Biology Edexcel topic 9

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this is about ecosystems and the environment and food security
Emily Cosh
Flashcards by Emily Cosh, updated more than 1 year ago
Emily Cosh
Created by Emily Cosh almost 4 years ago
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Question Answer
what does interdependence mean the survival of species is dependant on other living organisms and non living components
what is the importance of interdependence if the population of one organism rises or falls, then this can affect the rest of the ecosystem
what does ecosystem mean a biological community of interacting organisms and their individual environment
what is a community all the interacting organisms in an area, doesn't include non living factors
what is a population all of the organisms of 1 type of species in the area
what is a habitat a place where organisms live
what does it mean by the term biotic factors and what are they living parts of ecosystems - competition: all living organisms "fight" for things such as sunlight and food -predation: when predators prey on their prey the levels of both prey and predator fluctuate
what does it mean by the term Abiotic factors and what are they non living parts of ecosystems -temperature -water -light intensity -pollutants
what do animals fight for -food -water - mating -partners -territory
what do plants compete for -light water -minerals from soils -bees to pollinate
define the term predator animals that eat other animals
define the term prey animals eaten by other animals
what is a population explosion an increase in the population of a organism
what is a population crash a decrease in the population of an organism
what is one example that can cause a population crash and explosion crash: predators hunting healthier prey explosion: more food
what is a mutualistic relationship, give an example both creatures definite from being around each other eg hammerhead sharks and fish like surgeon fish
what is a commensalistic relationship and give an example when on creature benefits and the other is relatively unaffected eg ants and aphids
what is a parasitic relationship and give and example when on creature benefits at the expense of another eg fleas and other animals
how is energy transferred to plants by light usually form the sun
how does energy transfer from plants to animals consumption
what is eutrophication -fertilizers (which have a high level of nitrogen) spread on the land by farmers -the fertilizer is washed away by the rain and absorbed by the soil -the fertilizer is transported to a lake by underground water -the presence of the fertilizer causes overgrowth of algae -no sunlight can reach the lower parts of the lake causing algae to die -bacteria decomposes algae when doing this all oxygen is used up making it anoxic -all animals die since they cant do respiration due to the lack of oxygen
what are the negative human effects of biodiversity eutrophication fish farming
what are the issues with fish farming reduces biodiversity food added to tanks can leak causing death of wild they act as breeding ground for parasites
what are the positive human effects of biodiversity conservation schemes reforestation
what are some conservation methods protecting natural habitats protecting a species out side their natural habitat eg zoos reduce impact of harmful necessities such as farming
what is reforestation and what must it include re planting of trees since forests have high biodiversity therefore a rang of tree species should be planted in the programme
what is the indicator species for AIR pollution lichens they are a tiny living organisms that grow outdoors on things such as rocks trees and soil. it is a result of the symbiotic relationship between algae and fungi. they only grow in clean aired environments. the fungi gives the lichen strength and the algae brings in food
what is the indicator species for WATER pollution in polluted water = mostly worms and leaches in slightly polluted water = snails and some beetles clean water = shrimp and stonefly
what is food security the state of having reliable access to a sufficient quantity of affordable, nutritious food.
what is the importance of food security more food is required for the increase of population to still have the same amount of food supplied to each person
how is environmental changes effecting food security global warming causes other climate changes such as changes in rainfall patterns. this could decrease crop growth resulting in less crop yield therefore not enough food to feed the growing human population.
what does sustainability mean meeting the needs of todays population with out affecting the needs of the futer generations
how does sustainability effect food security since biofuels are alternatives to fossil fuels but take up lots of land which could be used for farming. therefore there must be a balance between biofuels and food for the future
how do pest and pathogens effect food security they can damage crops and livestock. if they aren't resistance to patristics than they can be damaged or killed
how to combat food security issues -consuming locally grown food -eating freshly grown food( doesn't rely on factories) -wasting less food(less food need to be made, transport reduced) -eating less meat( methane gas not produced, less space needed)
what is the water cycle and the stages of it the water cycle is the movement of water through the earths layers -water from the ocean evapourates and water from plants/leaves transpires -then it condenses to form clouds -eventually the water droplets become too heavy and fall called percipitation
what is the carbon cycle carbon is passed from the atmosphere as carbon dioxide to living things. it the then passed from one organism to another in complex molecules and can return to the atmosphere when decomposition happens or the burning of fossil fuels or respiration
what is the difference between decay and fossilisation decay occurs in the presence of oxygen for microbes if there is no oxygen the fossilisation happens
what is the nitrogen cycle nitrogen in the air becomes nitrates in the soil this is caused by lightening, nitro fixing bacteria and nitrifying bacteria in the soil this is absorbed by plants and become nitrogen compounds such as amino acids and protein these can be spread to animals by digestion when animals and plants die they become nitrates in the soil again, due to decomposing bacteria then they become nitrogen gas in the air again by denitrifying bacteria
what does -nitrifying bacteria -nitrogen fixing bacteria -denitrifying bacteria do nitrifying = turns ammonia into nitrates nitrogen fixing = atmospheric nitrogen into ammonia and ammonia ions denitrifying = turns nitrates back into nitrogen gas
what are the conditions for decay to take places temperature = warm oxygen = most of the time it is needed water = water is needed, lack of it will prevent transportation.
why is decay important there would be no way for nutrients to return to the soil without decay, in result would kill off many plants and therefore animals. it would also eventually reduce the amount of nitrogen in atmosphere
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