B4 Ecosystems Flashcards
What process do plants use to produce their own food?
Photosynthesis
What is the pigment that absorbs sunlight inside the leaf?
Chlorophyll
Which sub-cellular structures in a plant cell carry out photosynthesis?
Chloroplasts
What is the word equation for photosynthesis?
Carbon dioxide + water → oxygen + glucose
What gas is produced during photosynthesis?
Oxygen
What are the two reactants involved in photosynthesis?
Carbon dioxide and water
What are the two products involved in photosynthesis?
Oxygen and glucose
Give three uses for glucose in a plant.
Respiration, making cell walls and converting to starch for storage
What substance is used to test for the presence of starch?
Iodine
Name three adaptations of a leaf.
Large surface area, thin and contains chlorophyll
Explain why leaves have large surface areas.
To absorb more sunlight
Explain why leaves are thin.
To give a short diffusion pathway
Explain why leaves have chlorophyll.
To absorb sunlight for photosynthesis
Name the five layers of a leaf.
Waxy cuticle, upper epidermis, palisade mesophyll, spongy mesophyll and lower epidermis
What are stomata?
Small gaps on the bottom of leaves
In which layer of a leaf are the stomata found?
Lower epidermis
What is the function of the stomata?
Allow oxygen to leave and carbon dioxide to enter the leaf
What are the guard cells?
Curved cells found on the bottom of leaves
What is the function of the guard cells?
To open and close the stomata
What is the waxy cuticle?
A thin layer found on the top surface of the leaf
What is the function of the waxy cuticle?
To stop water loss from the leaves
Name an adaptation of the palisade mesophyll cells.
Contain lots of chloroplasts
Explain why palisade mesophyll cells have lots of chloroplasts.
To absorb more sunlight for photosynthesis
What is the purpose of the air spaces in leaves?
To allow gases to diffuse in and out of the leaf
What is a feeding relationship?
Which organisms eat each other
Why do organisms eat each other?
To get nutrients and energy
What diagrams do scientists use to show feeding relationships?
Food chains
What name is given to organisms that make their own food?
Producers
Where do producers get their energy from?
The Sun
In a food chain, what name is given to an organism that eats another organism?
Consumer
In a food chain, which direction do the arrows point?
From the organism being eaten to the organism eating it
In a food chain or web, why do the arrows point from the organism being eaten to the organism eating it?
To show the flow of energy
What is bioaccumulation?
How toxic materials can build up in a food chain
What name is given to organisms that eat animals?
Predators
What name is given to animals that are eaten by other organisms?
Prey
What happens to the number of prey if the number of predators increases?
The number of prey decreases as more are eaten
What happens to the number of predators if the number of prey decreases?
The number of predators decreases as they starve
What is a herbivore?
An animal that eats plants
What is a carnivore?
An animal that eats other animals
What is an omnivore?
An animal that eats plants and animals
What is the ‘population’ of an organism?
The number of that organism in a particular area
What is interdependence?
How organisms depend on each other for survival
What is a food web?
A group of interconnected food chains
What is an adaptation?
A way in which an organism suits its environment
What is heredity?
The process by which genetic information is transmitted from one generation to another
What is DNA?
A genetic code
Where is DNA found in a cell?
In the nucleus
What is a chromosome?
Long chain of coiled DNA
What is a gene?
A section of DNA coding for a protein
In biology, what is variation?
Differences between organisms
What is genetic variation?
Differences caused by DNA
What is environmental variation?
Differences caused by the environment
State two examples of genetic variation in humans.
Eye colour and ear lobe shape
State two examples of environmental variation in humans.
Scars and tattoos
State two examples of variation caused by environmental and genetic variation.
Height, the foods a person likes to eat
Why are we not genetically identical to our parents?
We inherit half of our DNA from each parent
What do animals compete with each other for?
Food, mates, territory
What do plants compete with each other for?
Light, water, minerals, space
What is an adaptation?
A feature that enables an organism to survive
Darwin’s theory of evolution occurs through which process?
Natural selection
What is evolution?
A change in inherited characteristics of a population over time
What are offspring?
The organisms produced in reproduction
What is meant by biodiversity?
The range of different species in an area
What is a species?
Organisms that have similar characteristics and can reproduce with each other to produce fertile offspring
