Chapter 9 - Natural ecosystems and human activities Flashcards
What is an ecosystem?
An ecosystem is all the living things (biotic components) together with all the non-living things (abiotic components) in an area.
What is a population?
A population is all the organisms of one species living in a defined area.
What is a community?
A community is a group of populations of different species that live together in an area and interact with each other.
What is a habitat?
A habitat is the place within an ecosystem where an organism lives.
What is a niche?
A niche is the role of a species within an ecosystem.
What are biotic components?
Biotic is any living components of the environment that may affect other living things. E.g. producers, primary consumers, secondary consumers, tertiary consumers and decomposers.
What are abiotic components?
Abiotic is any non-living components of the environment that may affect living things. E.g. temperature, humidity, water, oxygen, salinity, light and pH.
What are the three biotic interactions?
The three biotic interactions are competition, predation and pollination.
What is competition?
Competition occurs because living things need a range of resources from the environment. Many younger are produced that will survive, so there is often competition for resources. Individuals least adapted to the current conditions will die or fail to reproduce.
What is predation?
Predation is when one animal eats another.
What is pollination?
Pollination is the transfer of pollen grains (male gametes) from the anther to the stigma for it to fuse with the ovule (female gamete). Pollen grains can either be blown by wind or carried by insects.
What is photosynthesis?
Photosynthesis is the process by which plants or plant like organisms make glucose in the form of carbohydrates from carbon dioxide and water using energy from sunlight. Carbon dioxide + water -> Glucose + oxygen. Plants trap light energy with the help of chlorophyll. It also splits water into hydrogen and oxygen.
How plants obtain the different components required for photosynthesis?
Plants obtain carbon dioxide from the atmosphere through their stomata in the leaves and water from the soil through their roots.
What is a food chain?
Food chain is a diagram showing the relationship between a single producer and primary, secondary and tertiary consumer. Food chains cannot have more than 4 or 5 trophic levels as there is not enough energy to pass on.
What is a food web?
Food web is a diagram that shows the relationship between all or most of the producers, primary, secondary and tertiary consumers in an ecosystem.
What is a trophic level?
Trophic level is a feeding level within a food chain or a food web.
What is a pyramid of numbers?
Pyramid of numbers is a diagram that represents the number of organisms at each trophic level in an ecosystem by a horizontal bar whose length is proportional to the numbers at that level.
What is a pyramid of energy?
Pyramid of energy shows the amount of energy at each trophic levels. It is always pyramid shaped. Only about 10% of energy is passed on to the next trophic level. The other energy is lost as heat, used for cellular respiration, growth, lost as faeces or lost by incomplete digestion by higher trophic levels.
What is the carbon cycle?
The carbon cycle shows how moves between the atmosphere, soils, living creatures, the ocean, and human sources. carbon dioxide in the atmosphere, fixation by photosynthesis in plants, plants die, animals feed on plants, animals respire, animals die, carbon is present in organic chemicals in dead matter such as humus, the is fossilised to form fossil fuels, organic matter respires and decays, fossil duels are burned.
What are seven advantages of wetlands?
Wetlands provide shoreline protection, maintenance of water quality, flood control, recharging of aquifers, biological productivity, provide habitats and are a source of a variety of products such as fish, fuel and fibres.
How does the drainage of wetlands lead to habitat loss?
The causes of habitat loss include drainage of wetlands for agriculture, forestry, mosquito control, flood protection, use of disposal waste created by road construction, discharge of pollutants, peat removal and the removal of groundwater, intensive agricultural practices as overcultivation of soil leads to soil erosion, causing habitat loss for decomposers living in the soil and deforestation as the clearance of climax communities that would otherwise provide habitat for a wide range of tree and ground dwelling species.
What are climax communities?
Climax communities are ecological communities in which populations of plants or animals remain stable and exist in balance with each other and their environment.
How does habitat loss lead to extinction?
Impacts of habitat loss include extinction which is the process by which a species or other name group ceases to exist on earth or another named area, loss of biodiversity which occurs when various species die or relocate when their habitat is destroyed, genetic depletion which is the loss of species containing potentially useful genes.
What are four causes of deforestation?
Causes of deforestation include timber extraction and logging for a range of luxury products or a source of energy, subsistence and commercial farming, roads and settlements and rock and mineral extraction.
What are five impacts of deforestation?
Impacts of deforestation include
habitat loss as biodiversity is lost when habitats are lost, soil erosion and desertification as forests reduce the impact of heavy rainfall on the ground which reduces soil erosion. Tree roots bind the soil in place and the layer of fallen leaves and branches protects the soil, overtime after deforestation the area that has once supported luxuriant growth may because a desert because of desertification, climate change as the permanent removal of trees leads to large quantities of carbon dioxide when burnt or decomposed and loss of biodiversity and genetic depletion as various species die or relocate when their habitat is destroyed leading to the loss of species containing potentially useful genes.
What are carbon sinks?
Carbon sinks are vegetated areas where the intake of carbon dioxide from the atmosphere in photosynthesis exceeds the output from respiration, so the net flow of carbon is from the atmosphere into plants. An example of these are growing forests.
What are carbon stores?
Carbon stores are mature vegetated areas where the intake of carbon dioxide from the atmosphere by photosynthesis equals its output from respiration so the mature plant stores carbon. An example of this is a mature forest.
What is the role of forests in the water cycle?
Role in the water cycle as forests add water to the atmosphere during transpiration, leading to the formation of clouds, eventually releasing it by precipitation. During deforestation, this process is reduced, and local droughts are caused in the area. Forest generate moisture in the atmosphere that can affect rainfall around the world.
What is the role of forests in preventing soil erosion?
Prevention of soil erosion as trees intercept rain, reducing heavy rainfall on the flood, debris such as tree leaves on the floor of the forest slows run off, roots of trees hold the soil in place and forests on the coast reduce soil erosion by absorbing energy from storms.
What is the role of forests for ecotourism?
Ecotourism is the responsible travel to a natural area that promotes conservation of the environment. Visitors travel with the main aim of appreciating its beauty. Ecotourism is both a reason to manage forests sustainably and a method by which this can be achieved, it may be mainly economic in focus, with success measured by income or focused on sustainability, with success measured by a limit on the number of visitors.
What is the role of forests for biodiversity as a genetic resource?
Biodiversity as a genetic resource as forests are vital for the lives of many animals, plants and other organisms because of the habitats they provide. These organisms in return represent a huge genetic resource as well as a source of food, medicine and raw materials for industry.
What are four ways to measure biodiversity in an ecosystem?
Pitfall traps, pooters, quadrats and transects
What are pitfall traps?
Pitfall traps are used to sample non-sedentary organisms such as insects. It consists of a jar sunk up to its rim in the soil, the jar may or may not be covered depending on the predicted likelihood of rainfall, traps should be inspected and emptied regularly, it can be used randomly or systematically, a drawback is that is measures the activity and number of the species.
What are pooters?
Pooters are sued to sample non-sedentary organisms such as insects. Insects in short vegetation or on trees are usually trapped in this net. For example, a pooter is used to transport the organisms from the nets or traps to a laboratory.
What are quadrats?
Quadrat is a frame of the known area placed on a part of the site to be samples. It is used to sample sedentary organisms such as plants. The number of organisms of the species is then counted, sometimes the percentage of the organisms in the quadrat is calculated.
What are transects?
Transect is a sampling method in which sampling devices are laid out along a line already placed across an area. It is used for sampling sedentary organisms such as plants and is an example of systematic sampling.
What are three advantages of quadrats?
Quick, inexpensive and portable
What are two disadvantages of quadrats?
Not always very accurate, unless many quadrats are placed the sample can be unintentionally biased
What are three advantages of transects?
Quick, inexpensive and portable
What is a disadvantage of transects?
Often used in inappropriate situations
What are two advantages of pitfall traps?
Inexpensive, easy set up and use
What are two disadvantages of pitfall traps?
Often kill the organism captured, may over sample or under sample
What is random sampling?
Random sampling is a sampling method in which the sampling device is placed using random tables or a dice role. It is used when two areas need to be compared.
What is systemic sampling?
Systematic sampling is a sampling method in which the sampling device is placed along a line or a predetermined pattern, usually a transect. It is used to check how the species change along a gradient in the environment.
What are twelve ways to manage biodiversity in an ecosystem?
Sustainable harvesting of wild plants and animal species, sustainably forestry, agroforestry, alley cropping, national parks, wildlife and ecological reserves, wildlife corridors, extractive reserves, world biosphere reserves, seed banks, zoos and captive breeding, and sustainable tourism and ecotourism.
What is sustainable harvesting of wild plant and animal species and how does it help to manage biodiversity in an ecosystem?
Sustainable harvesting of wild plant and animal species means to meet the needs of the present without denying the needs of future generations. Many plants have medicinal properties because of the secondary metabolites they produce which are organic compounds produced by bacteria, fungi or plants that are not directly involved in the normal growth, development or reproduction of the organisms. Wild plants are the preferred source as cultivated varieties only produce small or none of the chemicals used. Management plans to control the harvesting of wild-grown medicinal plants include assessing the abundance of the plant, investigating species growth rates, reproductive biology, impact of harvesting, assessing the yield that the wild population can sustain and details of how the harvesting should be monitored.
What is sustainable forestry and how does it help to manage biodiversity in an ecosystem?
Sustainably forestry is the removal of only mature trees of species that are valuable. Other species and immature trees of value species are left, allowing the forest to repair over. Non valued trees still provide habitat for many species and immature valued trees can be used years later.
What is agroforestry and how does it help to manage biodiversity in an ecosystem?
Agroforestry is a land management system in which crops are grown around trees. Trees enrich the soil when the leaves fall and provide food for animals, firewood for people and sometimes medicine. Tree roots bind the soil together and, in some cases, fix nitrogen, further enriching the soil. Farmer obtain food and milk from the farm, and their animals enrich the soil with manure.
This diagram shows part of the carbon cycle. State the processes at A, B and C (3)
A – combustion:
B – respiration;
C – photosynthesis;
State two reasons, other than soil erosion, why forests need to be conserved (2)
as a carbon, sink / store;
maintain biodiversity;
plants may be source of medicinal drugs / eq ;
for sustainability of supply of forest products / food;
The effectiveness of national parks as a method for conserving biodiversity depends on the
interactions shown in the diagram. Suggest reasons why (5)
all three interactions required for success;
tourists need to respect, wildlife / habitats / ecosystem;
employees / rangers / guides, needed to work in park;
residents need to manage resources sustainably;
visitors provide money for national park activities;
government(s) needed for, legislation / laws / regulations;
wildlife need to, live / breed / feed, in habitats;
people need to deal with invasive species;
reintroduce species from captive breeding;
control populations to protect habitats of different species;
habitats provide place for wildlife and people to live in;
habitats provide resources for people;
managed timber extraction;
medicinal plants;
genetic resources / gene bank;
Suggest reasons why Halley scientific research station in Antarctica is built on giant metal skis, with legs that can be adjusted (4)
easily moved;
height above ice can be increased;
legs can be removed / stops it getting buried / stops legs getting stuck / reduces land pollution;
increases surface area / stops sinking;
idea of durability or strength of metal;
Describe how the student can use a quadrat to record the number of different plant species (5)
max two from quadrats:
quadrat of stated dimensions, e.g. 1
m2;
quadrat placed at, regular intervals / stated intervals;
sample all (three) transects;
counting:
count the number of species (in the quadrat);
description of how to deal with plants partially in an quadrat;
recording:
record number in a table;
repeating:
repeat same investigation;
repeating on different days;
Explain the flow of energy through this food web (3)
energy transfers when organisms eaten / stated example of feeding from food web e.g. plant eaten by rabbit;
lost as heat;
idea of only 10% of energy passed between levels / 90% is lost;
lost through:
respiration;
digestion;
(excreted) waste (products);
movement;
death / decomposition;
maintaining body temperature / thermoregulation;
feeding / consumers do not consume the whole organism;
reproduction;
Explain why scientists are concerned about the impact of lionfish on the ecosystem of the area (4)
lionfish are inedible;
therefore nothing will feed on them (no predators);
eat large quantities;
impact on food web;
decrease in populations of small fish;
introduced/invasive species (to the Atlantic Ocean);
means competition to other (native) organisms;
lay large quantities of eggs;
large population increase;
Suggest reasons why using the data in the table is likely to give an underestimate of the total number of species in the 10km2 sand dune reserve (3)
the method only covers five (small) areas;
five transects are not representative;
lot of sand dune not sampled;
plants not evenly distributed;
longer transect needed (across whole area);
Explain the functions of the three main zones of a biosphere reserve (3)
Core area: monitoring / research activities / no settlements / protect the ecosystem;
Buffer zone: controlled / limited access for people / eco-tourism / recreation / research, / education and training / some
limited settlements / local tribes / communities ;
Transition area: research / tourism / recreation / greater settlements / controlled human activities e.g. sustainable farming;
Describe how the pitfall trap shown in the diagram is used to sample organisms (3)
glass jar buried in soil;
organisms, walk / fall / captured into trap;
tall/ smooth sides prevent organisms escaping;
cover prevents rain filling it up with water / excess heat / gives shade;
number of, organisms / species, counted / classified;
periodic sampling;
Suggest two limitations of using this pitfall trap to sample organisms (2)
can only catch organisms that crawl / move on surface;
some might fly out;
can only catch small organisms (less than 10cm);
organisms in the trap might eat each other;
glass jar does not allow water to drain out;
not representative of the whole population;
