What is an ecosystem
Ecosystem: All living things and their environment working together (like a forest or pond).
What is an organism
Organism: A single living thing (like a frog, bacteria, fungi or tree).
What is a habitat
Habitat: The place where an organism lives (like a pond for frogs).
What is a population vs a community
Population: A group of the same species living in one place (all the frogs in the pond).
Community: All different species living and interacting in the same area (frogs, fish, plants, insects in the pond).
What is biotic and abiotic
biotic (living) things
abiotic (non-living) things
What are Heterotrophs vs autotrophs
Autotrophs: Organisms that produce their own energy - plants (which means self-feeder)
Heterotrophs: Organisms that cannot photosynthesise (“other feeders”)
Describe some of the factors that may disrupt ecosystems: (natural impacts, human impacts and introduced species)
Natural impacts: Storms, fires, floods, or droughts
Human impacts: Humans COMPETE WITH OTHER ORGANISMS FOR RESOURCES. Things people do like cutting down trees, polluting, or building cities
Introduced species: Animals or plants brought in by humans that can take over and harm native species (like cane toads in Australia).
- Introduced species INCREASE COMPETITION for resources such as food, water and shelter. This can also lead to disruption of food webs.
Leaf structure:
Xylem: Transports water from the roots to the leaves
Phloem: Transports food from the leaves to the rest of the plant
Stoma: Allows carbon dioxide to enter and oxygen to be released from the leaf
Guard cells: Open and close the stomata
Palisade mesophyll: Contain a large amount of chloroplasts
Spongy mesophyll: Gaseous exchange
Describe how each part of the leaf structure and its function relate to photosynthesis
The xylem brings water to the leaves, and the phloem carries food to the rest of the plant. Stomata let carbon dioxide in and oxygen out, controlled by guard cells. The palisade mesophyll has many chloroplasts to absorb sunlight, while the spongy mesophyll allows gases to move through the leaf.
How are water and nutrients/sugar are transported in plants (xylem and phloem)
and whats the names of the processes?
Xylem: Carries water and minerals from roots → leaves. and the process is called transpiration.
Phloem: Carries sugars (glucose) made in leaves → rest of the plant. THe process is called transloaction
The process of Photosynthesis
(Where it happens, what is required, what conditions are needed, the products and the word equation)
Where: Chloroplasts in leaf cells
Required: CO₂, H₂O, sunlight
Conditions: Light, water, CO₂ available
Products: Glucose + O₂
Word Equation: Carbon dioxide + H₂O → (light + chlorphyll) → Glucose + Oxygen
Aerobic Respiration…
(requires…, where it occurs, produces more or less APT, when is it used and poducts)
- Requires oxygen
- Occurs in the mitochondria of cells
- Produces a lot of ATP per glucose molecule
- Used when heart rate and breathing rate rise
- Produces carbon dioxide and water as waste product
Anaerobic Respiration
(requires…, where it occurs, produces more or less APT, when is it used and poducts)
- Doesn’t require oxygen
- Occurs in the cytoplasm of cells
- Used during the first 1-2 minutes of exercise
- Produces less ATP per glucose molecule
- Produces lactic acid as waste product (in animals)
Understand the difference between the different variables.
(independent, dependant and controlled)
- Independent variable: what is changed by the experimenter
- Dependent variable: what is measured by the experimenter
- Controlled variables: all the factors kept the same/consistent in the experiment
What is a control
A control is a trial/set up in your experiment that does not contain the independent variable (what you are changing).
This allows you to determine the effect of your independent variable on what you are measuring (your dependent variable).
Whats the format for a hypothesis and what is the hypothesis
A hypothesis is an educated guess about what will be observed.
It is always written in the if… then… format.
What are the 2 types of scientific errors
Systematic and random errors
Whats a systematic error:
Affects the results in the same way and by the same amount every time. eg. Scales aren’t calibrated properly.
Whats a Random error:
Affects the results in different ways and by different amounts every time. e.g. the temperature fluctuates in the room while doing your experiment.
Whats accuracy vs precision
Accuracy = how close a measurement is to the true or accepted value.
Precision = how close measurements are to each other.
Whats an error vs a mistake.
Errors are NOT mistakes. They are anything that could potentially impact your results (no matter how slightly).
- Mistake: E.g: We spilled some of the solution, causing them to not be the same amount’
- Source of error: E.g:‘The measuring cylinder increased by 5mL increments, meaning the amounts had to be estimated’
What trophic levels does energy move through
producers → herbivores → carnivores
How much energy is lost/transferred as it moves through trophic levels?
10%
Energy moves up the trophic levels (producers → herbivores → carnivores).
Energy loss: At each level, about 90% of energy is lost as heat, movement, or waste. Only ~10% is passed to the next level.
Be able to describe the difference between a food chain and a food web?
Food chain: Shows a single line of who eats whom in an ecosystem.
Example: Grass → Rabbit → Fox
Food web: Shows many interconnected food chains in an ecosystem, giving a more realistic picture of feeding relationships.
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