7G Ecosystems Flashcards
What does a food chain show?
How organisms get their energy
What do the arrows represent?
Transfer of energy from one organism to another
How do plants make their own food?
Photosynthesis
What eats other living things?
Consumers
What is a predator?
Animal that hunts and kills other animals for food
What organisms eat producers?
Primary consumer
What organisms eat both plants and animals?
Omnivores
Name 3 predators.
Chiffchaff, lion, cheetah, shark
What is a food web?
Multiple food chains together
Name the two top predators in the food web shown.
Fox and hawk
What can a food web tell us about changes in populations?
If they impact on another organism, directly or indirectly
What would happen in the food web if the grass died?
Consumer populations would decrease
What would happen if the foxes died?
Vole, frog and rabbit populations may increase
What do trophic levels show us?
Different levels of the food chain
Why does the number of organisms decrease?
Energy is lost from the food chain at each trophic level
What type of organism are found at the top of a pyramid of numbers?
Tertiary consumers
Why does a predator need to be well adapted?
For hunting, to catch their prey
Why do predators need front-facing eyes?
Judge distance
Why do prey need to be well adapted?
To escape predators
Why do prey need to be camouflaged?
Avoid being seen
What happens to predator numbers if there are more prey?
Increase
What happens to predator numbers if there is less prey?
Decrease
Give 2 examples of predator-prey relationship.
Fox and rabbit, Cat and mouse, Lion and zebra, etc.
What is the main idea of a predator prey relationship?
There are always more prey and there is a time difference between the peaks of each population
What is bioaccumulation?
Gradual accumulation of harmful substances in an organism
Why do some substances accumulate higher up the food chain?
They cannot be broken down and stay in the body
What organisms are most at risk due to bioaccumulation?
Predators/tertiary consumers
What effect do toxins have on an organism?
They can kill
What is a pesticide?
A chemical sprayed on crops
Why do farmers use pesticides?
To prevent crops being eaten
Name 2 poisonous chemicals.
DDT and mercury
Why do consumers have a larger concentration of chemicals than producers?
Consumers eat large numbers of producers
Why do plants have colourful flowers?
To attract insects
How do plants protect their buds?
Sepals
What is the female sex organ in plants called?
Carpel
What is the male sex organ in plants called?
Stamen
What are the male sex cells?
Pollen
Why do some plants have no flowers?
They are wind-pollinated
What protects the eggs in the middle of the flower?
Ovary
What features do both insect and wind pollinated plants have?
Stigma, anther, filament
What has to happen for plants to reproduce?
Pollination
What happens during pollination?
Pollen meets the stigma
What is the difference between cross and self- pollination?
Cross – different plants
Where does pollen go from and to?
Pollen goes from anther to stigma
What is fertilisation?
Pollen’s DNA is added to ovule’s DNA
What happens when pollen has been transferred?
Pollen tube grows to transfer sperm to the ovary
What happens when the nucleus of the sperm meets the ovule?
Develops into a seed
Where does the seed develop?
In the ovary
What is food security?
Reliable access to enough, affordable, nutritious food
Why are insects so important?
They pollinate our food crops
Give one reason why insect populations are decreasing.
Destruction of habitat and food sources, pesticides, global warming and climate change
Where are the lack of insects making a big impact?
South-west China
What is hand-pollination?
Using a paintbrush to transfer pollen from one plant to another
Why is hand pollination not a long-term solution?
More costly
Give one way we can increase insect populations.
Rewilding, reducing pesticides, installing hives
Apart from food security, why are insects important?
Provide food for other organisms
Why do seeds need to be dispersed?
To reduce competition
What do plants compete for?
Light, water, minerals and space
What features do seeds have to enable it to grow?
Stored food reserves, a strong outer layer
What does ‘to germinate’ mean?
To start growing
Give an example of a plant which disperses seeds using the wind.
Dandelion, sycamore
Why do some plants produce tasty fruits?
To attract animals to eat them and spread their seeds
How are peas dispersed?
Pods pop open
Suggest one factor which affects seed dispersal by wind.
Height, surface area, mass and wind speed
