Ecology - Triple only Flashcards
State the three environmental factors that can cause a change in the distribution of organisms.
Water availability, temperature, (dissolved) atompsheric gases concentration
Give three possible reasons to changes in environmental factors.
Seasonal changes, geographical changes, result of human interaction
Suggest one positive change on the environment due to human interaction.
Maintain rainforests / Reduce water pollution and monitor pH / Restrict entry to protected areas / Conservation measures
Suggest one negative impact on the environment due to human interaction.
Global warming and climate change / Acid rain / Pollution
Suggest how organisms may adapt to seasonal changes.
Migrate to areas with more ideal conditions
Define ‘trophic level’.
Position of organisms within a food chain
What kinds of organisms are in trophic levels 1 and 4 respectively?
1: Producers; 4: Tertiary consumers
State the name given to carnivores with no predators above their level.
Apex predators
How do decomposers break down organic matter?
Secrete enzymes into the environment –> absorb small soluble food molecules back in through diffusion
What needs to be done to an organism in order to measure its biomass?
Kill it + dry them out
What is a problem with measuring wet biomass?
Water levels vary throughout the day and dependent on conditions –> less repeatable results
State the original source of all biomass.
Photosynthesis
Which trophic level is always at the bottom of the pryamid of biomass?
Trophic level 1 (producers)
What happens to the amount of biomass at each trophic level as we go up the food chain?
Decreases
Give three reasons why biomass always decreases as we go up the trophic levels.
- Not whole/part of organisms are eaten; 2. Some biomass taken in is passed out and lost as waste; 3. Most biomass taken in is used up in respiration, only some used to build new biomass
What is incident energy?
All the energy from the sunlight falling on Earth
Approximately how many percent of the incident energy is used by producers to do photosynthesis?
1%
Approximately how many percent of the biomass from each trophic level is transferred to the next?
10%