Biology HL Vocabulary Flashcards
(21 cards)
Standard Deviation
Used to summarize the spread of values around the mean.
Useful for comparing the means and spread of data between two or more samples.
What does normal distribution mean?
68% of the data is within -1.0 and +1.0 standard deviations. More than 96% of the area is between -2.0 and +2.0 SD.
What do tall and short SD graphs represent?
Tall: low variability/small SD
Short: more variability/big SD
Statistical Significance
The t-test is used to determine if there is a significant difference between two data sets.
To apply the test you must have:
1. Normally distrubited population (68% and 95%)
2. Continuous data (not different things ie male vs female)
3. Sample size >30.
What are other names for a t-table?
Alpha-values, confidence levels, P values, level of significance.
When do you use one tailed vs two tailed t-test?
Two tailed: going to be a difference (unknown how).
One tailed: going to be a specific difference.
Error Bars
Show the range of data or the standard deviation +/-
Uncertainties
Shows the precision of an instrument or accuracy of data collection.
ie some themometers have an uncertainty of +/- 0.1 degree C.
Causation vs. Correlation
Causation: a change in x causes a change in y
Correlation: when two sets of data are strongly linked together we say they have a high correlation
GREATER SD MEANS MORE CORRELATION
What’s an example of Causation vs. Correlation?
Polio virus that spreads in water… strong correlation between ice cream and polio, but the causation is not ice cream.
Ecosystem
All communities, plus abiotic and geographical aspects.
- Biotic
- Abiotic
- A geographical area
Community
A group of populations of different species (JUST BIOTIC).
Population
a localized group of the same species that can interbreed producing fertile offspring
Species
A group of populations who can reproduce within their own group
Examples of Ecosystem, community, population, and species in relation to humans.
Species: humans
Population: a location (the people in Niwot)
Ecosystem: in Niwot, humans, animals, plants, precipitation, and rocks within area.
Community: all biotic aspects (not rocks).
Autotrophs
PRODUCERS, and they convert sun’s energy into chemical energy.
Heterotrophs
CONSUMERS, can use the chemical energy produced by the autotrophs
Detrivores
Consumer that derives its energy and nutrients from nonliving organic material (ie corpses, fallen plant material, wastes of living organisms) ONLY ANIMALS
sea stars, slugs, millipedes
Saprotropha
organism that uses extracellular digestion. Extretes digestive enzymes
How is energy measured?
In kJ m^-2 y^-1 or kJ/m^2/y
energy per square meter per year
Do autotrophs or heterotrophs use more energy?
Heterotrophs, because they move more than autotrophs (plants) do.
