Unit 2.1 & 2.2 Flashcards
Ecosystem
A community of interdependent organisms and the physical environment they interact
Made up of biotic and abiotic factors
Biotic components of ecosystem
anything that is living and any interactions between the living components
organisms and plants
- producers, consumers, decomposers
- predation, disease, compettion
Species
is a group of organisms with common characteristics that can interbreed to produce fertile offspring.
Population
is a group of individuals of the same species living in the same area at the same time.
Abiotic components
non living physical factors - temperature, sunlight PH, salinity, precipitation
Interact with biotic elements
habitat
the environment in which a species usually lives.
Niche and example
the role an organism plays and the position it holds in the environment. It includes all the interactions the organism has with the abiotic and biotic environment.
ex. Red eyed frog - carnivorous - prevents over populartion and are also source of food to other
Liming factor
resources in the environment that limit the growth, abundance and distribution of organisms/populations in an ecosystem. may be abiotic or biotic and they determine the carrying capacity
Carrying capacity
maximum number of individuals of a species that the environment can sustainably support in a given area.
Population growth curves
Predation
is where one organism (the predator) hunts and kills another (the prey) in order to provide it with the energy for survival and reproduction.
Predator prey relaionship
- Prey higher number than predators –> loss of enegry through food chain
- Populations peak out of sync
Parasitsm
is when an organism (the parasite) takes nutrients from another organism (the host).
Mutualism
Where two organisms of different species exist in a mutually beneficial relationship.
ex. Bacteria in the intestines of cows to facilitate digestion celliulose. Cows better digestion, bateria safe place to live
Competirion
When organisms compete for scarce resoyrces.
If there is not enough one species will experience lower growth rates and suvivral of both might be impossible which affects population dynamics
Photosyntheis and formula and purpose
the process that Primary producers undergo in most ecosystems to convert light energy into chemical energy
carbon dioxide + water = glucose + oxygen
Photosynthesis produces raw material for biomass production
Respiration, formula and implication
is the conversion of organic matter into carbon dioxide and water in all living organisms, releasing energy.
glucose+oxygen = carbon dioxide + water
Large amounts of enegry are released, increasing energy in the eco-system while mantaining it low on organsms
Trophic level
the position an organism (or group of organisms in a community) occupies in the food chain.
Food chain vs food web
Food chain
- simple single lines showing what eats what
- only one arrow
- only 1 TL for each organism
Food web
- internonnected food chains - complex
- many at different trophic levels
Food chain demomstrate 1st and 2nd law of thermo because
Energy is neither created nor destroyed (1st law) in the food chain and as energy passes along the food chain entropy increased (2nd law).
How much energy. passes from one trophc level to the next
10%
Ecological Pyramid
Trophic level in order - primary producers - quaternary consumers
flow of energy up the pyramid
length of bar proportional to what its showuing
Pyramids of numbers adv and disav
Shows number of organisms at each trophic level
Adv:
- non destructive method of data collection
- good for comparing changes over time
Disadv:
- does not take into consideration size of organism
- numebers may not be accurate
Pyramid of Biomass adv disv
A graphical representation of the amount of biomass at each trophic
adv; overcome problems of number pyramid
disadv
- measuriing parts that do not contribute
- must be extrapolated
- destructive methods
- seasonal changes may vary
Biomass
Biomass is the total amount of living matter in a given area so it represents the standing stock of energy storage at each trophic level
measured as dry weight
g m–2
Pyramid of productivity
refer to the flow of energy through a trophic level,
indicating the rate at which that stock/storage is being generated
J m-2 yr-1.
adv:
- most accurate
- rate of production over time
- compasirons allowed
disv:
- not esasy to collect data
- difficulut to assign trophic level
Bioaccumulation
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.
Bio magnification and accumulation DDT case studty solo leelo
Fast facts about DDT:
It is a persistent organic pollutant (POP).
It is stored in the fat cells of animals.
Fat-soluble toxins are a problem because they cannot be eliminated through sweating or urination so they stay in the body for a long time.
It has a half-life of 15 years, which means if 1 Kg of DDT is released into the environment 500 grams of it will still be there after 15 years.
It results in bioaccumulation and biomagnification.
DDT is sprayed on land to control malarial mosquitos, and whatever is sprayed on land ends up in nearby water bodies. The primary producers of the aquatic food chain are plankton and they essentially live in a dilute DDT soup. All the time they live in that soup they are absorbing and accumulating DDT (or mercury or any other such toxin). Just as phytoplankton absorb and accumulate DDT from the surrounding environment the herbivores ingest and accumulate DDT from their food source – the phytoplankton. This applies to any organisms in the polluted environment.
Bioaccumulation is not the worst of it. Due to the nature of the food chain and the loss of energy and biomass at every trophic level biomagnification becomes an issue. Let us turn the 10% law around a little. If each phytoplankton only passes on 10% of its energy that means (more or less) that the zooplankton must eat ten phytoplankton to get enough energy to live – this is not exactly true but it is better if the maths is simplified. As the zooplankton eats ten phytoplankton it picks up ten units of DDT too. The same rule passes up through the food chain and the DDT magnifies 10 fold every time. Small fish eat zooplankton - 10 × 10 = 100 units of DDT. Large fish eat small fish 10 × 100 = 1,000 and so on. So by the time you get to the top of the food chain there is a lot of DDT in the organisms and it has reached harmful levels. The impact of DDT is discussed in section DDT.
