Topic 3: Life on Earth Flashcards
Ecosystem
All the organisms living in a particular habitat and the nonliving components with which the organisms interact.
Habitat
The place where an organism lives
Population
All of the organisms of ONE species in an area
Herbivore
An animal that only eats plants
Carnivore
An organism that only eats animals
Decomposer
An animal that feeds on dead or decaying material
Omnivore
An animal that may eat both plants and animals
Prey
An animal that is hunted and killed for food
Predator
An animal that kills other organisms for food
Consumer
An organism that eats other animals or plants to gain energy
Food web
A diagram showing how all of the organisms in a community are linked together
Food chain
A diagram that shows the feeding relationship from the producer to the final consumer
Species
A group of organisms with similar characteristics that can interbreed and produce fertile offspring
Community
A group of organisms of different species living in the same place
Biodiversity
The variety of species in a community
Producer
A green plant that is able to produce food by photosynthesis
Biome
The various regions of our planet which can be distinguished by their climate, fauna and flora
Food chain
A diagram that shows how organisms are dependant each other for food (predator/prey relationship)
What is grass? (P, PC, or SC)
Producer (P)
What is a rabbit? (P, PC or SC)
Primary consumer (PC)
What is a fox? (P, PC, or SC)
Secondary consumer (SC)
What do all food chains start with?
Producer (a green plant)
What do arrows show in a food chain/web?
The direction of energy flow between organisms
Food web
Many food chains joined together, much more complex than a food chain
Interpendence
Describes how all organsisms within an ecosystem interact and depend on one another
If the number of organisms in one population changes in size (increases/decreases), what is it going to affect?
Other organisms, even those who are not directly linked to that species
What is competition?
The interaction that occurs between organisms when they require the same limited resources. To ensure they get enough resources available, they compete for them.
What do plants compete for?
Light, soil, nutrients and water
What do animals compete for?
Food, water, shelter and mates
Inasive species
A species of organism that it not native to a particular country
Why can insaive species upset the balance of interpendence between native organisms?
Because they can cause an increase in the intensity of competiton for already limited resources
Interspecific competiton
Individuals of DIFFERENT species who compete for the same resources in an ecosystem
Intraspecific competiton
Individuals of the SAME species that compete for exactly the same resources
Which competiton is the most intense and why?
Intraspecific because the organisms require exactly the same resources. This type of competiton often leads to territoriality
Terriroriality
Competiton between members of the same species for territories. This is to ensure thet the animal has a safe space to breed and have enough food
What often happens when two different species require the same resource?
Competiton may become so fierce that one species tends to force the other out
Niche
The role an organism plays in an ecosystem. This includes information on its interactions with other organisms in the community. The use it makes of resources such as light and nutrient availability
What does niche involve?
Competiton, predation and the conditions it can tolerate, such as temperature
No two species can…
occupy the same niche in an ecosystem
If two species have identical needs, what would they be in?
Direct competiton for resources and one species would eventually become extinct
If two species have different roles, what does that mean?
They are both able to successfully live in the same ecosystem
How is energy lost in a food chain/web?
- Some food is undigested and passed as faeces
- Some is used for movement (kinetic energy)
- Some is used to keep warm (heat energy)
How much energy is passed on to the next organism?
A small quantity
Pyramid of numbers
Indicates the relative number of organisms at each stage in a food chain
What is found to be the most numerous in a pyramid of number?
Producers
Pyramid of energy
Represents the quantity of energy (kJ) at each stage in a food chain
Which pyramid shape doesn’t take a pyramid shape?
Pyramid of number
Biotic factor
Any LIVING component that affects another organism
Examples of biotic factors (6)
- Predation
- Grazing
- Competiton
- Food availability
- Diseases
- Trampling
Abiotic factor
Any NON-LIVING component of the ecosystem that affects an organism
Examples of abiotic factors
- Temperature
- Moisture
- Light intensity
- pH
What is a biological key?
A method of identifying different species of organisms
Two main types of keys
- Paired statement key
- Branched key
What does a study of an ecosystem involve?
- Finding out which plants and animals live there
- Finding out how abundant organisms are
- Investigating biotic, abiotic and human factors that might affect where the organisms live
Quadrats
A squared frame that measures the abundance of species
Quadrats key points
- Should be placed randomly so it is representive
- Many should be placed so that it is reliable
- Can be used to measure slow moving animals
Pitfall traps
A simple device used to catch small invertebrates on the ground
Pitfall traps key points
- Used to sample small invertebrates living on the ground
- Likely to trap beetles and other insects
- Repeats of the experiment make it more reliable
Pollution
Is the presence of a substance that has harmful or poisonous effects
Indicator species
Species whose presence/absence indicate the enviromental quality/pollution levels
If we find lots of one species, and not many of another species, what does this tell us?
The pollution levels
Lichens
An organism that are highly senstive to air quality. Because of this, they are used as indicator species to detect sources of pollution
Why are green plants called producers?
Because they can produce their own food by photosynthesis
Raw materials for photosynthesis
Carbon dioxide and water
Essentials for photosynthesis
Light energy and chlorophyll
Products of photosynthesis
Glucose and oxygen
Word equation for photosynthesis
Carbon dioxide + water (light energy) ——-> (chlorophyll) glucose + oxygen
Where in a cell, does photosynthesis take place?
Chloroplasts
What captures the sun’s energy?
Chlorophyll
What are the 3 ways that photosynthesis can be measured?
- Counting the number of bubbles produced in a set period of time
- Measuring the volume of oxygen produced in a set period of time
- Using data loggers to measure oxygen production or CO2 consumption
What will happen if a leaf does not have it’s materials for photosynthesis?
The leaf will not photosynthesize or contain any starch
What controls photosynthesis?
Enzymes
What are the two stages of photosynthesis?
Light reactions and Carbon fixation
What is ATP?
A high energy molecule important to all living cells
What does ADP + Pi regenerate into?
ATP (using light energy)
Light energy is conveted to…
chemical energy
Light reactions
- Light energy is trapped by the clorophyll inside the chloroplasts and used to split a molecule of water
- Water is split in two, producing oxygen which diffuses from the cell and hydrogen which is passed on to carbon fixation stage.
- Light energy is needed to break bonds in a water molecule, but during the process of splitting water, a burst of energy (ATP) is released
ADP + Pi —> ATP, which is passed on to carbon fixation
