Unit 2.1-2.3 (KOGNITY ONLY) Flashcards
Ecology
The study of interactions between organisms and the environment in which they live
Organism measures
How varied they are (diversity), where they are located (distribution), what they are (species), how many there are (population), and how they interact and adapt
An ecosystem is made up of
Biotic (living) and abiotic (non-living) components
All species have two binomial names, there
Part 1 is the genus, part 2 is specific to the species
Species each
Have a habitat and a niche even if they all live together
The niche of a species
What they do for a living
Carrying capacity
Max number of species that it can support at a given time
Ecosystem
Community of interdependent organisms and the physical element they interact with
Biotic component
Anything living and interactions between living components. This includes all the organisms (plants and animals), anything they consume or that consumes them, and human influences
Biotic component examples
Producers, consumers, decomposers, interactions between them
Producers
Plants that convert energy into matter
Consumers
Animals that eat plants or other animals
Decomposers
Organisms that breakdown waste into component parts for reuse
Interactions between living components
Predation, herbivory, parasitism, mutualism, disease, competition
Species
A group of organisms with common characteristics that can interbreed to produce fertile offspring
Population
A group of individuals of the same species living in the same area at the same time
Population example:
The Eurasian red squirrel - 23 subspecies across Europe and Siberia
The development of subspecies
The further apart the population, the less likely of interbreeding
Population determination factors
Births and immigration (growth), deaths and emigration (decline)
Population growth
Birth + immigration > deaths and emigration
Population decline
Births + immigration < deaths and emigration
Population dynamic equilibrium
Births + immigration = death and emigration
Abiotic components
Non living things - Influence living elements and operate as limiting factors - Biotic elements interact with abiotic elements
Abiotic component examples
Sunlight, pH, temperatures, salinity, precipitation
Ectotherms such as reptiles….
Rely on the environment to regulate their body temperature so this is a large factor of their distribution
All organisms have a temperature range….
Which they can live, and if the temperature deviates too much they will be stressed and may die
Water temperature influences….
The amount of oxygen the water contains and is vital to aquatic life
Sunlight and solar energy
The base of most food chains, creates photosythesis, enables plants to transform light energy into chemical energy
Sunlight has seasonal fluctuations, this affects….
Life cycles of plants and animals, length of growing season, mating cycles and more
Sunlight in aquatic systems
Water absorbs light, the deeper into the water, the less light available, so photosynthesis is not possible 200m down. There is zonation 1000m down where there is no light
Water in an ecosystem….
Water arrives to an ecosystem as precipitation, groundwater, flow, or overland flow. It is an ingredient in photosynthesis and the medium in which life’s processes take place
Organisms and water
Different organisms have different levels of tolerance to lack of water. Eg: deserts. Animals can become weak and confused and will die if water is scarce for too long.
PH in an ecosystem
All organisms have a tolerance range in which they thrive. If the PH doesn’t remain balanced, the ecosystem will break down (eg: freshwater, soil microbes)
Salinity in an ecosystem
Like all abiotic factors, organisms have a range of tolerance to salinity. (Impact on soil which causes agricultural issues if too high) aquatic ecosystems are sensitive to changes
Habitat
Environment around an organism which is where they live, it provides physical and biological resources for that organism. It may not be a distinct location (parasite and host’s body)
Physical habitat characteristics:
Soil, moisture, temperature, sunlight
Biological environment of habitats”
Food, mate, predators
Niche
A set of abiotic and biotic convictions and resources to which an organism or population responds. The smallest unit of the habitat, how an organism fits into an ecosystem, where it lives, what it does, how it survives and reproduces
Example of a niche (red-eyed tree frog)
Carnivore, eater of moths, flies, crickets, and smaller frogs to prevent overpopulation. Provider of food for bats, birds, spiders, and snakes
No two species have the same….
Niche at the same time or location (if many species live together, they still have different needs) eg: diet
Fundamental niche
The full range of conditions and resources in which as species could survives and reproduce (tolerance range for abiotic factor’s in an organism’s environment)
Realised Niche
The actual conditions and resources in which a species exists due to biotic interactions (the part of the fundamental niche occupied by the species)
Limiting factors
Resources in the environment that limit the growth, abundance, and distributions of organisms in an ecosystem
Density dependent limiting factors
Affect the population when it reaches a certain density. They include competition, disease, parasitism and predation - they tend to be biotic factors. Disease spreads rapidly when there are many organisms for it to spread to
Density independent limiting factors
Control population no matter the density. Include sunlight, temperature, water, and natural disasters. High or low, organisms still need a particular temperature, amount of sunlight and water
Changes in population in response to abiotic or biotic factors
Can be represented as J and S shaped curves
J shaped curve shows:
Exponential population growth under ideal conditions with plenty of resources and limited competition. Population grows until environmental resistance take effect (organisms using all resources making population crash). Organisms following this will show great fluctuation and a “boom and bust” in pop. numbers
S shaped curve
Likely if resources are limited, limiting factors. Exponential growth only posible for a short period of time as resources are depleted as population grows. When it slows it will plateau off
Interaction among organisms….
Relate population size and impact the balance of the food web
Predation
One organism (predator) hunts and kills another (the prey) in order to provide it with the energy for survival and reproduction
Predation impact
Only beneficial to the predator, however, both populations are kept in balance
Herbivory
Consumption of plant material by an animal (herbivores)
Herbivory impact
Plants have defence mechanisms which makes eating painful for herbivores, some are toxic to the herbivore. So animals tend to add variation to their diet, or build up a tolerance
Parasitism
An organism (the parasite) takes nutrients from other organisms (the host)
Parasites
May live outside the host, or inside the host. It is not beneficial for it to kill the host, as it loses it’s habitat. As the population increases, the host will die. Parasite populations outnumber the host because the parasites are significantly smaller
Mutualism
Where two organisms of different species exist in a mutually beneficial relationship. Sometimes if the species of one increases, so will the other
Mutualism is a form of
“Symbiosis” which is a form of living together and there are a range of relationships created by it, amongst different organisms. It is a key process of an ecosystem (eg: 50% of terrestrial plants rely on fingí to absorb inorganic compounds from their roots)
Examples of mutualism
Sea anemones and clown fish - the fish provide food, anemones’ tentacles keep the fish away from predators. Oxpecker bird eats ticks off of zebras, buffaloes and rhinos, so the oxpecker can eat and the mammal is rid of the ticks
Disease
Departure from the normal state of functioning of any living organism, which can effect the whole body or just part of it. Signs and symptoms may be the result of environmental events, genetic defects or a combination. In serious cases, it can kill a population
Disease examples:
Ebola kills endangered gorillas and chimps, a major effect on already deleted populations. Anthrax killed 90% of Herbivores in Zimbabwe’s Malilangwe wildlife reserve (Tasmanian devil tumour)
Disease Impacts
Disease in normal populations can be devastating but catastrophic in endangered
Competition
Where organisms compete for a resource that is limited in supply (food, water, mates, habitat, etc) The resource must be limited for it to occur, there is no need if it is plentiful, causing a population j shaped curve. Unlimited resources are rare so competition is important so population will be an s shaped curve
Intraspecific competition
Member of the sam species compete for a limited resource. Most species will demonstrate this type of competition depending on the environment they are in
Interspecific compeition
Members of different species compete for a resource they both need. Resources fought over will be the same as in intraspecific except for mates and maybe habitat. Members of different species may not compete for mates or habitats since they are different
Interspecific competition impact
If there is not enough of the resource then maybe both species will experience lower growth and survival, or if two species feed on the same thing, a larger animal would steal from a smaller (cheetahs and lions)
Intraspecific competition impact….
Interspecific It has more impact on species survival and population than intraspecific. If members of the same species are fighting for the same thing, there is likely to only be a slight drop as weaker members of the same species are out competed
Biomes
A collection of ecosystems
As solar energy enters the system….
Plants use the light energy for photosynthesis which combines inorganic substances to transform them into organic matter. Once there is organic matter, the chemical energy can flow through the nutrients cycle
Respiration reverses….
Photosynthesis
Food webs and food chains
Establish links between organisms that feed on each other, to show feeding relationships
Ecosystem
A community of interdependent organisms and the physical environment they interact with. Includes the abiotic components
Community
A group of populations living and interacting together in a common habitat - the living components that interact with a habitat
Producers
Convert inorganic compounds into food - they are known as autotrophs or self feeders, they obtain food by making it themselves. They are the base of the food chain, referred to as primary producers
Primary producer examples
Usually green plants that manufacture their own food through photosynthesis, they take nutrients from soil and use solar energy to change light energy into chemical energy
If plants do not grow on soil, they may grow on….
Rock surfaces (beginning of succession), dead organic matter (fungi grow and start decomposing), other plants (orchids grow on trees)
Roles of plants in an ecosystem
Provide food for all other life on earth, regulate the hydrological cycle by taking and releasing water, maintain balance of gases by absorbing C02 and releasing oxygen, roots help bind soil reducing erosion, provide habitats for many animals
Chemosynthesis
A small percentage of primary production is provided by this, certain bacteria and organisms called archaea take energy released by inorganic chemical reactions to make sugar. This happens in he deep ocean hydrothermal vents, and in hot springs
Consumers
Also known as heterotrophs - other feeders, they can’t make their own food, so must consume other organisms
How Consumers derive their energy and nutrients:
Herbivores east just plants (leaves, fruit, nuts, wood, stems, flowers) - Capybara, carnivores only eat meat (African lions), omnivores eat both plants and animals (red panda)
Decomposers (detritivores)
Clean ecosystems by obtaining energy and nutrients from waste, dead plants and animals.
Detritivores
They are the first stage of the decomposition cycle by consuming detritus to get nutrients - (plant and animal parts/feces) Such as worms, ingest lumps of matter and pass them through to be dealt with by decomposers
Whilst energy flows through the ecosystem….
Nutrients cycle around it - which is why decomposers and detritivores are important
Decomposers examples
Bacteria and fungi, absorb and metabolise waste and dead matter on a molecular level and release as inorganic chemicals to be recycled by plants
Decomposers and detritivores are vital since they:
Clear dead bodies, prevent disease spreading by clearing, facilitate continued functioning by releasing nutrients that were stuck in organic matter
Green plants
Take light energy from the sun, and makes chemical energy
Trophic levels
Position an organism occupies in the food train
T4 is usually the highest tropic level….
Due to significant energy loss between each level
The number of steps an organism is from the start of the food chain
Indicates its tropic level
Flow of energy in the food chain is…
In the direction of the arrows and points where the energy is not where it has come from
Food chains demonstrate the….
First and second law of thermodynamics
1st law of thermodynamics
Energy is neither created or destroyed
2nd law thermodynamics
As energy passes, entropy increased
Energy enters the food chain as
Light energy, and transforms to chemical energy through chemical bonds in organic matter, which is what passes through the chain
If something goes in and out as organic matter
It is a transfer
Transformation in the food chain
Chemical bonds in food are broken and used for movement of energy transformed into heat - the least useful energy since it dissipates into the surrounding environment
Only 10% of energy
Moves from one trophic level to the next
Ecological pyramids
Show feeding relationships, are quantitative models to show information about organisms at each tropic level, there are 3 pyramids types. They always show the levels in the same order, flow of energy is up through the pyramid, and the length of the abr is proportional to the variable it shoes
Pyramid of numbers
Shows number of organisms at each level, the unit is whole numbers
Advantages of Pyramid of numbers
Non-destructive method of data collection, good for comparing changes in an ecosystem over time
Disadvantages pyramid of numbers
All organisms are included regardless of size, it can be hard to draw and accurate representation if numbers are so big, does not allow for juveniles or immature forms of the species (they may look very different)
Gm^-2 is the same as
G/m^2
Pyramid of biomass
Shows the biomass at each tropic level, which is the amount of living matter in a given area - the standing stock of energy storage at each level. It is measured in mass per unit of area or g/m^2 (grams per m squared) If it is looking at energy storage, the units are joules
Biomass is measured as….
Dry weight, this eliminates variation in water content between organisms. To find out the biomass, a sample is collected, dried and then weighed. This is destructive and unacceptable if you are dealing with animals
Advantages Pyramids of biomass
Overcomes problems of counting from the pyramid of numbers
Disadvantages pyramid of biomass
Only samples, meaning inaccuracy, methods of collection are unethical, seasonal variation of ecosystems making it unreliable, whole organism is measured including body parts of animals that so not contribute energy to the feeding processes, not all organisms have the same calorific value - especially dat in animals
Pyramid of productivity (energy)
Fixes up disadvantages of the other pyramids. This shows energy over a period of time, each bar represents energy generated and available as food, units are given as energy or mass per unit area per unit of time - joules per m squared per year (J m^-2 yr^-1)
Unlike other pyramids, the pyramid of productivity….
In a healthy ecosystem, is always pyramid shaped, sue to the 10% rule
Advantages pyramid of productivity
Most accurate as they show actual energy and rate of production over a period of time, ecosystems can be compared, solar input can be added to the model
Disadvantages pyramid of productivity
Data collection not east as you need to know the rate of biomass production over time, species can be difficult to assign to a level (in all pyramids) as shown in food webs
In aquatic food chains
There are 6-7 tropic levels
Why there are more trophic levels in aquatic food chains:
Starts with smaller organisms at the base, so lower levels are occupied by tiny plants and animals (microscopic phytoplankton), less biomass is taken up in skeletal formation so there is less waste and greater potential for longer chains. The water supports the wight of the animals so more assimilated energy goes to build muscle that can be passed (see source)
Downside of aquatic food chains
Less light gets through to primary consumers since it is absorbed or reflected by the water
Toxins in the food chain
May be natural or man made. Heavy metals and organic pollutants are the main problems since these toxins are relatively new to organisms who do not have capacity to eliminate them from their bodies
Bioaccumulation
Is the increase in the concentration of a pollutant in an organism as it absorbs or it ingests it from its environment
Biomagnification
The increase in the concentration of the pollutant as it moves up through the food chain
The amount of sunlight that enters an ecosystem is….
Very high - it provides a vast amount of the required energy
Geothermal energy
Heat, thermal energy, another source of energy for ecosystems which is also used in chemosynthesis. It is found in rocks and fluids in the earth’s crust. Energy in some food chains is geo thermal (see source: it is likely within the earth’s mantle there is a molten state providing heat to the surface)
When the sun’s energy reaches the earth’s surface
About half is visible light, with 40% infrared, and a small percentage of ultraviolet causing sun tan / buen depending on length of exposure. This is higher at the outer edge of the atmosphere, reducing as it passes through the ozone layer
Human impacts carbon cycle:
Extract/burning fossil fuels which release carbon from storage, deforestation, etc
Humans impacting energy flows:
Agricultural practices, alter the flow of matter locally, plant crops that have the best productivity take nutrients from the soil and grow. The crops are harvested and nutrients are removed to feed animals and humans in another system
Once solar energy enters the biosphere:
It can be used by plants to produce matter in form of biomass. Then this moves through food chains, and energy eventually passes back to the atmosphere as heat while matter is recycled
Productivity
The rate at which plants and animals lat down biomass.
Primary productivity is from….
Plants
Secondary productivity is from….
Animals
Solar radiation that reaches earth
The solar constant - the average amount of energy received by the atmosphere when the sun is at its mean distance from earth. This varies by time of year and the location relative to the equator
Equatorial areas receive….
More solar radiation
The solar constant approx.
1,370 watts per m square or 1,370 joules per second
Only half of solar radiation
Makes it through the atmosphere to the earth’s surface
Small particles and gases in the atmosphere
Scatter solar radiation in random directions which sometimes go to space. The wavelength of light most easily scattered is blue, which is why the sky is blue.
The most reflective aspects of our atmosphere:
Clouds, which reflect between 40-90% of incoming light
The reflectivity of a surface is called….
Albedo: dark colours have low albedo whilst light colours have a higher one. Albedo may be expressed as a percentage or decimal: (EG: clouds = 40% or 0.4)
Scattering and reflection counts for….
30% of incoming solar radiation, with atmospheric gases and particles absorb another 19%
Absorption
Where light energy is retained by the substance and transformed into heat. A large percentage is in the stratosphere where formation of ozone requires ultraviolet, leaving 51% of solar energy to the surface of the earth
51% of solar energy
Reaches the earth’s surface - some of this is available to ecosystems for photosynthesis, some is reflected back into space as long-wave heat energy
Albedo is the….
Reflectivity of a surface
Net primary productivity =
Gross primary productivity - respiratory losses
Gross
Total amount of products made in Ecosystems that would be the total amount of biomass made
Net
What is leftover after losses - ecosystems losses include respiration and fecal loss
Gross or net productivity can be….
Primary or secondary
Productivity will be EITHER….
Net or Gross
Gross Primary productivity
All biomass produced by primary producers in a given amount of time (pre respiration) This is hard to measure since the products of photosynthesis are used in respiration and repair
Net primary productivity
The usable biomass in an ecosystem, some which will be used as growth and some will be consumed by herbivores, It is not all that efficient. Not all biomes are equal which influences this
NPP on land based ecosystems
Are greatest around the equator where temps, sunlight, and precipitation levels are higher. They are lowest in hot, dry climates where deserts are located. In oceans, light and nutrients are limiting factors and mx levels are near coastlines where upwellings enhance nutrients
Gross secondary productivity = (assimilation)
Food eaten - fecal loss (shown as g m^-2 or J m^-2 yr ^-1)
Energy flows through ecosystems
In one direction - from high quality, low entropy, to the opposite
Cycles
Pass along the various trophic levels before breaking down and starting again
Net secondary productivity =
GSP - respiratory losses OR Food eaten - feces - respiratory
Secondary productivity can also be
Gross or net - and is measured for a whole tropic level
GSP represents
The total amount of energy or biomass assimilated by consumers, gross is not a very useful value as we don’t actually see it within the ecosystem 90% of what is assimilated by a consumer is actually used in respiration to release energy for life processes of far more use is NSP
NSP is….
What is left at the end of all processes for animal growth EG: to make new muscle
Sustainable yield
The amount of biomass that can be extracted without reducing natural capital of the ecosystem
Ecosystems are less productive
At certain times of year - (cold seasons), life style stages - (younger organisms have higher growth rates), they have been hit by disease, fire damage
Biomass is….
A store of chemical energy that is passed from one trophic level to the next before being converted into biomass of secondary producers - this has a poor efficiency and much chemical energy becomes heat energy
