Test 4: Ecology and Ecotoxicology Flashcards
What is a community?
It is a “group” formed when all the different populations of species share the same habitat.
When a group of organisms share an environment.
How do you measure biodiversity?
Species richness and relative abundance.
What is species richness?
It is the total number of species in a community.
What is relative abundance?
It is the number of species in relation to the total organisms in the community.
When is there a high biodiversity?
When the species richness is high and the relative abundance is similar (relatively equal).
What are interspecific interactions?
They are relationships between individuals of different species.
What are the types of interspecific interactions?
- Competition
- Predation (sub-set parasitism(symbiosis))
- Mutualism (symbiosis)
- Commensalism (symbiosis)
What is symbiosis?
It is close and often long-term interactions between 2 or more different biological species.
What is competition?
It is a relationship where different species compete for the same limited food resources.
Which type of species will profit the best from the available resources?
The species that can adapt.
What can strong competition limit?
Strong competition can limit the presence of a species.
What is predation?
It is when one species kills another for food (hunting). The predator feeds on the prey.
What is parasitism?
It is a relationship in which one species benefits while harming another.
What is commensalism?
It is a relationship in which one species benefits without helping or harming the other.
What is mutualism?
It is a relationship in which both species benefit.
What is a population?
It is a group of organisms of the same species living in a shared habitat (defined space) at a given point in time.
What is the population characterized by?
- Size
- Growth
- Density
- Distribution
What is population size?
It is the number of individuals in a population. It can increase, decrease or stay constant over time.
What are factors that affect population size?
- Natality
- Mortality
- Immigration
- Emigration
How do we estimate the size of a population?
- Counting
- Random Sampling (sample area)
- Mark and recapture
How to do to random sampling?
Divide areas of land into equal plots, count the number of individuals in each plot, calculate average, multiply by total area then divide by area per plot.
Average # of individuals / Area per plot = Total population / Total area
How to do mark and recapture?
Capture and mark, release, recapture. # marked in sample 1 (M) / Size of whole population (N) = # marked in sample 2 (r) / Total caught in sample 2 (n)
What is population growth?
It is the increase, decrease or consistency in the growth of a population.
When does the population increase?
When natality + immigration > mortality + emigration
When does the population decline?
When natality + immigration < mortality + emigration
When does the population size stay constant?
When natality + immigration = mortality + emigration
What affects population?
Time affects population.
What is carrying capacity?
It is when the resources in an area are limited there is a limited population that can be supported.
It is the maximum number of individuals that can be supported in a given area.
Population will grow over time, until carrying capacity is reached, once exceeded what will happen to the population?
The population will decline.
What are limiting factors? Give examples.
Factors that limit the growth and survival of a population.
Examples: Biotic and Abiotic factors.
What are biotic factors? Give examples.
They are living factors that can have an impact on (influence) a population.
Examples:
- Food - Humans
- Bacteria - Parasites
- Predation (predators) - Limited plants
What are abiotic factors? Give examples.
They are non-living ecological factors of physical or chemical nature that can affect (influence) a population.
Examples:
- Sunlight - Storms
- Atmospheric composition - Droughts
- pH - Floods
- Temperature - Volcanic activity
- Pheromones - Deforestation
- Water - Pollution
How to calculate population density?
D= number of individuals of a species (n) /
surface area or volume occupied (a or v)
What is population distribution?
It is the way in which individuals are spread out over a territory.
What is population density?
It is the number of individuals of a species counted divided by surface area or volume
What are the three ways in which individuals are spread out in a territory?
- Clumped
- Uniform
- Random
What is clumped distribution?
It is when individuals form clumps that improve chance of survival. The most common.
What is uniform distribution?
It is when individuals maintain an equal distance between each other, this indicates a strong competition for space and resources.
What is random distribution?
This occurs when there are the same conditions over a territory and a little competition between individuals, or when the conditions are just random. Spread out randomly. The least common.
What are important characteristics in the biological cycle and how do they vary?
- Frequency of reproduction
- Age of maturity
- Reproductive maturity
- Number of offspring
These characteristics vary by species.
How do the size of an organism relate to the number of offspring it produces?
Usually the larger the organism, the lower the number of offspring and the smaller the organism, the larger the number of offspring.
What is an ecosystem?
It’s a community of species interacting in a given area (habitat).
An area that contains living things interacting with one another and their non-living environment.
What is a micro-habitat? Give examples.
A small habitat. Tree stump, aquarium.
What is a macro-habitat? Give examples.
A big habitat. Caribbean ocean, African planes.
What are the characteristics of living things?
- Made out of cells
- Acquire and use energy
- Grow and develop
- Reproduce
- Respond and adapt to their environment (within reason)
What are trophic relationships?
The feeding relationships between organisms that eat and organisms that are eaten, represented by a food chain.
*From google
What are the three trophic levels?
- Producer
- Consumer
- Decomposer
What are food chains?
They are representations of the trophic relationships between different living things.
What are food webs?
They are a group of interrelated food chains.
Where do the arrows point in food chains and webs?
In the direction of the energy flow. (grass–> bunny)
What are ecological pyramids?
A representation of the flow of energy and matter in the form of a pyramid, in which each trophic level is represented by a rectangle whose size is proportional to the amount of biomass it has.
What is energy flow?
It is the flow of matter and energy that are transferred/transformed in a food chain.
What is biomass?
It is the mass of all the organic matter in an ecosystem. It represents the total mass of living matter in an area at any given time.
Why do both energy and biomass usually decrease with each trophic level?
Both energy and biomass usually decrease with each trophic level since organisms give off more energy to breathe, eat, reproduce, move, etc. while moving up. And going up the organisms get lighter because there are less of them, so lower biomass.
What do trophic levels affect?
Trophic levels affect relative abundance and population size for the whole ecosystem to remain in balance.
How much energy is transferred from one trophic level to the next?
10% of the energy is transferred.
Is the rainforest or the tundra more productive?
The rainforest because theres more rain (more water to make things grow) and it’s hotter (so more active, more things being produced).
What are producers?
They are autotrophs (produce their own food). They convert inorganic material into organic material using light (photosynthesis (producing sugar)).
What is cyanobacteria?
They were the first uni-cellular organisms to produce oxygen in Earth’s history.
What is primary productivity?
It’s the total quantity of new organic material made by the producers in an ecosystem over a certain period.
What does primary productivity depend on?
It depends on factors such as sunlight, carbon dioxide concentration, availability of nutrients, water and temperature.
What are consumers?
They are heterotrophs (they get their food from a variety of other living things).
What are the three levels of consumers?
- Primary consumers (herbivores): eat plants
- Secondary consumers… (carnivores): eat other consumers)
- Omnivores: eat from many levels, autotrophs, other consumers.
What are decomposers?
They eat dead organisms and waste, breaking it down into inorganic matter (respiration). They are connected to all the trophic levels.
What is chemical recycling?
It occurs when decomposers make inorganic matter available in an ecosystem by breaking down organic matter.
Where does chemical recycling occur?
At each trophic level in a food chain a certain amount of material is recycled by decomposers back into nutrients that producers can use.
What is an ecological disturbance?
It is an event that disrupts an ecosystem, that can lead to the reduction or elimination of organisms (or species) and change in the available resources.
What are the types of disturbances?
- Natural disturbances
- Human disturbances
What are natural disturbances? Give examples.
They are disturbances that occur due to environmental phenomena. Examples: - Storm - Fire - Flood
What are human disturbances? Give examples.
They are disturbances that are man made, the main form of ecological disturbance on Earth. Examples: - Oil spills - Deforestation - Nuclear meltdown
What is ecological succession?
The series of changes that occur over time in an ecosystem after a disturbance and that continue until the balance of the ecosystem is restored.
What is an ecological footprint?
The estimate of how much of the available resources we consume and how much waste we generate.
The measure of human demand on Earth’s ecosystems.
How to calculate ecological footprint?
Ecological footprint =
Land and water occupied
+ Land and water used to produce goods and services for a population
+ Land and water used to dispose of our waste
How to calculate Happy Planet Index?
Happy Planet Index =
Experienced well being X Life expectancy /
Ecological footprint
What is the relationship between the happy planet index and ecological footprint?
They are inversely proportional.
What is ecotoxicology?
It is the study of the toxic effects of pollutants.
What are contaminants?
They are any type of substance or radiation likely to cause harm to one or more ecosystems.
What are the classes of contaminants? Give examples.
- Inorganic contaminants: Lead, arsenic, mercury, nitrogen oxides, phosphorous
- Organic contaminants: Insecticides, pesticides
- Microbial contaminants: Viruses, pathogenic bacteria
- Radioactive contaminants: Uranium, plutonium
What is the toxicity threshold?
It is the amount of contaminant that will cause harm in an organism. The minimum level of concentration at which the contaminant causes harm.
What is toxicity?
It is the dosage that makes the poison.
It is the degree to which a contaminant can harm an organism.
What is the dosage dependant on?
Mass (concentration). amount / weight
What does the toxicity of each contaminant depend on?
- Concentration
- Type of organism (affect biochemistry)
- Duration of exposure
What is the lethal dose?
It is the amount of contaminant necessary to kill an organism in a single dose.
What is Lethal Dose Fifty (LD50)?
It is the dose that causes the death within 50% of individuals.
How do we estimate lethal dose and LD50 without killing?
Test at lower dosages. Use math projection.
Find slope = a/b ???
What is bioaccumulation?
It is the degree to which a toxin can accumulate in a living organism through inhalation, ingestion and/or dermal exposure. These contaminants resist natural degradation and cannot be eliminated.
It is the accumulation of a toxin in an organism over time.
What is bioconcentration?
Toxin is generally stored in the fat tissues of the consumer. The consumer consumes a lot of producers causing the concentration of the toxin to be higher in the consumer than in the producer and so on.
It is a situation in which the levels of a toxin in an organism exceed the levels of that toxin in the surrounding environment.
What is biomagnification?
It is the increase in concentration of a toxin as it passes through to higher trophic levels of a food web.
It is the situation in which levels of toxins increase the higher one moves up a food chain.
What is DDT and what is it used for?
It is a powerful insecticide used to reduce mosquitos and thus malaria transmission. (Now banned from use.)
What are the ecosystem impacts with using contaminants?
The problem is once the contaminants are in the ecosystem, they are difficult, if not impossible to remove.
What is bioremediation?
It is when we take certain species and add them to a region that has particular contaminants and have the species degrade the contaminants.
“Using a living organism to clean up the mess.”
What is eutrophication?
The enrichment of an ecosystem with chemicals nutrients.
What is phytoremediation?
It is the use of plants/producers to remediate an area.
How do wastewater treatments work?
The water starts at the top and goes through a system, then settles on the bottom. The water is being treated with chemicals to make it clean.
What is intraspecific competition?
Two individuals of the same species competing for the same food.
What is interspecific competition?
Two different species competing for the same food.
