Ecosystems Flashcards
What is an ecosystem?
A community of organisms (species) interacting in a given environment. This includes abiotic and biotic factors of the habitat.
Give examples of micro-habitats
(small)
- tree stump
- aquarium
Give examples of macro-habitats
(large)
- caribbean oceans
- african planes
Name the characteristics of living things
- They are made out of cells
- They acquire and use energy (nutrients)
- They grow and develop (mitosis)
- They reproduce
- They respond and adopt to their environment (within reason)
What are trophic relationships often represented by?
A food chain
How many trophic levels are there?
3
What are the trophic levels?
Producers
Consumers
Decomposers
Food chains are the representation of what?
The trophic relationships between different living things
What are food webs?
A group of interrelated food chains
In food webs/chains, arrows point to what
The direction of energy flow (things point to what they get eaten by)
What is transformed/transferred in a food chain? What is this called?
Matter and energy
Energy flow
All of the organic matter in an ecosystem is known as what?
Biomass
What is biomass?
All of the organic matter in an ecosystem
Flow of matter and energy can be represented by what?
Ecological pyramids, food webs and food chains
Describe how ecological pyramids represent the flow of matter and energy
Each trophic level is represented by a rectangle whose size is proportional to the amount of biomass it has
Biomass represents what? Unit?
The total number of mass living in an ecosystem at any given time (kg)
What happens to the amount of energy and biomass as it goes up a trophic level?
Both energy and biomass usually decrease by a factor of 10 with each trophic level since organisms give off energy to breathe, eat, reproduce, move, etc.
Trophic levels affect what? Why?
Relative abundance and population size for the whole ecosystem to remain in balance
How much energy is transferred when going up a trophic level in a pyramid? How much is wasted?
10%transferred
90%wasted
Is a rainforest or tundra more productive? Why?
Rainforest
Its biome supports more abundance and diversity
Describe producers.
- They are autotrophs, so they produce their own food
- They convert inorganic material (H20, CO2) into organic material (protein, sugar)
- A principal mechanism includes the production of sugar by photosyntesis
6CO2 + 6H2O + energy -> C6H1206 + 6O2
Give examples of producers
- Algae
- Plants
- Cyanobacteria (blue-green algae): They were the first unicellular organism to produce O2 in Earth’s history
What is primary productivity?
The total quantity of new organic material made by the producers in an ecosystem over a certain period
Primary productivity depends on what factors (examples)
- Sun light
- Carbon dioxide concentration
- Availability of nutrients
- Water
- Temperature
Plants and algae produce the most O2 at what temperature?
20 - 25C
Primary productivity is highest in what areas? Why?
Costa Rica/Borneo
Because they are warm and humid
Describe consumers
- They are heterotrophs because they get their food from a variety of other living things
1. Primary consumers (herbivores): feed on leaves and fruit or their seeds
2. Secondary and tertiary consumers (carnivores): feed on animals on the level below them (tertiary is highest, then secondary, then primary)
Omnivores: consumers of multiple orders (levels) at once
Describe decomposers
- They feed on dead and/or remains of producers and consumers
- This connects them to all the trophic levels
Describe chemical recycling
- Occurs when decomposers make inorganic matter available in an ecosystem by breaking down organic matter
- At each tropic level in a food chain a certain amount of material is recycled by decomposers back into nutrients that producers can use
Ecosystem dynamics respect what?
The law of conservation of energy
nothing can be created or destroyed, matter can only be transformed
Who invented the law of conservation of mass?
Antoine Laurent de Lavoisier
What is an ecological disturbance?
An event that destroys/harms an ecosystem. It can lead to the elimination of organisms (extinction) and change the availability of resources
Name and describe the types of disturbances
- Natural disturbances: occur due to environmental phenomena such as mudslides/floods
- Human disturbances: the main form of ecological disturbance on Earth
What is ecological succession?
The series of changes that occur over time in an ecosystem after a disturbance and that continue until the balance of the ecosystem is restored
How long does it take for a forest to regrow after a fire which destroys it?
150+ years
What are ecological footprints?
The estimate of how much available resources we consume and how much waste we generate
How is ecological footprint calculated?
Ecological footprint = Land + water occupied
+ land and water used to produce goods & services for a population
+ land and water used to dispose of our waste
What does HPI stand for?
Happy Planet Index
How is HPI calculated?
HPI= Experienced well-being x life expectancy
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Ecological footprint
