Chapter 12. Interactions within ecosystems Flashcards
Wasting food
Growing crops and livestock requires resources such as:
- Water, energy, minerals in the soils
Wasting food means wasting the earth’s limited resources
Using more electricity
Electrical energy in Singapore is obtained by burning natural gas:
- Limited resource and can run out
- More electricity used, more fuels burnt to generate electricity
- More carbon dioxide given off contributes to climate change
Using more water
-Less than 1% of water covering the earth is fresh water
- Fresh water is limited resource.
- Consumption of water increases, fresh water depletes quicker
Creating excessive waste
- When excessive was is produced, more waste needs to be disposed
- Improper disposal of waste products like air, water and land (e.g. waste that is disposed in oceans can poison or kill marine organisms which consume it)
Ways to conserve environment
- Reduce use of fossil fuels
- Use energy - efficient appliances
- Reduce consumption
- Introduce environmentally friendly practices
- Reforestation
Reduce use of fossil fuels
Take public transport, walk or cycle instead of taking private cars
Use energy-efficient appliances
Help to reduce the use of fossil fuels to power cars and electrical appliances
Reduce consumption
- Reduce use of paper, reuse, recycle
- By reducing our consumption, we reduce the need for raw materials like wood. which in turn reduces deforestation
Introduce environmentally friendly practices
- Initiatives like “Bring Your Own Bag” encourages us to be more environmentally friendly
- Helps reduces emission of greenhouse gases, hence, the effects of climate change
Reforestation
- Protects soil, which stores carbon
- Plants take in carbon dioxide during photosynthesis. They help to store carbon and reduce the amount of carbon dioxides in the air
What is a habitat?
Where an organism lives
- Each habitat has a certain environment
- Different environments are distinguished by physical factors: air, water, temperature, light, minerals, acidity, alkalinity
Hot desert
> Due to extreme temperatures and lack of water, life is not abundant in hot deserts. Few plants and animals can survive the harsh conditions of hot deserts
Cold desert
> Due to the extreme cold, regions near the North and South Pole have a lot of water in the form of ice. Only plants with shallow root systems and mature quickly can survive in the long periods of darkness during winter months.
These plants grow in a thin layer of soil free from ice. Few animals live in cold deserts
How do organisms survive in an environment
Only organism suited to their specific environment live long enough to reproduce. They have adapted/have adaptive traits to enable them to thrive/grow well in their environment
Two types of adaptive traits
- Structural adaptations
- Behavioural adaptations
Structural adaptations
Physical characteristics of an organism that help it to survive in its habitat
Behavioural adaptations
Different behaviours of an animal that allow it to survive in its habitat
Adaptation in organisms
When environmental conditions change, those which are unable to survive will die.
Thos which survive go on to reproduce and pass down these adaptive traits to their offspring so that they can survive as well
How an environment affects the adaptive traits of organisms living in it
Physical factors of an environment shape the adaptive traits of plants an animals that live in it
What is an ecosystem?
An ecosystem is made up of the interactions between a community and its environment
Organism
Usually adapted to the environment it lives in, a singular organism
Population
Organisms of the same kind living in the same environment
Community
Different populations of plants and animals living in the same environment
Ecosystem
Interactions between a community and its physical environment
Typers of inter-relationships in an ecosystem
- Predator-prey
- Mutualism
- Parasitism
Predator - Prey relationship
Predators hunt and kill prey for food
Predators
- Have adaptations which help them at hunting prey: Sharp teeth, sharp claws, high speed and sharp senses for detecting prey
- Different hunting strategies (mimicking prey)
Prey
- Have adaptations which help them from being detected by predators: High speed, small size, effective camouflage and defensive body parts (horns)
- Some mimic unpleasant objects to deter their
predators
Mutualism
In which two or more organisms support or benefit one another (e.g. one provides protection while the other provides food)
Examples of mutualism
African Weaver Ants protect the scale insects from predators. In return, the ants feed on the sugary solution produced when the insects feed on plant sap
Parasitism
An organism that harms another organism (its host) without killing it
- Parasite benefits by obtaining food or nutrients from the body of the host which can be a plant or an animal.
Importance of maintaining the interrelationships between organisms in a community
This results in a stable ecosystem
Changes in environmental conditions or removal or sudden addition of an organism can disrupt the stability of the ecosystem
- If this happens, some organisms may decrease in number or go extinct
Energy from food in plants
Green plants are producers. They make food using carbon dioxide and water in the presence of light through photosynthesis
What can the food be used for
Food produced can be used as energy for life processes in plants
- Occurs through a chemical reaction known as cellular respiration
- Plant cells break down food substances through respiration to release energy in the presence of oxygen
> energy released by plants is used for growth
> Some energy is stored as CPE (Chemical potential energy)
How do animals obtain energy
Animals obtain energy when they feed on plants, other animals or both. They are known as consumers. Chemical potential energy is used by a consumer during respiration
Flow of energy and nutrients in food chains and webs
Feeding relationship between one organism and another is represented by arrows in a food chain. During feeding, energy and nutrients are transferred from one organism to another.
Producer
Makes food using energy from the sun which is stored as chemical potential energy (Green plants)
Primary consumers
Feed on producer to obtain energy and nutrients (Grasshoppers, worms, caterpillars, herbivores)
Secondary consumers
Feed on primary consumers to obtain energy and nutrients (Frogs and Spiders)
Tertiary consumers
Feeds on secondary consumers to obtain food and energy (crows and eagles)
Food webs and chains
Shows how one or more food chains are interconnected. Gives an overall picture of all the organisms involved in the transfer of energy and nutrients in an ecosystem
Producers are at the start of all food webs and chains as they are the only organisms who can make their own food using light energy from the sun
What is involved in the flow of energy
In an ecosystem, flow of energy occurs with the flow of nutrients.
Photosynthesis and respiration are involved
Flow of energy
- Producers absorb light energy from the sun, which is used to produce food through photosynthesis. Food produced is stored as chemical potential energy
- Producers respire to release energy required for their life processes such as transport of substances - Consumers obtain this energy by feeding on plants, animals or both
- They respire to release energy stored in food
- They release energy stored in undigested food, which is passed out by faeces - Decomposers feed on the remains of dead organisms and faeces
- They release energy through respiration - At each stage, about 90% of the energy is released into the environment as heat energy
- The last organism in the food chain receives the least amount of energy from the sun
Energy release
Energy is released in the form of heat into the surroundings by each organism in a food chain or food web in an ecosystem.
This energy cannot be reused by producers for photosynthesis. Thus, the flow energy is one-directional. Not cyclical.
Flow of nutrients
When plants and animals die, decomposers break them down. Energy is transferred and nutrients within the dead organisms return to the environment. Thus the Flow of nutrients is cyclical
Decomposers
Decomposers break down dead plants, dead animals, and waste products like faeces. (Decomposers: Bacteria, Fungi, Termites, Earthworms)
Importance of decomposers
Nutrients found in the environment and waste would not be returned to the environment without decomposers
What does a stable ecosystem require
The maintenance of interrelationships between organisms such as: predator-prey, mutualism and parasitism
Flow of energy is _______
One - directional
Flow of nutrients is ________
cyclical
