Ecology and the Environment Flashcards
Define population, community, habitat, environment, ecosystem, and biodiversity
- Population: the number of living organisms of the same species living in the same place and time
- Community: different populations in a habitat
- Habitat: a place where living organisms live
- Environment: biotic and abiotic factors
- Ecosystem: interaction between organisms and their environment
- Biodiversity: the measure of the rage of species in an ecosystem
How is population size in a habitat (estimate) investigated?
- Select a quadrat of a suitable size (Ex: 1m²)
- The quadrat is placed randomly using random generator
- Count number of organisms in the quadrat
- Repeat and take average
- Calculate total estimated number of organisms in habitat
- a. This is done by multiplying the average by the total area
What are the effects of biotic and abiotic factors on the distribution of organisms?
Abiotic factors:
* Temperature
* Light intensity
* Wind speed
* Soil pH
Biotic factors:
* Competition over resources
* Availability of nutrition
* Predation (predators in ecosystem for species)
* Diseases
What processes are described in the energy flow in an ecosystem?
- Food chain: a diagram showing the flow of energy from one organism to the next beginning with a producer
1. Ex: Plant → Primary consumer → Secondary consumer - Food web: a network of interconnected food chains
Define producer, consumer, decomposer, herbivore, carnivore, and trophic level
- Producer: an organism that makes its own nutrients usually using energy from the sun (photosynthesis)
- Consumer: an organism that gets its energy by feeding
- Decomposer: an organism that gets its energy from decomposing dead or waste organic material
- Herbivore: an animal that gets its energy by eating plants
- Carnivore: an animal that gets its energy by eating animals
- Trophic level: the position of an organism in a food chain, food web, or a pyramid of biomass/numbers
State and explain the 3 types of ecological pyramids
Pyramid of numbers: shows the population of each trophic level
Pyramid of biomass: shows the biomass (mass) of each trophic level
Pyramid of energy: shows the energy transferred from one trophic level to the next
1. Only 10% is transferred between each trophic level
2. Energy is lost in the form of heat, and in the 8 life processes
What processes occur in the carbon cycle?
- Combustion: fossil fuels and plants can be burnt for fuel releasing carbon dioxide into the atmosphere
- Decomposition: bacteria/fungi convert complex molecules (waste/dead organic) into carbon dioxide
- Photosynthesis: takes in carbon dioxide, so less carbon dioxide in atmosphere
- Respiration: releases caarbon dioxide to the atmosphere
- Feeding: animals eat plants/other organisms
- Incomplete decomposition and fossilisation: leads to formation of fossil fules
What processes occur in the nitrogen cycle, and what organisms preform them?
- Nitrification: nitrifying bacteria oxidise the ammonia to nitrites, then to nitrates
- Denitrification: denitrifying bacteria: convert nitrates in the soil to nitrogen
- Nitrogen Fixation: nitrogen fixing bacteria convert nitrogen to ammonia
- Decomposers: produce ammonia from nitrogen in proteins in dead organisms
- Lightning: nitrogen fixation by nitrogen in air (Harber process)
What human influences affect the environment regarding pollution?
Pollution by sulfur dioxide:
* Sulfur dioxide reacts with water vapour to form acid rain
* Acid rain increases the acidity of lakes and soil, this leads to death of fish and plants
* Acid rain leads to erosion of buildings
* Inhalation of sulfur dioxide causes asthma and lung damage
Pollution by carbon monoxide:
* Reacts with haemoglobin in the blood to form carboxyhaemoglobin which decreases the concentration of oxygen in the blood
What are the greenhouse gases and how does the greenhouse gas effect work?
Greenhouse gases:
* Water vapour: naturally exists
* Carbon dioxide: burning fuels / In car exhausts
* Nitrous oxides: fertilizers / Cattle waste / At high temperatures in car engines
* Methane: released from cattle (livestock) / In rice paddy fields)
* CFCs: when fridges are disposed of (they are used in fridges) / Aerosol sprays
Greenhouse gas effect:
Greenhouse gases form a layer of impenetrable gasses that trap the Sun’s radiation in the Earth’s atmosphere causing global warming
What are the consequences of global warming?
- Habitat destruction
- Climate changes
- Migration of animals
- Extinction of animals
What are the causes of eutrophication and sewage pollution?
- Overuse of fertilizers
- Sewage disposal in water
What is the process of eutrophication?
- Leaching of mineral ions into rivers and lakes
- Overgrowing of algae (algal bloom) blocks sunlight
- Underwater plants don’t photosynthesise and die
- Increase in number of decomposers consuming O₂ in water causing death of fish
What is the relation between sewage pollution and eutrophication?
- Sewage contains microorganisms which will consume O₂ causing death of fish
- Sewage contains nutrients that will cause algal bloom
What are the effects of deforestation?
- Leaching
- Soil erosion as the roots of trees hold soil together
- Less transpiration, so less water vapour in air, so less rain
- Imbalance of CO₂ and O₂ in the atmosphere
- Destruction of habitats and extinction of animals
