Ecosystems and Succession Flashcards
What is called the biosphere?
- the part of the Earth and its atmosphere that is inhabited by living organisms is called the biosphere
- (it is a global ecosystem made up of living organisms and the non living factors that provide them with energy and nutrients)
What are the two factors that make up an ecosystem? What do they both refer to?
- the two factors that make up an ecosystem are biotic and abiotic factors
- the abiotic factors = (non-living) physical and chemical factors like the climate and soil type
- the biotic factors = (living) determined by organisms, such as predation and competition
What is the definition of an ecosystem? What do ecosystems include?
- a functional unit that tends to be fairly-self sustaining
- a community of organisms interacting with each other and with the physical environment
- ecosystems include both biotic (living) and abiotic (non-living)
What is the definition of a habitat?
- a habitat is the place or location where an organism or a community of organisms live
What is a population? What makes up a community?
- a population is a group of interbreeding individuals of the same species found in an area
- the various populations sharing a habitat or an ecosystem make up a community
What is the definition of a niche?
- the niche of an organism is the functional role that it plays within an ecosystem
What does anthropogenic factors refer to? Are they abiotic or biotic factors?
- anthropogenic factors are those arising from human activity
- they can be either abiotic or biotic
What does interspecific refer to?
- interspecific refers to interactions or relationships between different species
- “across species variation”
What does intraspecific refer to?
- intraspecific refers to the interactions between the same species
- “within species variation”
What does distribution and dispersion refer to?
- within a range of species, distribution refers to the general structure of the species population
- while dispersion refers to the variation in its population density
What does (species) abundance refer to?
- species abundance refers to the sum total of individuals from a given species within a given area/ ecosystem/ habitat
What controls the abundance and distribution of organisms?
- the abundance and distribution of organisms in a habitat is controlled by abiotic and biotic factors
What are some examples of abiotic factors?
- solar energy input (is affected by latitude, season, cloud cover and changes in Earth’s orbit)
- climate (rainfall, wind exposure, temp)
- topography (includes altitude, slope, aspect/ which direction the land faces, drainage)
- oxygen concentration (important in aquatic systems)
- edaphic (factors are connected with soil/ soil pH)
- pollution
- catastrophes (volcanic eruptions)
What are some examples of biotic factors?
- competition
- predation, disease
- grazing (method of feeding, herbivores consume plants)
- parasitism (symbiotic relationship, parasite feeds off the host)
- mutualism (in which both partners benefit)
What does symbiosis refer to?
- a symbiosis is an evolved interaction or close living relationship between organisms from different species
- usually with benefits to one or both of the individuals involved
What are some examples of symbiotic relationships?
- mutualism (where both individuals benefit)
- parasitism (where the parasite gains benefits that come at the expense of the host member)
- competition
What are some examples of relationships between two organisms where one organism benefits at the other’s expense?
- grazing
- predation
- disease
- parasitism
What factors are usually density dependent? What does this mean? What is the result of a larger population density?
- biotic factors are usually density dependent
- this means the effects are related to the size of the population relative to the area available
- the large the population density, the greater the competition for food, space and so on
Can species share the same habitat if they have the same niche?
- species can only share the same habitat if they occupy a different niche (otherwise the better adapted will outcompete the other)
What is meant by the term succession?
- Idea of a series of changes (that occur to the composition of species in the community) of organisms (present in an area) over a period of time
- (basically a community changes over time)
What does pioneer species refer to? What are some examples of pioneer species? Why these species?
- pioneer species refers to the first organisms to colonise bare rock which are lichens and algae
- these species are the only ones that can cope with the extremes of temperature, and the lack of soil, water and nutrients
What do pioneer species do to rock surfaces? What does this allow? How do then other species grow? What starts growing?
- pioneers start to break up rock surface, allowing some organic material to accumulate with this broken up rock as the beginnings of soil
- they change the conditions in the habitat just enough to make them suitable for other species
- wind-blown moss spores start growing
How does primary succession start? How does secondary succession occur? Without interference, what would secondary succession lead to?
- primary succession starts in newly formed habitats where there has never been a community before
- secondary succession occurs when an existing ecosystem or community has been destroyed, cleared or disturbed
- without (human) interference, secondary succession would lead to the re-establishment of a climax community
What is meant by the term deflected succession?
- deflected succession is when a community remains stable only because human activity prevents succession from running its course
Why do some ecosystems need to be actively managed (to deflect succession)?
- some ecosystems need to be actively managed to prevent succession as it would result in a loss or change in biodiversity in certain habitats
What are some methods that can be used to deflect succession?
- grazing, mowing or burning may be used to deflect succession
What is the definition of colonisation?
- colonisation is a biological process by which a species spreads to new areas
What does climax community refer to?
- climax community refers to a stable ecosystem in its final stage of ecological succession
- in a climax community, the plants and animals are in balance with each other and their environment
What does geographical isolation refer to? What does this prevent?
- geographical isolation refers to the separation of populations due to geographical barriers
- this prevents them from interbreeding
How can water availability be investigated on an area of land?
- using a moisture probe and test the soil around the plants
- use a rain gauge and collect water over a period of time
What are microsatellites?
- microsatellites are small pieces of DNA that repeat
