Topic 1.5 Populations and Ecosystems (Ecosystems and Succession) Flashcards
Define the term ‘ecosystem’. A community comprises many _____ who live and _____ together. The interactions of organisms with each other as well as the _____ components of their environment. Examples of these ______ components/factors are: ____, _____, & _____. How are the abiotic and biotic factors of an ecosystem linked (2 things - think about energy and cycles of WHAT…)?
a) An ECOSYSTEM is a characteristic COMMUNITY in which the species that comprise the community are INTERDEPENDENT on each other. The interdependent species of the community also INTERACT with the abiotic factors/components of their habitat/environment.
b) A community comprises many SPECIES who live and INTERACT together. The interaction of organisms with each other as well as the ABIOTIC components of their habitat/environment in what is known as the ECOSYSTEM.
c) Examples of ABIOTC factors: air, water and soil.
d) Abiotic and biotic factors of an ecosystem are linked via energy flow systems and the CYCLING of nutrients.
Energy & Ecosystems - What is ‘energy’ (think about physics)? NO changes can occur until energy WHAT occur? The functioning of the ECOSYSTEM as a result of that can be thought of as a series of ENERGY _____, in which energy flows through the components of the ecosystem. However, their are laws/rules that govern these energy flows called the ‘Laws of ________’? Think about heat and energy…
a) Energy is the ability to do ‘work’ - it’s the force that causes things to move.
b) No changes can occur until ENERGY CHANGES occur…
c) ENERGY CHANGES
d) ‘Laws of Thermodynamics’
The energy that supports ecosystems comes mainly from where? The energy emitted from this PLACE is incorporated into plants by the process of WHAT? ENERGY also comes from _____ reactions - this is called WHAT?
a) The SUN
b) PHOTOSYNTHESIS
c) CHEMICAL reactions - CHEMOSYNTHESIS - i.e. the energy released as a result of chemical reactions.
BIOTIC components of ecosystems - HABITATS.
What is a ‘habitat’? A habitat may not always be a WHAT area? But instead habitats may be found in parts/areas of a living organism such as WHAT place in the human gut (name the tube that connects the stomach and is the first part of the small intestine) where a tapeworm can grow…?
What is a ‘microhabitat’ - think of the a cabbage looper (type of organisms called a morth larva) that feed on the bottom of a cabbage but NOT the top part of it…
a) A habitat is an environmental area (e.g. a fresh water stream) that is inhabited by LIVING organisms. The place where living organisms LIVE.
b) Habitats are NOT always found in GEOGRAPHICAL areas like the desert. They can be found in parts of another organism. In humans the DUODENUM can be home to tapeworms.
c) Micro habitats are area that differs from its surroundings with features that make it more suitable for certain species like the bottom of a cabbage for the cabbage looper.
BIOTIC components of ecosystems - COMMUNITIES.
What is a ‘communtiy’? First think about populations. Scales from there…
a) Members of ONE type of species interact with each other and form a POPULATION. Populations then interact with one another to form a COMMUNITY.
BIOTIC components of ecosystems - BIOMASS TRANSFER.
What is the ultimate SOURCE of energy for MOST (not ALL - be careful) ecosystems? What do photosynthetic organisms do with photonic energy in sunlight? Think about a transducer and the roles of pigments in photosystems. The WHAT energy formed by the pigments is transfered to other WHAT?
The energy recieved by a TROPHIC level contributes to its WHAT mass? What is the ‘trophic level’ & what is ‘biomass’? Food chains can be thought of as doing WHAT to biomass?
a) The SUN. Photosynthetic organisms contain photosynthetic pigments who transdue the photons in light into chemical energy passed on to other organisms.
b) Biomass. Trophic level = FEEDING levels - stages/levels of the food chain.
c) Biomass = the mass of the BIOLOGICAL material within a living organism or recently living organism.
d) Food chains can essentially be thought of as the transfer of biomass within an organism.
BIOTIC components of ecosystems - FOOD CHAINS.
1. What major organism incorporate the sun’s light energy into WHAT which is an umbrella term for sugars - there are two other major organisms who harness the sun’s energy so name them. ONE of these organisms is known as WHAT in the food chain? They are thus called an WHAT source. The ‘WHAT’ source is ‘food’ for other organisms…? What do these major organisms do to photonic energy? Which allows them to synthesise WHAT from inorganic compounds of photosynthesis - the solar energy absorbed is incorporated into them…
- What are ‘Herbivores’ and what are they classified as in the food chain? What are ‘Carnivores’? What are ‘secondary consumers’? What are ‘teritary’ consumers and what are ‘high consumers’ - these consumers are the located at the 5th trophic level called? Energy is passed on to the next trophic level as each trophic level feeds.
- a) Green plants, cyanobacteria and protoctista. Green plants incorporate the energy derived from solar energy into CARBOHYDRATES.
b) Green plants are calle PRODUCERS.
c) They’re known as ‘energy producers’ for the food chain as they themselves are an energy source in the form of FOOD for other organims called the PRIMARY consumers - i.e the herbivores who ONLY feed on plant material for a source of energy.
d) These 3 major organisms (green plants, cyanobacteria and protoctista) all transduce solar energy into chemical energy allowing them to synthesise carbohydrates/sugars. - a) Herbivores are after producers and they’re called secondary consumers. Herbivores consume producers who are the energy producers in a food chain.
b) Carnivores consume mostly meat and flesh.
c) After secondary consumers are the teritary consumers.
d) The final and 5th level of the trophic level is home to the quaternary consumers.
DECOMPOSITION.
When producers die, energy remains in the WHAT compounds of which allows energy to be obtained by the organism - (think about glycogen and what it does to energy)?
What are ‘saprobionts’? Remember from Y12 C2 that you have autophic organisms, heterotrophic and saprobionts. Linking to the definition of what saprobionts do, can you see how they contribute to the recycling of nutrients?
What is the difference between a detritivore and a decomposer (think about where they get their nutrients from)? Decomposers do what to the process STARTED by detritivores.
a) Organic compounds.
b) Saprobionst are organisms who derive their energy for growth from dead or decyaing matter.
c) Detritivores such as earthworms feed on SMALL fragments of organic debris - detritus, remains of dead organisms and fallen leaves.
d) decomposers FINISH the job (decomposition) started by detritivores by otaining their nutrients from dead organisms and animal waste (e.g. faecal matter).
Therefore, both detritivores and decomposer are saprobionts as they derive their energy for growth from dead or decaying matter!
Assessing the length of food chains.
A food web illustrates how organisms in a WHAT interact with each other through the WHAT they eat. SHowcase the linear food chain and highlight the trophic level. At what points on the linear food web is energy LOST?
Why can tropical food impact the length of the food chain? What about arctic food chains?
Efficiency of energy transfer can make the food chain longer or shorter? Predator and prey numbers can fluctuate so thier relative abundance can cause food chains to be?
a) A food web illustrates how organisms in a community interact with each other thorugh the food they eat.
b) Producer (1st trophic level) –> Primary consumer (2nd trophic level) –> Secondary consumer (3rd trophic level) –> teritary consumer (4th trophic level) –> Quaternary consumer (5th trophic level).
c) Energy is lost at each point LINK in the food chain - i.e. at each transfer.
d) The more energy that enters the first trophic level means more energy is fixed by photosynthesis. Tropical plants obtain HIGH amounts of light all year round. Arctic food chains are shorter due to the opposite reason!
e) Longer
f) Shorter
Photosynthetic efficiency:
Leaves can absorb more energy at a given light intensity if they are thicker, have a thin cuticle, more chloroplasts & chlorophyll as well as having more grana in the chlorophyll.
Where does the energy flowing through a food chain origionate? Why might 60% of the total light that falls of a plant not be absorbed - 3 reasons (there is a solution to one of the problems in the above sentence)?
GIve the formula for PE (photosynthetic efficiency). Give 1 thing apart from environmental factors that can imapct PE…
a) From the sun.
b) 1. light penetrates the leaf and goes through the leaf 2. Wrong wavelength of light thus the pigments don’t absorb 3. light is REFLECTED of the surface of the leaf. These 3 form the various fates of solar energy.
c) PE (%) = Quatity of light energy incorporated INTO product/ Quatity of light energy that falls onto the plant x 100
d) Genetic factors.
a) What is GPP? Define it and what does it stand for?
b) A substancial proportion of GPP is released by the WHAT of the plant?
c) What is NPP? Define it and what does it stand for? NPP is available to who down the line?
d) What does ‘biomass’ mean?
e) What is the formula for NPP? Your GPP calculations should be around __% -__% and your NPP calculations should be around __% - __%
a) Gross Primary Product - This is the rate of production of chemical energy in organic molecules via photosynthesis in a given area in a given time.
b) A substancial proportion of GPP is released by respiration the plant must complete in order to fuel biosynthesis.
c) Net Primary Productivity - This is the energy that is incorporated into the plant’s biomass which is then available to primary consumers.
d) Biomass is the mass of the biological material within an organism.
e) NPP = GPP - Respiration (GPP calculations should be around 0.2-2% and NPP calculations should be around 0.1%-1%)
a) What is the meaning of ‘primary productivity’?
b) What is the meaning of ‘secondary productivity’?
c) As energy is passed along a food chain, WHAT happens to it (i.e. the energy)?
a) Primary Productivity = This is the rate at which producers convert energy to biomass.
b) Secondary Productivity = This is the rate at which consumers incorporate the accumilated biomass into their tissues / cell.
c) There is a loss of energy as energy moves up the trophic levels.
a) We’ve established that as energy moves up the trophic level energy is lost. There are 3 ways energy is lost. List each and explain.
b) What are the relative % of conversion between herbivores and carnivores?
a)
1. There is still energy within the egested material!
Cows feed on plant material that contains cellulose which is digested by the mutulastic bacteria that live within the cow’s gut. The remains are passed out of the body in the form of faecal matter. However, despite being lost from the food chain, that energy is NOT lost from the ecosystem as decomposers feed upon it.
2. Energy is lost through processes fuelled by the energy generated in respiration, including muscle contraction.
3. Energy remains in molecules in parts of an animal that may not be eaten - for example: bones, fur and horns.
b) Herbivores, the primary consumer, have a conversion efficiency of about 10%. Carnivores have a conversion of about 20% because their diet is protein rich - diestion is easier!
a) What is the ‘efficiency of energy transfer’ equation?
a) Efficiency of Energy Transfer = energy incorporated into biomass after transfer/ energy available in biomass before transfer x 100%
a) What is an ecological pyramid? There are 3 types we look at. Name each and explain them.
b) What is one flaw of ecological pyramids?
a) An ecological pyramid is a DIAGRAM that shows particular features of each trophic level in an ecosystem.
There are 3 types of ecological pyramids each differing due to the information that is displayed at each trophic level.
1. The pyramid of numbers - measures the sizes of all the animals within each trophic level.
2. The pyramid of energy - showcases the energy transfer between trophic levels. As energy decreases up the chain the bars decrease in their size.
3. The pyramid of biomass - showcases the energy passing through an ecosystem. Essentially, the energy making up an individual’s biomass (the NPP value therefore…)
b) Ecological pyramids don’t take into account that some organims can exist/operate at two different trophic levels. E.g humans - majority are omnivores.
a) What are 3 problems with the pyramid of biomass?
a)
1. Difficult to measure accurately since the entire structure of the organism must be accounted for (including the root of a plant e.g.).
2. They don’t indicate productivity or the amount of energy flowing through an ecosystem.
3. A trophic level may seem to contribute more to the NEXT trophic level but this isn’t true because remember that not all of the body is eaten by a carnivore for example. The bones aren’t consumed - they contain energy. The energy in these structures do NOT get trasnferred to the next trophic level - therefore the pyramid of biomass can be a bit mis-leading in that sense!
a) Ecosystems are described as WHAT that means they’re susceptible to change?
b) What is the meaning of ‘succession’?
c) What is the meaning of ‘climax community’?
d) What is the meaning of ‘primary succession’?
a) They’re dynamic!
b) Succession = The change in structure and species composition of a community over time.
c) Climax Community = A stable, self-sustaining community that has reached eqm. with its environment, and NO further change occurs. E.g. A mature woodland.
d) Primary succession is the series of changes in structure and species composition of a communtiy over time in an area that has NOT previously been colonised. E.g. a bare rock. A community is the interaction between different species living in the same habitat.
a) The sequence of communities, with different species and structures, is called a WHAT? What are they called in DRY environments?
a) The sequence of communities, with different species and structures, is called a SERE. A sere in a DRY environment is called a XEROSERE.
a) In the UK, the most recent ice age lasted from about 110,000 - 12000 years ago. Bare rock eroded by receding ice has undergone a WHAT succession - explain why it is this type of succession specifically… It is now primarily decidious forest.
b) Following on from ‘a’, explain the step-by-step process that led to the climax community, the decidious forest. There are 6 steps.
Lastly, explain the 3 features of a climax communtiy…
a) Bare rock eroded by receding ice has undergone a XEROSERE succesion. It’s xerosere succession because the bare rock is a dry envirnoment.
b)
1. The first organisms to colonise the bare rock are ALGAE and LICHENS. The first organisms are described as PIONEER specices because they (these species) are the first to COLONISE a new area.
2. The constant weathering of the rock paired with the erosion led by the LICHENS as well as the accumilation of DOM (dead organic matter) leads to the formation of a primative soil (essentially, soil in its early stages of formation).
3. Wind-blown spores allow mosses to flourish/grow and as the soil develops, grasses and other small herbacious plants outcomete the mosses and they (the grass and herbacious plants) become established. Well-dispersed species who make LOTS of seeds are favoured.
4. Tall grasses allow shade TOLERANT plants to exist/established and the communtiy becomes more COMPLEX. This is an example of natura selection.
5. As plants and animals die out and decay, the soil becomes THICKER, with more minerals. The greater the quantity of humus the greater the soil’s ability to retain water. As the soil builds up, deep-rooted plants become favoured and eventually outcompete the herbacious plants.
6. The soil continues to DEEPEN and increase in minerals and humus. Over a very large period of time, large trees begin to outcompete shrubs and smaller trees. Those tall trees become established. Eventually, the CLIMAX COMMUNITY is reached.
The climax community has
1. A greater species diversity
2. More complex food web
3. Dominated by long-living plants.
a) What is ‘secondary succession’?
b) What 3 things about SOIL determine the type of species that shall colonise a particular area?
a) Secondary succesion is the changes to a community following a calamity/disaster that disturbs and damages an already colonised habitat (colonised is essentially a KEY word here). Examples of disturbances include wild-fires.
b) The area rapidly becomes recolonised by a succession of organisms. However, the type of species depends on the CONDITIONS of the soil in the area being disscussed. Things such as the soil’s thickness, mineral density and humus content are determining factors of which type of species shall colonise the area. Succession is RAPID.
a) Disclimax - This occurs due to the interferference of humans and can impact the development of the climax community!
1. Grazing by sheep and cattle maintains grasslands and prevents the formation of WHAT and WHAT of a normal succession from growing.
2. Farming of a land removes all except deliberately introduced species and great effort is put into their maintainance.
3. Deforestation removes a communtiy of larger trees, and smaller trees may be replanted.
a) Formation of shrubs and trees.
We shall now concentrate on the factors of succession.
a) Immigration can impact succesion. What is ‘immigration’?
b) Competition can impact succession. In all communities, organisms compete for survival. Plants and Animals compete for different things.
c) There are two types of competition. Name and define both types.
d) What is a ‘niche’?
a) Immigration is the arrival of new spores, seeds and animals vital for succesion to progress. The immigration of non-native species can alter the community and the soil too.
c)
1. Intra-specific competition = competition between individuals of the SAME species. This type of competition is DENSITY-DEPENDENT because as the population increases competition actually RISES! Looking at genetics, those organisms with alleles that make them best suited to the environment reproduce more SUCCESSFULLY.
2. Inter-specific competition = competition between individuals belonging to different species. For example, different species of fish compete for dissoled O2 within the water.
d) A ‘niche’ is a role and position a specie has in its own environment, including all interactions with the biotic and abiotic elements of the environment.
We shall now delve into the last section, FACILITATION’.
a) What is symbiosis? There is a range of interdependence between the individuals of a community. In some cases, the interdependence can be LONG-term, and in some cases it can be SHORT-term!
b) What is the defenition of ‘mutualism’?
e) What is commenalism and what is a really simple example involving a squirrel and an oak tree?
a) Symbiosis is the ASSOCIATION between individuals of two species.
b) Mutualism - This is the interaction between organisms of two differing species from which both derive a BENEFIT.
c) Commenalism is the interaction between organisms of two species from which one benefits and the other doesn’t feel any effect. This is commenalism. E.g. A squirrel can utilise and oak tree by seeking shelter. Although the squirrel recieves a benefit, the oak tree is left unaffected.
