1. Animal and plant responses Homing and Migration (CB pg 216 – 222)

2. HOMING Ability of an organism to return to the home site after it has been away sometimes over considerable distances. e.g. social insects bees  hive ants  nest termites  mound rabbits  burrow

3. Cataglyphis ants live in the desert and go out to look for food during the hottest part of the day (It gets up to 50 o C). They search (Route A) for food and when they find it they will track their way directly back to the nest (Route B). D Route A Route B Food Nest The dots on route A and B indicate where the ant stops and spins around slowly.

4. Contrast the method used by Cataglyphis for finding its food to that of returning to it’s nest. Give the benefits of both behaviours. HAVE A GO AT ANSWERING THIS ON YOUR OWN Achievement: Describes the random searching movement in route A and the direct route of return route B Merit: Achieved plus explains the movements. A – to cover terrain in search of food is random to cover more ground and discover sources of food B – is direct home after food is found to save time and energy in the direct heat/sun and get food back to nest. Excellence: Merit and discusses orientation movement. Ants use the sun as positioning/orientation on route A to find food and this allows more direct route to home with fewer turns to orientate on return route B vs on outward trip A

5. MIGRATION Regular, annual or seasonal mass movements made by animals from their breeding area to another area TASK: Complete a t-chart that shows the advantages and disadvantages of migration

6. AdvantagesDisadvantages Animals remain in favourable temperature (reduces energy expenditure of having to stay warm) Grow larger (salmon that don’t migrate grow to 20cm, those that do grow to 100cm) Leave more offspring (in salmon up to 125 x more) Have constant food supply May lead to colonisation of new area Reduces predation/parasitism/ disease Greater genetic mixing Better breeding conditions May get lost or caught in storm May get eaten by a predator May use up too much energy in the migration, leading to exhaustion They may starve Huge investment in energy

7. Triggers to migration Maturation as sex organs mature Environmental cues e.g. drop in temperature, shortening of day length  Triggers zugunruhe (migratory restlessness in birds) Genetic drive (built in/innate) Endogenous circannual rhythm

8. METHODS OF HOMING AND MIGRATION Piloting – moving from one familiar landmark to another (visual clues). Short distances only Compass orientation – travelling in a straight line using magnetic field lines, chemical clues and sound True Navigation – requires a map sense (latitude and longitude) and a sense of timing (internal clock) Both of these are needed for solar (sun) and stellar (star) navigation.

9. METHODS USED FOR MIGRATION OR HOMING 1.Visual clues 2.Solar navigation 3.Magnetic fields 4.Star (stellar) navigatipn 5.Chemical navigation 6.Sound used as sonar

10. Visual clues Birds – learn shape of coastline Other animals – learn where streams and food trees lie

11. Digger wasp Explain how the wasp finds its way when returning to its burrow from a hunting expedition The following figure shows the results of an experiment carried out to study homing behaviour in a hunting wasp. The wasp digs a burrow and then flies off to capture a caterpillar, which it will leave in the burrow as food for its young (2006). 1.Pine cones placed round burrow while wasp inside: wasp leaves and returns to nest 2.Pine cones moved while wasp away on hunting trip

12. Gray whales

14. Solar navigation Sun moves from east to west during the day so can be used to tell direction if you have a clock Birds and honeybees use the sun as a compass which suggests they have an inbuilt clock

15. Large migratory birds Birds that fly during the daytime are thought to use the sun as a compass They compensate for changing direction of the sun. In autumn in NH bird flies S at an angle of 45 to the left of the sun at 9am and 45 to the right of the sun at 3pm

17. Honey bees Round dance – used when nectar is within 50m of the hive. Waggle dance – indicates distance and direction Slow and few waggles on the straight – flowers far away Fast and rapid waggles – closer Direction is then determined from the direction of the straight to the sun

18. Honey bees

20. Stars as a compass Birds use star patterns for migration Important factor is the South Celestial Pole in the Southern Hemisphere – it doesn’t move

22. South

23. Magnetic field as a compass Many animals can detect the earth’s magnetic field (birds, bees, mice, some fish) Often used to supplement other compasses Can be used to determine latitude as the magnetic field is horizontal at the equator and vertical at the poles Different areas have different field strengths, animals may build up a map of strengths in areas

24. Magnetic fields Thought to be used by homing pigeons Involves following of magnetic field lines of the earth i.e. have magnetic compass If a magnet deflecting the normal magnetic field is attached to the head of a homing pigeon, the bird can be made to fly off course. On clear days, however, the birds use the sun and visual landmarks and still manage to get home Whales, dolphins and bacteria are all known to have magnetic compasses