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Term
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Definition
Abundant;Common;Frequent;Occasional;
Rare
Subjective test, not quantitve so no information on accurate denisty but it's quick and easy - not time consuming |
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Definition
| Likelyhood of a specific species occuring in aquadrat. e.g if it occurs in 15/30 quadrats it's occurence is 50% - quick idea and general distribution no information onf density and detailed distribution |
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Definition
| Estimate the area that each species takes up in a quadrat; rapid data collection, individual plants don't need to be counted. Quatative data collected: Difficult if plants overlap in quadrat |
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Definition
| Large sample size. Many quadrats used. Mean of all samples obtained. Larger the number of samples, the more representative of the community as a whole results |
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Definition
- Catch animal
- Mark animal (non toxic marking, doesn't make the animal more visible to predators, mark doesn't come off easily
- Return animals to habitat
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Term
WHY MARK RELEASE TECHNIQUE? |
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Definition
| Most animals are mobile so move when approaches by humans. Difficult to identify using quadrats and transects |
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Term
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Definition
N= S1 x S2 / R
N: Estimated population size
S1: Number of animals in first sample (marked and released)
S2: Total number of animals in 2nd sample
R: Number of marked animals in sample 2
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Term
ASSUMPTIONS MADE FOR LINCOLN INDEX - 1 |
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Definition
- Proportion of marked to unmarked in 2nd sample is the same as proportion of marked to unmarked of the whole population
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Term
ASSUMPTIONS MADE FOR LINCOLN INDEX - 2 |
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Definition
- The marked individuals have enough time to distribute themselves evenly amongst the rest of the population
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Term
ASSUMPTIONS MADE FOR LINCOLN INDEX - 3 |
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Definition
- Definate boundry so little immigration or emmigration if any at all
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Term
ASSUMPTIONS MADE FOR LINCOLN INDEX - 4 |
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Definition
- Few, if any, deaths or births, so recapture must be done within a relatively short period of time
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Term
ASSUMPTIONS MADE FOR LINCOLN INDEX - 5 |
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Definition
- Non toxic marking or marking that makes the animal more visible to the rest of the population. The markings can't come off easily either
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Term
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Definition
| Stage 1 - Present data in graph or table so easier to compare data; useful to calculate standard deviation to see the spread of the data |
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Term
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Definition
| Increase in the value of one variable increases the value of the second variable |
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Term
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Definition
| Just becasue two variables have a positive correlation it does not mean they have a causal link; this could be down to many other factors, biotic and abiotic such as temperature |
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Term
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Definition
| Understanding of animal relationships with a commuinty help us to minimise human activities on the environment and conserve the communities. Collection of data may be harmful itself. |
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Term
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Definition
| Organisms must be studies In situ (in thier habitat) if they have to be removed, number should be kept to the minimum |
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Term
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Definition
| Organisms removed from a site must be returned to thier habitat ASAP. Even if they are dead, so predators can consume them for energy |
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Definition
| Sufficient time period before site is used again for future studies, so habitat can recover from disturbance |
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Term
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Definition
| Disturbance/damage should be avoided or kept to a minimum.. e.g trampling/ overturning stones at a beach, there is moisture under rocks and so overturning them will deprive organisms from water so they will die |
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Term
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Definition
| Balance between damage done and value of information gained. |
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Term
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Definition
| Stage 1 - LAG PHASE - Slow growth, few organisms are avaliable to breed. |
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Term
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Definition
| Stage 2 -LOG PHASE - Rapid growth, lots of organsims breeding rapidly; increasing number of individuals breeding rapidly. Population size doubles with each interval |
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Term
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Definition
| Stable growth - population can't grow any larger due to limiting factors. Population has reached it's carrying capacity. |
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Term
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Definition
- Mineral ions are used up as population grows
- Population becomes so large there is no space
- Other species are introduced to the habitat which may be predators or compete for resources
- Winter has lower temperatures and lower light intensity
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Term
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Definition
| Limiting factors slow population growth. Sometimes stop it completely so population diminishesd :( Ultimate size of populations depends on abiotic and biotic factors (the ones before and toxic waste and disease) |
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Term
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Definition
Temperature
Light
pH
Humidity
Salinity |
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Term
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Definition
| Each species has different optimum temperature - enzymes work more slowly at colder temperatures due to lack of kinetic energy so metabolic rate reduced; population growth slows.... too high a temperature, enzymes can be denatured so substrate can't bind to active site so they don't work |
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Term
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Definition
| Birds/mammals retain constant body temperature regardless of external temp. They can regualte thier body temp. however the further away the external temperature from body temp, the more energy is required to regulate the body temperature using up energy so less growth - population size shrinks |
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Definition
| Source of energy for ecosystems - light intensity increases rate of photosynthesis, so faster plant growth so more seeds produce, pop size and plant size increases with high light intensity. Therefore more food supplies for animals, so thier popluation grows too |
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Term
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Definition
| Effects enzyme action - Enzymes have optimum pH, this is the point at which they work best at. At other pH's they are denatured or shape of active site effected so no enzyme subtstrate complexes can form - can't function - large population at optimum pH of organisms and non existent / little population at different pH |
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Term
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Definition
| Low humidity - low water supplies - affect transpiration rates of plants and evaporation of water from animals: low water supply areas have small populations of only a few adapted species |
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Term
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Definition
| Biotic factor - 2 or more individuals share the same resource that is insufficient to satisfy all thier requirements |
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Term
INTRASPECIFIC COMPETITION |
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Definition
| Competition between members of the same species - avaliability of resources that determines size of population - greater avaliablity, larger population |
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Term
INTERSPECIFIC COMPETITION |
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Definition
| Competition between members of different species where populations of two species occupy the same niche - one normally has more competitve advantage than the other; this population increases whilst the other decreases |
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Term
COMPETITIVE EXCLUSION PRINCIPLE |
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Definition
| Two species are competing for limited resources, the one that uses thes resources most effectively will ultimately eliminate the other (no two species can occupy the same niche at the same time, so it 2 species do overlap niches, there will be competition) |
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Term
INCREASE IN FOOD SUPPLIES |
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Definition
| Doesn't necessarily mean increase in population this could just mean bigger individuals |
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Term
WHICH SPECIES HAS BIGGER COMPETITVE ADVANTAGE IN A NICHE?
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Definition
| Depends on whether one species is more adapted to certain conditions such as a higher pH or temperature - this species will then become dominant (however if temperature suddenly falls, the other species will be dominant |
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Term
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Definition
| Could decrease population - individuals may die of starvation and reduce population size. This means if food supplies are increased, more individuals will survive so more will reproduce increasing population. |
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Term
HOW TO SHOW A FACTOR INFLUENCES POPULATION SIZE |
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Definition
| Link factor to the birth rate and death rate of individuals in a population |
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Term
WHY IS IT DIFFICULT TO PROVE COMPETITION? |
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Definition
-Abiotic factors may also influence population size
-No causal link is established to show it is competition
-Time lag in competition so population change may be down to competition a few years back
-Data on natural habitats are hard to obtain and not always reliable |
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Term
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Definition
| Preadators feed on prey for energy |
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Term
EVOLVING OF PREDATORS AND PREY |
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Definition
| They have evolved together; if either of them did not evolve to the same standards of the other, it would have become extinct by now |
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Term
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Definition
| Predators are more adapted to capture prey - faster movement, effective camoulfage and detection. |
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Term
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Definition
| Prey are more adapted to avoid predators - better camouflage, more protective features (e.g spikes) secret/hidden/concealed behaviour |
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Term
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Definition
| With a population of a prey and a population of predator in a lab, the predator will win and exterminate the prey because they are not in thier natural habitat and the area is confined - this means the data collected is unrepresentative and not reliable |
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Term
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Definition
| Predators can rarely exterminate the prey population here; large area of which the prey can travel and a diverse environment so there are more places of refuge for the prey; population levels will fall at times, but rare extinction |
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Term
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Definition
Not all the members of a population can be counted - time consuming and disturbing to the population
- However samples only provide estimations of pop. size so not totally accurate |
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Term
PREDATOR - PREY RELATIONSHIPS |
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Definition
- Predators eat prey - reduce population of prey
- Fewer prey means predators in greater competition for food - predator population decreases
- Fewer predators means less prey eaten, prey population increases
- More prey means more food, predator pop. increases
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Term
HOW DO PREDATORS SURVIVE WITHOUT ANY PREY? |
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Definition
| Organisms eat a range of foods, so population of prey isn't that servere |
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Term
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Definition
| Survival of the fittest - There are cyclic fluctuations in population - not just down to predatation, also to diesease and climatic factors - only individuals that can survive these will be able to reproduce and pass down thier "good" genes |
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Term
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Definition
| Kept in check by disease, predators, and climate; recently it has increased massively due to developement in agriculture and the industrial revolution. Human population is increasing and war, disease and famine cause only temporary reversals |
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Term
LOG PHASE OF HUMAN POPULATIONS |
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Definition
| Exponential growth of the human population ,which means it grows rapidly, is continuing without any sign of giving way to the stationary phase |
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Term
FACTORS EFFECTING THE GROWTH AND SIZE OF HUMAN POPULATIONS |
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Definition
| Basic factors are birth rate and death rate. This determines whether the population changes or remains the same |
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Term
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Definition
Affected by immigration (individuals join a population) emmigration (individuals leave a population) Balance affects population size
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Term
FACTORS AFFECTING BIRTH RATES (1) |
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Definition
-Economic conditions - LEDC'S less contraception, higher birth rates
-Relgion/Cultures - Oppose birth control
-Social pressure - some countries need large families for social standing
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Term
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Definition
| Birth rate = (number of births per year / total population in same year) x 1000 |
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Term
FACTORS AFFECTING DEATH RATE (1) |
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Definition
-Age profile - larger proportion of elderly, larger death rate
-Life expectancy at birth - MEDC'S live longer
-Food supply - balanced diet reduces death rate
-Safe drinking water and sanitation - Reduces death rate by reducing water bourne diseases (cholrea)
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FACTORS AFFECTING DEATH RATE (2) |
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Definition
-Medical care - health care and education reduce death rate
-Natural disasters - positive correlation to death rate
-War - immediate killings - drop population and long term fall as less fertile adults |
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Term
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Definition
| Death rate = (number of deaths per year / total population in the same year) x 1000 |
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Term
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Definition
| From low life expectancy an high birth rate, to high life expectancy and low birth rate - this re-establishes the sigmoid curve - uncertain if it will happen in all countries |
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Term
AGE POPULATION PYRAMIDS
STABLE POPULATION |
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Definition
Birth rate and death
rate are in balance so
no decrease/increase in
population size |
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Term
AGE POPULATION PYRAMIDS (2)
INCREASING POPULATION |
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Definition
High birth rate so wide
base of population
pyramid. Fewer old
people so narrow point
to pyramid
e.g in LEDC'S |
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Term
AGE POPULATION PYRAMIDS (3)
DECREASING POPULATION |
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Definition
Lower birth rate
so narrow base
and lower mortality
rate so more elderly
people, therefore
wider point;
e.g. in MEDC'S |
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Term
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Definition
| The age at which 50% of the individuals of a population are still alive. This can be calculated using a survival curve |
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Term
FACTORS EFFECTING BIRTH RATE (2) |
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Definition
-Birth control - contraception and abortion
-Political factors - governement influence birth rate with tax and education |
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