Topic 4: Ecology Flashcards
State one greenhouse gas. [1]
Carbon dioxide/methane/nitrogen oxides/water vapour/ozone/CFCs
Explain how radiation of different wavelengths is involved in the greenhouse effect. [2]
- incoming short-wave radiation (UV) passes through the earth’s atmosphere
- converted to long-wave radiation (infrared)
- atmosphere traps infrared
Outline two consequences of a global temperature rise on arctic ecosystems. [2]
- loss of ice habitat
- risk in sea levels
- changes in the distribution of prey species, affecting higher trophic levels
- increased rates of decomposition
Outline one effect of a temperature rise on plants. [1]
- rate of photosynthesis increases
- rate of transpiration increases
Define habitat, population, community and ecosystem. [4]
Habitat: the environment in which a species normally lives
Population: a group of organisms of the same species living in an area at one time
Community: multiple populations of different species living and interacting in the same area
Ecosystem: a community and its interactions with abiotic parts of its environment
Outline how energy flows through an ecosystem. [6]
- producers convert light energy into chemical energy (photosynthesis)
- such as organic compounds
- energy moves up trophic levels
- 10% of energy passed along the food chain
- energy lost in the form of heat
- lost by respiration
- lost as not digested/in faeces
- lost through death of organisms
- passed to decomposers
- energy not recycled
Describe what is meant by a food chain and a food web. [6]
Food Chain
- shows the transfer of nutrients/energy in an ecosystem
- between different trophic levels
- starting with a producer;
- followed by at least two levels of consumers
Food Web
- interaction of multiple food chains
- using (multiple) producers as a source;
- transferring nutrients/energy to consumers from different food chains;
- the same consumer could be at different trophic levels in a food web
Explain the relationship between rises in the concentration of atmospheric gases and the enhanced greenhouse effect. [8]
- water vapour;
- carbon dioxide;
- methane;
- oxides of nitrogen;
- all (of these gases) occur naturally;
- human activity has increased the normal level of greenhouse gases;
- incoming short-wave radiation (UV) from the Sun;
- is re-radiated as long-wave radiation (infrared);
- (mainly) in the form of heat;
- captured by greenhouse gases;
- increases the atmospheric/ocean temperature;
- at a higher rate than normal;
- threatens ecosystems/climatic patterns/ocean patterns;
Explain the processes by which energy enters and flows through ecosystems. [8]
- light energy (from Sun) initial energy source
- producers convert light energy to chemical energy
- produce organic compounds (sugars/carbohydrates)
- used for energy/growth/storage
- energy passes as food along trophic levels
- respiration releases energy as ATP from food
- energy lost as heat
- 10% energy passed to the next trophic level
- energy lost in undigested food/faeces
- passed to decomposers (remove energy from wastes)
- energy not recycled
Producers extract phosphates and nitrates from soil. Outline how these ions are used in the synthesis of organic molecules. [3]
- by photosynthesis / using energy from light
- attached to carbon compounds
- phosphates used to make phospholipids/nucleotides/nucleic acids/DNA/RNA/ATP
- nitrates are used to make amino acids/proteins/nucleotides/nucleic acids/DNA/RNA/ATP
Predict how global warming may threaten the survival of such an ocean bird. [1]
- global warming causes rising ocean levels, destroying breeding sites / drown baby birds
- populations cannot find new colony sites
- warming seas affect the food supply
Outline the energy flow through this food web. [3]
- light energy from the Sun is converted into chemical energy by autotrophs
- detritivores/saprotrophs decay plant material
- consumers release energy from carbon compounds by cell respiration, energy is lost as heat
- energy used for metabolism
- energy transferred between trophic levels
- 90% of energy lost between trophic levels
Describe what is meant by a food chain. [2]
- food chain shows feeding/trophic relationships
- shows which organisms eats which organism
- shows flow of energy from autotroph to top consumer through trophic levels
State one reason that the population of mountain lions is smaller than the populations of other animals in the food web. [1]
mountain lions are at the highest trophic level, receive the least energy as energy is lost between trophic levels
Aquatic and other environments are being affected by a global rise in temperature. Outline the consequences of this on arctic ecosystems. [6]
- loss of ice habitats
- raises sea levels
- decrease in size of populations
- arctic species move/adapt
- change in the distribution of species
- affects food webs/chains
- increased rates of decomposition of detritus
- increased success of pest species including pathogens
