Unit 3 Life On Earth Flashcards
What is the definition of Biodiversity
Total variety amongst all living things on earth
What is the definition of Abiotic factor
Non living factors that can effect the distribution of organisms
What is the definition of Biotic Factor
Living factors that can effect the distribution of organisms
What is the definition of a carnivore
An animal which only eats animals
What is the definition of a community
Community - all of the animals and plants that are living in one area
What is the definition of a consumer
Organisms that feed of another organisms
What is the definition of an ecosystem
An ecosystem consists of all organisms living in a particular area and the non living components with which they interact
What is the definition of a Food chain
A sequence that shows feeding relationships and the transfer of energy between organisms
What is the definition of a food web
Food chains that are linked to show the complex feeding relations in a habitat
What is the definition of a habitat
A habitat is the place where an organisms live
What is the definition of a omnivore
Organisms that feeds on both animals and plant materials
What is the definition of a population
A Population is groups of organisms of one species living in an area
What is the definition of a Producer
Organisms that produce its own food
What is the definition of Species
A group that can interbreed to produce fertile offspring
What is the definition of a Niche
A Nichte is a role that an organisms plays within a community
What is the definition of a Herbivore
Organisms that feeds on the plant material
What our abiotic factors
Moisture
Light intensity
PH
Temperature
What our biotic factors
Competition for resources (e.g food and space)
Diseases
Predation
Grazing
What is the definition of a Independent variable
The variable that is changed in an experiment
What is a control
It is a comparison
What Can you use to measure light intensity
A light Meter
What Can you use to measure soil moisture
Moisture meter
What Can you use to measure temperature
Thermometer
What Can you use to measure pH
Ph probe
What’s a source of error when measuring light intensity
A shadow may be cast on the light meter
What’s a source of error when measuring soil moisture
Moisture left on probe from previous reading
What’s a source of error when measuring temperature
Thermometer not left long enough
What’s a source of error when measuring pH
Contamination from previous sample
How to minimise error when measuring light intensity
Ensure that nobody is covering the light meter
How to minimise error when measuring soil moisture
Wipe the probe between each reading
How to minimise error when measuring temperature
Allow thermometer to settle before taking the reading
How to minimise error when measuring pH
Clean the probe between each reading
When do competition occur in the ecosystem
When resources are in short supply
Finish the sentence
Interspecific competition occurs amongst..
Individuals of the different species for one or a few of the resources they require
Finish the sentence
Intraspecific competition occurs amongst..
Individuals of the same species and is for all resources required
Out of Interspecific and Intraspecific competition which is more intense
Intraspecific
Finish the sentence
A pitfall trap is used to..
Collect sample ground invertebrates
How do you sit up a pit fall trap
A cup is place level with the grounds and covered by leaves to camouflage it allows grounds animals to fall in. Organisms collected then counted
What sources of error are in a pitfall trap and how do we minimise the errors
Birds may eat trapped animals
-make sure the trap is camouflaged
Some animals may eat others
-check traps regularly
What are indicator species
Organisms that indicate levels of pollution or environment quality by their presence, absence or abundance in the environment
What are examples of an indicator species
Lichens, daphnia
What are examples of an indicator species
Lichens, daphnia
What’s the formula for percentage increase
Percentage increase = difference/original number x 100
2 difference species =
Interspecific
Same species =
Intraspecific
What’s the word equation for photosynthesis
🩵🩵🩵🩵🩵🩵light
Carbon dioxide——————-> Glucose +
🩵🩵+water.🩵Chlorophyll 🩵Oxgen
What are the raw materials in photosynthesis
Carbon dioxide and water
What are the conditions of photosynthesis
Light
And chlorophyll
What are the products of photosynthesis
Glucose and oxygen
What is stage 2 of photosynthesis
The ATP and hydrogen generated from the light reactions and carbon dioxide from air are combined. They are converted into sugar during a series of enzymes controlled reaction
What is chlorophyll
A chemical found in chloroplast that is able to trap light energy
What is stage 1 of photosynthesis
The light energy from the sun is trapped by chlorophyll in the chloroplasts some of this light energy is converted into chemical energy which is used to generate ATP the remaining light energy is used to split water into oxygen and hydrogen the oxygen is diffused from the cell
What is a pyramid of numbers
A diagram of the total numbers of of organisms at each stage of a food chain
What is a pyramid of energy
A diagram of the total energy contained within each stage of the food chain
What are the tree ways energy is lost along a food chain
Heat, movement, undigested materials
True of false pyramids of numbers can be irregularly shaped
True
True or false a pyramid of energy can be irregularly shaped
False, it is always pyramid shaped
What methods can we use to increase food yields
Use fertilisers or use gm crops
How do we prevent pests from damaging crops
Use pesticides, GM crops or use a biological control
Why do people use fertilisers
To increase crop yield
What is an advantage of fertilisers
They increase crop yield
What is a disadvantage of fertilisers
They can leach into fresh water
Why do people use pesticides
To prevent damage to crops
What is one disadvantage of pesticides
Causes bioaccumulation in food chains
Why do people use GM crops
To increase crop yields and to prevent crop damage
What is a disadvantage of GM crops
They are expensive
Why do people use biological controls
To prevent damage to crops
What is an advantage to using biological controls
No chemicals are required
What is one disadvantage of biological controls
They are difficult to manage
Fertilisers provide chemicals such as nitrates how does this increase crop yield
Nitrates are used to produce amino acids which are synthesised to make plant proteins
What happens when fertilisers leach into water (algal bloom)
- Fertilisers leach into the water
- There is an increase in algal populations, this is known as an algal bloom
- Algal blooms reduce light levels killing aquatic plants
- The dead plants become food for bacteria. The bacteria increase greatly in number
- The bacteria use up large quantities of oxygen, reducing the oxygen availability for other organisms such as fish.
What is bioaccumulation
When pesticides are sprayed onto crops they can accumulate in the bodies of organisms over time as they are passed along food chains they increase in toxicity and can reach lethal levels
What are alternatives to pesticides and fertilisers
GM crops and biological controls
What is a mutation
The random change to an organisms genetic material.
What three things can a mutation be described as
Advantageous, disadvantageous and neutral.
What causes mutations
Mutations are spontaneous but some environmental factors like radiation a di some chemicals can increase the rate of mutation
What causes natural selection
Selection pressures weather that is the environment, availability of food or new predators
What is natural selection
The name of a scientific theory that explains how evolution happens
What are the steps of natural selection
- Species produce more offspring that the environs can sustain.
- The best adapted individual in a population survive.
- The survivors reproduce and pass on favourable alleles with the selective advantage.
- The favourable alleles increase in frequency within the population
What is speciation
The process of a new species evolving
What are the three major steps of speciation
Isolation, mutation and natural selection
What are the three types of barriers
Geographical, ecological and behavioural
