5. On the Wild Side (1) Flashcards
5.1 - 5.11 ecosystems and energy transfer
Habitat
Where an organism lives
Population
All the individuals of one species living in a habitat
Size of population = …?
abundance of a species in a habitat
Exact location of a population =…?
Species distribution
Ecosystem
a community and its interactions with the non-living parts of its habitat
Community
multiple populations living and interacting in the same area
Biotic factors
Predation
Food availability
Intraspecific competition
Interspecific competition
Cooperation between organisms
Parasitism
Disease
intraspecific competition
arising when individuals of the same species compete for resources
Interspecific competition
arising when individuals of different species compete for resources
Availability of food effects?
- organisms have a higher chance of surviving and reproducing
- their populations can increase
New predators effects?
balanced ecosystems - predators catch enough prey to survive, but not so many they wipe out the prey population.
New predators introduced to the ecosystem, ecosystem becomes unbalanced
New pathogens effects
New pathogens entering = populations will have no immunity or resistance to it and the population may decline.
Competition effects
Better adapted species will outcompete ither species until there are too few members of the lesser adapted species to breed successfully
Abiotic factors
Light intensity and wavelength
Temperature
Turbidity, or cloudiness, of water
Humidity
Soil or water pH
Soil or water salinity
Soil composition
Oxygen or Carbon dioxide concentration
Light intensity
Light needed by plants for photosynthesis - more light = increased plant growth rate
Temperature
affects rate of photosynthesis in plants
Wind intensity and direction
- wind speed affects transpiration rate in plants
Transpiration affects the rate of photosynthesis
soil ph/ mineral conc/ water levels
certain animals adapted to certain conditions
Niche
Role of a species within its habitat
Two species in one niche? =
competition
Hoe does the niche filled by a species determine its abundance within a habitat
abundance = number of individuals of a particular species living in a habitat
2 species in one niche = competition = populations are smaller and therefore abundance will be lower
How do niches influence distribution
Species can only survive in habitats where they are well adapted -
not being well adapted = they move to a more suitable habitat and distribution changes
Fist stage of succession
Primary succession - seeds and spores that are carried by wind land on rock and begin to grow
These are known as pioneer species - i.e. mosses and lichens.
Lichens slowly break apart the top surface of bare rock - forming a basic soil
Pioneer species germinate easily and withstand harsh conditions
Second stage of succession
pioneer species die and decompose - dead organic matter forms thin soil - humus.
Plants are adapted to survive in the shallow nutrient poor soils.
Roots of these small plants stabilise the soil. These small plants die and decompose and the soil becomes deeper and more nutrient rich
Larger plants, shrubs, and small trees begin to grow - these require more water which can be stored in deeper soils
Third stage of succession
soil becomes sufficiently deep, supports large trees.
Final species colonise the newly formed land and outcompete previous species (including the pioneer species)
Stable, final community form which is known as the climax community
How can newly exposed land form?
Landslide exposing bare rock,
or a glacier retreating
Secondary succession
Previous communities destroyed (i.e. by a wildfire or deforestation.)
succession occurs against but the difference is that the soil is already present so the process begins at a later stage.
Pagioclimax
Human activities preventing/ interrupting the process of succession - preventing a climax community from developing
some causes of pagioclimax
Regular mowing and grazing activity
Producers
plants that convert light energy into chemical energy
primary productivity
rate at which producers convert light energy into chemical energy
Gross primary productivity (GPP)
rate at which chemical energy is converted into carbohydrates during photosynthesis
Net Primary Productivity (NPP)
NPP = GPP - R (respiration losses which isn’t stored as new plant biomass and won’t be passed onto herbivores aka primary consumers.)
NPP Definition
rate at which energy is stored in plant biomass
what does NPP show?
The energy available to organisms at higher trophic levels in the ecosystems - primary consumers and decomposers
NPP units - energy and area
Using area: J m–2 yr-1 (joules per square metre per year)
NPP units - volume and time
Using volume: J m–3 yr-1 (joules per cubic metre per year)
used when calculating NPP in aquatic habitats
Primary Consumers
Animals that eat plant material- herbivores/ omnivores
What is chemical energy used for
Chemical energy is used to fuel respiration but also builds up biomass in the tissues when ingested
What happens when an organism dies?
Chemical energy stored in its tissues passes to decomposers
Trophic level 1
Producer
Trophic level 2
Primary Consumer
Trophic Level 3
Secondary Consumer
Trophic level 4
Tertiary Consumer
Trophic level 5
Quaternary Consumer
Arrows in a food chain represent what?
Transfer of energy between trophic levels
Why are food chains never 100% efficient?
Energy is lost to the environment at every trophic level
How is light not available to producers for building biomass
- light passes through the leaves or is reflected away
- light hits the non-photosynthetic part of the plant
- only certain wavelengths are absorbed in photosynthesis and light is a mixture of wavelengths
-Energy released during photosynthesis, some is lost to the environment in the form of heat
Why is 90% of energy lost to the environment
- Not every part of the food organism is eaten
- consumers are unable to digest all the food they ingest like cellulose or fur so it gets egested as poop
- respiration causes energy loss - heat is lost to the environment
- excretion - urea in urine, sweat etc.
net productivity
rate at which energy is converted into biomass in the body of a consumer
Percentage of energy available to organism at next level vs wasted
10 available/ 90 wasted
Energy efficiency equation
Energy efficiency = (net productivity/ energy received) x 100
- can also be calculated by subtracting energy losses from energy received *
How is biomass calculated
Dry biomass - drying a sample of the organism in an oven at low heat and weighing the sample at regular intervals until the mass becomes constant
The organism must be dead for this process to be carried out
Why is dry biomass used
the amount of water stored in tissues can vary
efficiency of biomass transfer percentage equation
EoB = (biomass transferred/ biomass intake) x100
biomass transferred - biomass passed onto higher trophic level
biomass intake - biomass of the lower trophic level that has been consumed
