B3 LIFE ON EARTHLesson 1: Species and Adaptation

OBJECTIVESMUST explain how species are adapted to their environments and give examples

SHOULD explain that species compete for resources

COULD predict the effect on species of disturbance to a food web

KEY WORDS You need to be able to define the following:

Adaptation Species Habitat Competition Food web Interdependence

TEXTBOOK ANSWERS1) A group of organisms that can breed together to

produce fertile offspring.2) It has gills for gaseous exchange; these can

exchange gases across their surface underwater; it has fins to keep it upright when swimming; it has a mouth position that suits its way of feeding; a swim bladder that allows it to maintain a variety of depths in the water.

3) Space (particularly space in the light spots where there is a gap in the canopy above); light; nutrients (the competition for nutrients would be between their root systems).

TEXTBOOK ANSWERS4) There might be more heather for the sheep and

rabbits to feed on, but the populations of shrews and lizards would decrease. The population of insect-eating birds would decrease because their food source has gone; the population of owls and merlins might also be impacted because one of their groups of prey species (the insect-eating birds) was depleted.

6) The way that all the species in the habitat depend on one another for survival; if the number of one species dropped or increased rapidly, this would have a knock-on effect on all other species in the food web (with examples).

WORKSHEET ANSWERSActivity 1 (Low demand) Polar bear: In order – cold, thick fur, insulate, blubber,

black, snow, claws, nostrils Water lily: In order – supported, surface, waxy cuticle,

absorb sunlight, wind, water movement,