living world Flashcards
what is an ecosystem
a natural system made up of plants animals and the environment interlinked, biotic and abiotic
what is biotic
living
what is abiotic
non living - temperature, water, light intensity, soil pH
example of small scale ecosystem
pond, hedgerow, woodland
fresh water pond
provides a variety of habitats for plants, animals, birds and insects
abiotic factors - light, water, oxygen availability
grasses, flowering plants, willow trees grow on damp ground around the pond, reeds grow in water at edges
pond bottom - little O2 or light, lots of shelter
decomposers and scavengers live here
what is a producer
convert energy from sun into food (sugars)
usually plants who convert energy from sun via photosynthesis
what are consumers
get energy from producers/ the consumers below them - snail who eats plants
what are decomposers
break down plant and animal material and return nutrients to soil
bacteria, fungi
what is a food chain
shows the direct links between producers and consumers in a simple line
what is a food web
shows interrelationships between producers and consumers in a more complex way
what is nutrient cycling
nutrients are foods that are used by plants or animals to grow
when plants animals die the decomposers help to recycle the nutrients making them available once again for the growth of plants and animals
species in fresh water pond
frog tadpole
algae - energy from sunlight
sticklebacks
heron
perch - energy from small fish (sticklebacks) beetles, water fleas
what causes change to ecosystems
changes to an ecosystem can occur naturally or result from human activities
globally - climate change
locally - changes to habitats like when a hedge is removed
natural changes to an ecosystem
ecosystems can adapt to slow natural changes
rapid changes have impacts like droughts - plants will dry out and die, fish starve of oxygen and die
human changes to an ecosystem
agricultural fertilisers - lead to eutrophication, nitrates increase growth of algae, deplete oxygen, fish die
ponds drained for farming - aquatic plants die, fish and other pond life die
woods cut down - destroy bird habitats, effects nutrient cycling
hedgerows removed - habitats destroyed, alters plant/animal balance
many farmers using less fertiliser, planting hedgerows, grass margins
global ecosystems
or biomes
defined mainly by type of vegetation in the area and the weather
polar ecosystem
located in arctic/antarctic
very low temperatures, dry conditions, mainy greenland and antarctica where temp can fall below -50 degrees C
deciduous and coniferous forests
located 50-60 degrees north of the equator
deciduous shed leaves in winter to retain moisture
coniferous treesare evergreen to maximise photosynthesis during brief summer period
temperate grassland
roughly 30-40 degrees north and south of equator, in land
hot summers, cold winters, mainly for grazing animals
mediterranean
roughly 40-45 degrees north of equator
hot sunny dry summers, mild winters
tropical grassland (savanna)
between 15-30 degrees north and south of the equator
tropical climate, distinct wet and dry seasons
tundra
from arctic circle to about 60-70 degrees north
low-growing plants adapted to retain heat in cold windy and dry conditions
fragile, easily damaged