"Competition, why yes I would love some"

Habitat - The place where an organism lives, e.g. A rocky shore or a field.

Population - All the organisms of one species in a habitat. 

Population Size - The number of individuals of one species in a particular area. 

Community - Populations of a different species in a habitat make up a community. 

Abiotic Factors - The non-living features of the ecosystem, e.g. temperature and availability of water. 

Biotic Factors - The living features of the ecosystem e.g. the presence of predators or food. 

Abundance - The number of individuals of one species in a particular area. (It's the same as population size!)

Distribution - Where a species is within a particular area. 

Population size of a species is affected by abiotic factors, e.g. the amount of light, water or space available, the temperature of the surroundings and chemical composition of their surroundings. 

Abiotic conditions are ideal for a species when organisms can grow fast and reproduce successfully. For example when temperature is ideal animals do not have to use up much energy to maintain their body temperature. This means more energy can be used for growth and reproduction resulting in a population INCREASE! 

Abiotic conditions are not ideal for a species when organisms can't grow as fast or reproduce as successfully. For example if temperature or too high or too low meaning they have to use more energy to maintain the right body temperature. This means there is less energy available for growth and reproduction resulting in a population DECREASE!