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Definition
| All the biotic and abiotic features in a specific area. They are more or less self contained functional units. |
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Definition
| A group of interbreeding organisms of one species in a habitat. |
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Definition
| 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 community of organisms lives. |
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Term
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Definition
| How an organism fits into the environment. Where an organism lives and what it does there. |
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Term
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Definition
Consider:
>The size of the quadrat to use
>The number of sample quadrats to record within the study area
>The position of each quadrat within the study area |
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Term
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Definition
1. Lay out two long tape measures at right angles, along two sides of the study area
2. Obtain a series of coordinates by using random numbers taken from a table or generated by a computer
3. Place a quadrat at the intersection of each pair of coordinates and record the species within it |
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Term
| 1.2 Measures of Abundance - Frequency |
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Definition
| The liklihood of a particular species occuring in a quadrat. This is useful where a species, such as grass, is hard to count |
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Term
| 1.2 Measures of Abundance - Percentage cover |
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Definition
| An estimate of the area within a quadrat that a particular plant species covers. It is useful where a species is particularly abundant or is difficult to count. |
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Term
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Definition
| This is important where some form of transition in the connunities of plants and animals takes place. |
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Term
| 1.2 Systematic Sampling - Line Transect |
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Definition
| Using a line transect, which compromises of a string stretched across the ground in a straight line. Any organism over which the line passes is recorded. |
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Term
| 1.2 Systematic Sampling - Belt Transect |
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Definition
| A strip, usually a metre wide, marked by putting a second line parallel to the first. The species occuring within the belt between the lines are recorded. |
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Term
| 1.2 Estimated Population Size |
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Definition
| = Total number of individuals in the first sample X total number of individuas in the second sample / number of marked individuals recaptured |
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Term
| 1.2 Assumptions of Mark, Release, Recapture |
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Definition
>The proportion of marked to unmarked individuals in the second sample is the same as the proportion of marked to unmarked individuals in the population as a whole
>The marked individuals released from the first sample distribute themselves evenly amongst the remainder of the population and have sufficient time to do so
>The populations has a definite boundary so the is no immigration or emmigration
>There are few, if any, deaths and births
>The method of marking is not toxic to the individual nor does it make the individual more conspicous and more liable to predation
>The mark or label is not lost or rubbed off during the investigation |
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Term
| 1.3 Population Growth Gurves |
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Definition
1. A period of slow growth as the initially small number of individuals reproduce slowly to build up their numbers
2. A period of rapid growth where the increasing number of individuals continue to reproduce
3. A period when the population growth declines until its size remains more or less stable. The decline may be due to the food supply limiting number or predation. |
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Term
| 1.3 Abiotic Factors that Affect Population Sizes - Temperature |
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Definition
| Each species has a different optimum temperature at which is it best able to survive. The further away from this optimum, the smaller the population that can be supported. As the temperature falls below the optiumum the enzymes work more slowly and so their metabolic rate is reduced. Populations therfore grow more slowly. At temperatures above the optimum, the enzymes work less efficiently because they gradually become denatured so the population grows more slowly. |
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Term
| 1.3 Abiotic Factors that Affect Population Sizes - Light |
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Definition
| The rate of photosynthesis increases as light intensity increases. The greater the rate of photosynthesis, the faster the plants grow and the more seeds the produce. Their population growth and size is therefore potentially greater. |
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Term
| 1.3 Abiotic Factors that Affect Population Sizes- pH |
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Definition
| This affects the action of enzymes. Each enzyme has an optimum pH which it operates more effectively. A population of organisms is larger where the appropriate pH exists and is smaller, or non-existant, where the pH is very different from the optimum. |
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Term
| 1.3 Abiotic Factors that Affect Population Sizes - Water and Humidity |
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Definition
| Where water is scarce, populations are small and consist only of species that are well adapted to living in dry conditions. Humidity affects the transpirations rates in plants and the evaporations of water from animals. In dry conditions, the populations of species adapted to tolerate low humidity will be larger than those with no such adaptions. |
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Term
| 1.4 Intraspecific Competition |
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Definition
| Individuals of the same species compete with one another for resources such as food, water, breeding sites, etc. |
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Term
| 1.4 Intraspecific Competition - Limpets |
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Definition
| Limpet compete for algae, which is their main food source. The more algae available, the larger that limept population becomes. |
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Term
| 1.4 Intraspecific Competition - Oak Trees |
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Definition
| Oak trees compete for resources. In a large population of small oak trees some will grow larger and restrict the availability of light, water and minerals to the rest, which then die. In time the populations will be reduced to relatively few larger dominant oaks. |
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Term
| 1.4 Intraspecific competition - Robins |
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Definition
| Robins compete for breeding territory. Female birds are attracted to males with the biggest breeding area as each territory provides adequate food for a family of birds. If food becomes scarce territories have to become larger so there are less breeding pairs, leading to a smaller population size. |
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Term
| 1.4 Interspecific Competition |
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Definition
| Individuals of different species compete for resourfces such as food, light, water, etc. |
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Term
| 1.4 Competivite Exclusion Principle |
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Definition
| Where populations of two species occupy the same niche, one will normally have the advantage over the other. The populations of this species will gradually gain in size while the other will diminish. If conditions remain the same, it could lead to the complete removal of one species. |
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Term
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Definition
| Predation occurs when one organism is consumed by another. |
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Term
| 1.5 Effect of Predator-Prey Relationship on Population Size |
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Definition
>Predators eat their prey, reducing the population of the prey
>With fewer prey available the predators are in greater competition with each other for the remaining prey
>The predator population is reduced as some individuals are unable to obtain enough prey to survive
>With fewer predators left, fewer prey are eaten
>The prey population therefore increases
>With more prey available, the predator population increases |
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Term
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Definition
Two major events have led to an explosion of the human population:
>The development of agriculture
>The development of manufacturing and trade that created the industrial evolution |
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Term
| 1.6 Factors Affecting the Human Population |
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Definition
>Birth rates
>Death rates
>Immigration
>Emmigration |
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Term
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Definition
| = (births + immigration) - (deaths + emmigration) |
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Term
| 1.6 Percentage Population Growth Rate |
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Definition
| = population change during the period / population at the start of the period X 100 |
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Term
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Definition
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Term
| 1.6 Factors Affecting Birth Rates |
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Definition
>Economic conditions
>Cultural and religious backgrounds
>Social pressures and conditions
>Birth control
>Political factors |
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Term
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Definition
| = number of births per year / total populations in the same year X 1000 |
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Term
| 1.6 Factors Affecting Death Rates |
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Definition
>Age profile
>Life expectancy at birth
>Food supply
>Safe drinking water availability
>Effective sanitation
>Medical care
>Natural disasters
>War |
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Term
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Definition
| = number of deaths per year / total populations in the same year X 1000 |
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Term
| 1.6 Demographic Transition |
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Definition
| In most economically well-developed nations, such as those of North American and Europe, there has been a large increase in life expectancy. This has led to c change in societies, from those where list expectancy is short and birth rates are high, to those where life expectancies and high and birth rates are low. |
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Term
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Definition
| The birth rate and death rate are in balance and so there is no increase or decrease in the population size |
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Term
| 1.6 Increasing Population |
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Definition
| There is a high birth rate, giving a wider base to the population pyramid and fewer old people, giving a narrower apex to the pyramid. This population is typical of economically less developed countries. |
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Term
| 1.6 Decreasing Population |
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Definition
| There is a lower birth rate and a lower mortality rate leading to more elderly people. This type of population occurs in certain economically more developed countries such as Japan. |
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Term
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Definition
| ATP + H2O -> ADP + Pi + Energy |
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Term
| 2.1 Condensation Reaction |
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Definition
| A chemical process in which 2 molecules combine to form a more complex one with the elimination of a simple substance, usually water. |
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Term
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Definition
| The breaking down of large molecules into smaller ones by the addition of water molecules. |
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