Topic 4.1: Species, communities, and ecosystems Flashcards
Definition of ecology
The study of the relationships between living organisms and their environment.
Definition of species
A group of organisms that can potentially interbreed to produce fertile offspring.
Definition of population
A group of organisms of the same species, living in the same area at the same time.
Definition of community
A group of different populations living together and interacting with each other in a given area.
Definition of habitat
The environment in which a species normally lives
Definition of ecosystem
The interaction of a community and its abiotic environment
What might happen if two populations of a species never interbreed?
Develop differences in their characters
Can members of the same species be reproductively isolated in separate populations?
Yes. This does not mean that they are different species if interbreeding is functionally possible.
Main features of the members of a same species (2)
a) Similar physical characteristics
b) Can interbreed and produce fertile offspring
Exception to the definition of species
Some organisms reproduce asexually
Main modes of nutrition (2)
a) Autotrophs
b) Heterotrophs
Autotrophs definition
Synthesize their own organic molecules from inorganic molecules (through photosynthesis)
Heterotrophs definition
Obtain organic molecules from other organisms (via different mechanisms and sources)
Classification of heterotrophs (3)
a) Consumers
b) Saprotrophs
c) Detritivores
Consumers definition
Feed on living organisms by ingestion
Saprotrophs definition
Obtain organic nutrients from dead organims by external digestion
a) Secreting enzymes
b) Absorbing matter
Detritivores definition
Obtain nutrients from detritus (decomposing and fecal matter) by internal digestion
Mixotrophs definition
Use both modes of nutrition (e.g., Euglena gracilis)
Questions to classify species based on their modes of nutrition (2)
a) Does it possess cell walls?
b) Does it feed on dead organic matter?
What are ecosystems able to do?
Be sustainable over long periods of time
Requirements for sustainability in an ecosystem (3)
a) Energy availability (e.g., sunlight)
b) Nutrient availability (e.g., decomposers)
c) Waste recycling (e.g., detoxifying bacteria)
Mesocosms definition
Small, enclosed environments under controlled conditions
Mesocosms function (2)
a) Test what types of ecosystems are sustainable
b) Find out the effects of varying the conditions of an ecosystem
Nutrients definition
Materials required by organisms for survival (e.g., N / P / Ca)
What is needed for an ecosystem to provide a limited amount of nutrients?
They must be constantly recycled
Nutrient Cycling
a) Autotrophs convert inorganic nutrients into organic matter
b) Heterotrophs ingest organic molecules and may release inorganic byproducts.
c) Saprotrophs break down the nutrients in dead organisms and return them to the soil.
Positive species association
If two or more species are always found in the same habitat
a) Predator / prey relationship
b) Symbiotic interaction
Negative species association
If species do not share the same habitat
a) Competition
Quadrat sampling function
Determine the presence of a species in a given area
Quadrat sampling method
a) Rectangular frame placed in an area (repeat sampling)
b) Species numbers within the frame are counted.
Function of Chi-Squared Test in Ecology
To determine if there is a statistically significant association between the distribution of two species.
Quadrat sampling function
Determine the presence of a species in a given area
Subclassification of consumers (4)
a) Herbivores (Plant matter)
b) Carnivores (Animal matter)
c) Omnivores (Both matters)
d) Scavengers (Decaying carcasses)
