Unit 1 Making a Living in the Wild Chapter 6 Foraging and migration

Foraging Ways to get food Use cost/benefit analysis Locating food 1. Straining- rare 2. Locating with the senses- most common Ex: bees use UV vision, hence coloration of flowers

coevolution Flowers and insects evolved together in mutual dependence When finding food, some choose safety over abundance of food Search image- as time goes on, ani gets better at finding its food

Food selection Animals will feed exclusively on their favorite food if it is abundant Some take more effort to find more nutritious food Generalists- omnivores Specialists- herbivores or carnivores Optimality models- most efficient food gatherer favored b/c least amt E wasted

Handling and consuming food Learn specific techniques 1. Animal cultivators- animals have relationships w/ plants or other animals Encourage the growth of plants or have a symbiotic relationship

2. Storing and caching- instead of eating food immediately, they may save it for later Dig holes, hide in crevices, etc Must use senses/memory to find the food again

Migration Periodic journey to a specific location that alternates with a return journey to the place of origin Cost/benefits Many die each year during migration Ending location better for lifetime fitness Ex: mating, food, less predators Breeding area vs. rest of year survival area

Migration in birds Half of all bird species migrate Banding used to track Internal biological clocks set by external seasonal stimulus Photo period- length of time sun is out per day Hormones tell the bird to migrate

Circadian rhythm 24 hour cycle in the physiological process of beings Including plants and animals Can be affected by light and dark cycle changes Determines sleeping and feeding patterns Biological activities linked such as temp, brain wave activity, hormones, etc

Navigation in birds Cues from environment and ability to use them Map sense- knowledge of current location relative to goal Compass sense- knowledge about direction Piloting- using landmarks

Sun compass- use sun’s position to navigate Star position migration at night, use more fixed stars such as Polaris, learn patterns of stars, when cloudy the mvt is random

Geomagnetic cues- not use sun or stars use earth’s magnetic field instead organ inside brain that contains magnetic granules

Migration in mammals Less number than birds Most mammals hibernate instead Large herd mammals migrate, mostly hoofed (ungulates) Not usually small mammals Tracked using radio transmitter