Biology Nat 5 unit 3 - Ecosystems
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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 does a high Biodiversity indicate | A healthy ecosystem |
| 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 Herbivore | To only eat plants |
| What is the role of a Omnivore | To eat plants and animals |
| What is the role of a Carnivore | To only eat 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 |
| Where do the stages of photosythensis take place | In the chloroplasts |
| 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 |
| What is the layout of the first stage of photosynthesis | Light Dependent Stage |
| What is the layout of the second stage of photosynthesis | Carbon Fixation |
| What are the uses of sugar by plants | Sugar Use |
| What can the rate of photosynthesis be measured by | The Elodea Bubbler Experiment |
| 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 |
| What are aquatic environments now showing signs off | Acidification from pollution. |
| 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 |
| What don't dissolve into water easily so less algal blooms are formed | Manure and Compost |
| 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 |