Competition

WHEN RESOURCES ARE INSUFFICIENT TO SATISFY ALL INDIVIDUALS FULLY

INTRASPECIFIC - SAME SPECIES

 AVAILABILITY OF RESOURCES DETERMINES POPULATION SIZE. E.G LIMPETS FOR ALGAE, OAK TREES COMPETETING, LARGER ONES RETSRICT LIHT FOR SMALLER ONES WHICH DIE

INTERSPECIFIC - DIFFERENT SPECIES

 WHEN POPS OF TWO SPECIES OCCUPY SAME NICHE, ONE WILL HAVE COMPETITIVE ADVANTAGE

COMPETITIVE EXCLUSION PRINCIPLE - COMPETITIVE ADVANTAGE SPECIES INCREASE IN SIZE WHILE OTHER SPECIES POP DIMINSIHES, IF CONDITIONS REMAIN SAME, COMPLETE REMOVAL OF ONE SPECIES

COMPETITIVE EXCLUSION PRINCIPLE - WHEN 2 SPECIES ARE COMPETING FOR LIMITED RESOURCES, ONE THAT USES THESE RESOURCES MOST EFFECTIVELY WILL ULTIMATELY ELIMINATE THE OTHER. NO TWO SPECIES CAN OCCUPY SAME NICHE WHEN RESOURCES ARE LIMITING

TO SHOW HOW FACTOR INFLUENCES SIZE OF POPULATION, NECESSARY TO LINK TO BIRTH AND DEATH RATE. E.G MORE FOOD DOES NOT NECESSARILY MEAN MORE INDIVIDUALS, MIGHT JUST MEAN BIGGER ONES. HOWEVER COULD MEAN MORE LIKELY TO SURVIVE AND INCREASED PROBABILITY TO PRODUCE OFFSPRING

WHY COMPETITION MAY NOT BE FACTOR OF POPULATION

• MANY OTHER FACTORS E.G ABIOTIC
• CAUSAL LINK MUST BE ESTABLISHED TO SHOW COMPETITION CAUSE OF OBSERVED CORRELATION
• TIME LAG IN COMPETITION, POPULATION CHANGE MAY BE DUE TO COMPETITION FROM YEARS EARLIER
• DATA ON POP. SIZES HARD TO OBTAIN, NOT ALWAYS RELIABLE