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Biology Nat 5 unit 3 - Ecosystems


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[Front]


What type of competition is the most intense
[Back]


Intraspecific competitions as the organisms require the exact same resources

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Biology Nat 5 unit 3 - Ecosystems - Details

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98 questions
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What type of competition is the most intense
Intraspecific competitions as the organisms require the exact same resources
What type of competition is the most intense
Intraspecific competitions as the organisms require the exact same resources
What is is species
A species is a group of organisms so similar they can interbreed to produce the fertile offspring
What is a Biosphere
The zone of the earth inhabited by living organsims
What is a Habitat
The place an organism lives
What is a Community
All of the organisms in a habitat
What is a Population
All of the organisms of one type
What is an Organisms
A living thing
What is an Ecosystem
The habitat, animals and plants
What is Biodiversity
The number of different species present in a particular area
What is the role of a Producer
To photosynthesis to produce food. At death they provide food for decomposers
What is the role of a Consumer
To obtain their energy by eating other organisms
What is the role of a Primary Consumer
To obtain their energy by eating producers. At death they provide food for decomposers
What is the role of a Secondary Consumer
To obtain their energy by eating primary consumers. At death they provide food for decomposers
What is the role of a Omnivore
To eat plants and animals
What is the role of a Top Carnivore
To not be eaten by any other animal. After death they provide food for decomposers
What is the role of Prey
Animals that are eaten by a Predator
What is the role of a Predator
Animals that hunt and kill other animals
What is the role of a Decomposer
To obtain their energy by breaking down waste, uneaten remains and dead bodies.
What do the arrows of a Food chain show
The direction of the energy flow
What is a Niche
The role an organism plays within a community
What are 3 resource in an Ecosystem
Nutrients available, Light and Temperature
What are 3 interactions in a Niche
Predation, Parasitism and Competition
What do plants compete for in the same habitat
Water, Space, Sunlight, Nutrients
What do animals compete for in the same habitat
Water, Food, Shelter/Territory and Mates
What is Interspecific competition
Individuals of different species compete for similar resources in an ecosystem
What is Intraspecific
Individuals of the same species competing for exactly the same resources
What type of competition is the most intense
Intraspecific competitions as the organisms require the exact same resources
What is the photosynthesis equation
Carbon dioxide + water →light → sugar + glucose
What does the first stage involve in photosynthesis
Light energy being trapped by chlorophyll
What does the second stage result in in photosynthesis
The production of carbohydrates which can be stored as starch
Describe an Indicator Species
A species by their presence or absence indicates environmental quality
Describe an Indicator Species
A species by their presence or absence indicates environmental quality
Describe an Indicator Species
A species by their presence or absence indicates environmental quality
3 examples of biotic factors
Food supply, Predation, Disease
3 examples of abiotic factors
Temperature, Light intensity, Soil moisture
How to measure light intensity
Use a light meter Direct sensor towards the light source Read correct scale
What are the limitations and source of errors of light intensity
Light intensity could change during the sampling process - cloud cover Light sensor could be covered by your shadow
What are the ways to minimise these errors of light intensity
Take all readings at the same time each day or take multiple sampling at each place and take an average Make sure the light sensor does not have a shadow over it
How to measure temperature
Use a Thermometer/Temperature probe Do not cover sensor Read correct scale
What are the limitations and source of errors of temperature
Thermometer or probe may not be inserted deep enough into soil Bulb or thermometer may be held by hand Thermometer may be in direct sunlight
What are the ways to minimize these errors of temperature
Push thermometer or probe into the soil until half of it is in Allow reading to stabilise before attempting to take reading Do not hold bulb and ensure thermometer is in the shade when measuring air temperature
How to measure the PH
Use a PH meter Place the clean probe in the soil/water Read correct scale
What are the limitations and source of errors of PH
Reading may be contaminated by soil/water left on probe from previous samples Not enough samples taken
What are the ways to minimize these errors of PH
Wipe probe between sampling to reduce cross-contamination Increase numbers of samples taken
How to measure the Soil moisture
Use a moisture meter Place the clean probe into the soil Read correct scale
What are the limitations and source of errors of soil moisture
There may be moisture on the probe from past readings Not enough samples taken
What are the ways to minimize these errors of soil moisture
Wipe probe with a paper towel before and after taking each reading Take a repeat for each sample site and calculate an average
What are Quadrats used for
Plants and very slow moving organisms
How do you use Quadrats
They should be placed randomly so that a representative sample is taken The number of squares where the organism is present is counted Replicate to give a representative sample of the area
What are the limitations and source of errors of Quadrats
Can only be used for stationary or slow moving organisms Depends largely on human accuracy Incorrect identification/counting Non-random sampling
What are the ways to minimize these errors of Quadrats
Use a key to make sure the organisms are correctly identified If organisms are only in a part of the quadrat make a rule for counting them If organisms are in a cluster increase the number of samples
How do you use a pitfall trap
Bury a container with drainage holes, level with the ground Protect the trap from rain by placing a piece of raised wood or slate above the trap Leave the trap overnight
What are the limitations and source of errors of pitfall traps
Only traps animals on the ground Time consuming Incorrect identification Predation occurs if left to long Non-random sampling
What are the ways to minimize these errors of pitfall traps
Dig the hole deep enough to ensure the trap is level with the ground Empty trap regularly Place small holes in the bottom to allow drainage Use a key to identify animals
What is a Key used for
To enable correct identification
What happens when Over-Grazing occurs
Happens when the herbivore population is high. More animals feed on limited plants. Biodiversity is reduced.
What happens when Under-Grazing occurs
Happens when the herbivore population is low. Less plants are eaten. Biodiversity is reduced
What happens when Moderate-Grazing occurs
Can increase Biodiversity. Allows less dominate plants to grow as they have more light and soil nutrients
What happens when lots of Predation occurs
Causes prey specie diversity to fall - everything gets eaten
What happens when little Predation occurs
Causes prey species to compete with each other, only the best competitors survive - diversity falls
What happens when Moderate Predation occurs
Keeps the number of best competitors down so different species can thrive/survive - high biodiversity
Describe Pollution and give 3 examples
Environmental pollution is contamination by a pollutant, which harms living organisms eg causes distress, disease or death
Describe an Indicator Species
A species by their presence or absence indicates environmental quality
Ways in which energy is lost
Heat, Waste, Movement
What does a pyramid of numbers show
The amount of organisms at each stage of the food chain
What is Exponential growth
Nothing limiting a populations size
What are fertilisers used for
Adds extra nitrates to the soil to increase and speed up plant growth
What are pesticides used for
To kill pests that destory/ eat crops
Describe the use of nitrates in a plant
To make amino acids (Nitrates → amino acids → proteins)
Describe the stages of Algal Bloom
1- Fertilizer leach into water adding unwanted nitrates 2- Increase Algal populations which reduces sunlight from getting to aquatic plants 3- The plants die then becoming food for bacteria 4- The bacteria take up lots of oxygen reducing oxygen availability for living organisms like fish so they die
Why do you have to be careful when using pesticides
They can accumulate in the crop and can be eaten by consumers
What is Biological control
The use of living organisms instead of chemicals to kill pests
How can Genetically modified crops help
Crops can be genetically modified to become resistant to pests
What is Bioaccumulation
Pesticides sprayed onto crops can gatherin the bodies of organisms over time, as they are passed along the food chain, toxicity increases and can reach lethal levels
What is a Mutation
A random and permanent change to the DNA of an organism
What are 2 mutagenic agents
Radiation - x-rays and UV lights Chemicals - mustard gas and caffeine
Why is variation important
To allow the population to evolve over time in response to changing environmental conditions
What are Adaptations
They increase their chances of survival and reproduction
What are the 3 Adaptations
Structural - what the organism looks like Physiological - how the organism works Behavioural - what the organism does
What is Natural selection
When species produce more offspring than the environment can handle. It occurs when there are selection pressures (survival of the fittest)
What is the result in Natural selection
The best adapted individuals survive to reproduce and pass on the best allele that give them a selective advantage
What are the 4 stages of Natural Selection
1 - There is variation in the population 2 - The environment cannot support an unlimited population, so the individuals who are less well adapted die and do not reproduce 3 - The best adapted individuals reproduce producing individuals with similar genetic traits 4 - The most advantageous traits become more common in the population
What are the 3 reasons why the population become isolated
Geographic - sea, river, mountain, desert Behavioural - different breeding time, different mating display Ecological - areas have different temperatures, water availability, pH
What are the 4 stages of Speciation
1 - Isolation - Geographic, Behavioural, Ecological 2 - Mutations - occur in both populations, mutations are needed to create new alleles in each of the populations 3 - Natural Selection - Occurs whenever a mutation gives members of the subpopulation a selective advantage 4 - Over Time - The gene pool of each population changes. The 2 populations are 2 different species
What is a Species
A group of organisms that are so similar they can interbreed to produce fertile offspring