module 6.3.1: ecosystems Flashcards
what is a habitat
a place where an organism lives
what is a population
all the organisms of one species who live in the same place at the same time and can breed together
what is a community
all the populations of different species who live in the same place at the same time and who can interact with each other
what is an ecosystem
a community of animals, plants and bacteria interrelated with the physical and chemical environment. ecosystems can be referred to on a large scale, such as an African grassland, a medium scale, such as a playing field, or a small scale, such as a rock pool or a large tree
what is biotic factors
environmental factors associated with living organisms in an ecosystem that affect each, such as predation or disease. They impact each species and individual because all species in an ecosystem are interrelated
what is a producer
plants and photosynthetic bacteria that supply chemical energy to all other organisms, whilst the numbers of primary (feed on producers), secondary (feed on primary), and tertiary (feed on secondary) consumers will affect the populations of each other and the producers
what is a decomposer
bacteria, fungi and other organisms that feed on waste material or dead organisms
what is a abiotic factor
the nonliving characteristics of an ecosystem that affect other living organisms, such as the pH, relative humidity, temperature, and concentration of pollutants. at extreme values of an abiotic factor, a species may perform better or worse, or even die. examples include salinity, light, temperature, water and oxygen availability, and edaphic factors
what cause dynamic changes
due to change in and interaction between the biotic and abiotic factors
what are cyclic changes
repeat themselves in a rhythm such as the movement of tides and day length
what are directional changes
go in one direction, i.e: deposition of silt into an estuary, or erosion of a coastline
what are unpredictable/erractic changes
have no rhythm or constant direction, i.e: a sudden natural disaster
why is the transfer of biomass between trophic levels is inefficient and the cumulative biomass is reduced at each stage
because living organisms use some of the energy for physiological processes so it is lost as heat. The gross production of organic matter by autotrophic producers is only 1-3% of the solar energy because most is reflected, some is used to sustain the photosynthetic reactions, and other factors such as water availability limit the rate of photosynthesis
what biomass is lost in the transfer in between primary consumers from producers
lost in dead plant matter and parts of the plant not eaten
how much of the net production is passed to the next trophic level
only 5-10% of the net production is passed to the next trophic level
