Obtaining food in Animals 24

Obtaining food in animals : 

Obtaining food in animals

Foraging behaviour : 

Foraging behaviour FORAGING: is the way in which animals search for food involving patterns of movement. Animals are HETROTROPHIC which means they rely on other organisms for food. Search Patterns: increase the chance of locating food can vary as changes in food availability occur depend on the type of food being preyed upon If food is present the planaria moves down the concentration gradient as a the chemical are picked up by the chemoreceptor's If food is absent the planaria moves randomly to increase area covered. Increases chances of finding food.

Symbiotic Animals : 

Symbiotic Animals SYMBIOTIC ANIMALS are different species that live in a close feeding relationship with each other. PARISITISM- host suffers, parasite gains. e.g. Hook worm feeding on intestinal gut 2. COMMENSALISM- Host unaffected, communal gains. e.g. Pilot fish with shark 3. MUTUALISM- both species benefit. e.g. Cattle egret eating the insects disturbed by the buffalo

Economics of Foraging : 

Economics of Foraging For foraging to be economically positive: ENERGY GAIN > ENERGY USED NET GAIN (ALIVE) Energy Expenditure: Search energy high, catch energy low- animal is non- selective which reduces energy expended on further searching. Search energy low, catch energy high- animal is selective to reduce energy expended in further pursuit.

Economics of forgingRichness of food supply : 

Economics of forgingRichness of food supply Scarce Energy cost in finding food is high. Must be non- selective in choice of food. Maximises energy gain. Abundant Energy cost in finding food is low Selects best food Maximises energy gain

Economics of ForagingChoice of prey size : 

Economics of ForagingChoice of prey size Medium is the optimum size of prey as it is relatively easy to catch and relatively high in energy.

Competition : 

Competition Competition occurs when resources are scarce. There are two types of competition: INTERSPECIFIC between individual of different species competing for similar resources losing species will migrate or face extinction INTRASPECIFIC between individuals of the same species competing for identical resources population size is regulated

Dominance Hierarchy : 

Dominance Hierarchy In social groups of animals a DOMINANACE and SUBORDINATE status results due to the aggressive behaviour towards others. Advantages: reduces conflict reduces energy expended in competition ensures ‘fittest’ individuals pass on genes Dominance behaviour Subordinate behaviour

Co-operative hunting : 

Co-operative hunting CO-OPERATIVE hunting is when animals within the same social group work together to catch and share the same food. ADVANTAGES: The group can catch animals that solitarily could not The chances of catching the prey are increased even the weaker individuals catch prey. http://www.dailymotion.com/video/x54wyj_wolf-hunting-tactics_animals