4.1 Species And Ecosystems Flashcards
What is a species?
Group or organisms that can interbreed to produce fertile, viable offspring
What is it called when 2 different species produce offspring by cross-breeding?
Hybrids (reproductively sterile)
What is a population?
Group of organisms of the same species living in the same area at the same time
What is a community?
A group of populations living together and interacting with each other within a given area
What is a habitat?
Environment in which a species normally lives
What is an ecosystem?
A community and its abiotic environment
What is ecology?
Study of relationship between living organisms/ and their environment
How do autotrophs (producers) obtain chemical energy? (2)
- Synthesis its own organic molecules from simple inorganic substances
- from sunlight (photosynthesis) or via oxidation of inorganic molecules (chemosynthesis)
How do heterotrophs (consumers) obtain energy? (2)
- from other organisms
- can’t produce their own organic molecules
How do mixotrophs obtain energy?
- using both forms
- eg. Photosynthesising but also feed on detritus
What are the three types of ways that heterotrophs obtain organic molecules?
- Consumers - ingest og from living/recently killed organisms
- Detritivores - ingest og found in non-living remnants of organisms (detritus/humus)
- Saprotrophs - release digestive enzymes and then absorb the external products of digestion (decomposers)
What are some examples of the simple inorganic substances required for synthesis? (5)
Carbon, nitrogen, hydrogen, oxygen and phosphorus (from air, water and soil)
What are the 3 types of consumers?
Herbivores - plant matter
Carnivores - animal matter
Omnivores - both plant and animal matter
How do scavengers feed?
Dead and decaying matter instead of hunting live prey
How do detritivores obtain nutrients? (2 ways)
Detritus - dead, particulate organic matter (decaying organic matter and fecal matter)
Humus - decaying leaf litter with topsoil
How do saprotrophs obtain nutrients?
Enzymatic secretion to facilitate external digestion
How does nutrient cycling work? (4 steps)
- Autotrophs obtain inorganic nutrient from air, water and soil and convert them to organic compounds
- Heterotrophs ingest organic compounds and use them for growth and respiration (releasing inorganic by products)
- Organisms die and saprotrophs decompose the remains and free inorganic material into soil
- Return of inorganic nutrient toi soil ensured continual supply of raw materials for the autotroph
What are the three main components required for sustainability in ecosystem?
Energy availability - light from sun
Nutrient availability - decomposers ensure constant recycling of inorganic nutrients
Recycling of waste - cortina bacteria detoxify harmful waste byproducts
What are mesocosms?
Enclosed environments that allow small part of natural environment to be observed under controlled conditions
(Eg. Terrarium)
What is positive association? (And relationship)
If two species are typically found within the same habitat
- exhibit predator-prey / symbiotic relationship
What is a negative association?
If two species tend to not occur within the same habitat
why may species typically show a negative association if there is competition for the same resources? (2)
- One species may utilise the resources more efficiently (competitive exclusion)
- Both species may alter their use of the environment to avoid direct competition (resource partitioning)
What occurs is the species do not interact? (2 points)
There will be no association between then
Their distribution will be independent of one another
What is a quadrat?
A rectangular frame of known dimensions that can be used to establish population densities
How do you use a quadrat? (3)
- Quadrats are placed inside a defined area in either a random arrangement or according to a design
- Number of individual of a given species is either counted or estimated via percentage coverage
- Sampling process is repeated many times in order to gain representative data set
How to do a chi-squared test?
- Identify hypothesis (null v alternative)
- Construct a table of frequencies
- Apply the chi-squared formula
- Determine the degree of freedom
- N’identifiât the p value
Do a chi-squared test
