Marine Science Practical Skills and Data Analysis

Vocabulary practice flashcards covering marine science practical skills, experimental design, sampling methods, and statistical analysis based on lecture transcripts.

Qualitative observations

Descriptive observations that do not involve numerical values.

Quantitative observations

Numerical values obtained through measurements or counting.

Hypothesis

A possible answer to the question "why" that attempts to explain an observation.

Prediction

A statement of what you think will happen in an experiment, linked to the hypothesis.

Independent variable

The variable that is being changed or manipulated in an experiment.

Dependent variable

The variable that is being measured in an experiment.

Control variables

Variables not being tested that must be kept the same or constant to ensure a fair test.

Confounding variables

Variables that cannot be controlled but must be recorded because they can affect the dependent variable.

Control group

The group treated the same way as the experimental group but without exposure to the independent variable.

Safety

The consideration of hazards and risks during an experiment.

Ethics

How you treat living organisms to avoid causing them harm during an investigation.

Water bath

A large container with hot or cold water used to control temperature.

Thermostatically controlled water bath

A water bath with heating units that maintain temperature within programmed limits.

Buffer

A solution used to control pH by remaining at the same level even if acid or base is added.

Hydrogen carbonate solution

A solution used to increase the level of carbon dioxide ($CO_2$) in an experiment.

Light intensity control

Maintaining an equal distance from a light source to keep the variable constant.

Graduated cylinder

Equipment used to measure the volume of a liquid.

Syringe or pipette

Equipment used for measuring liquid volumes less than $10,cm^3$.

Weighting scale or balance

Equipment used to measure mass.

Stopwatch

Equipment used to measure time.

pH probe

An instrument used to take precise pH measurements.

Minimum independent variable values

You should aim to have at least $5$ values for the independent variable to see trends.

Replicates (trials)

Taking at least $3$ readings at each value of the independent variable.

Anomalous results

Individual results that do not fit the pattern of the rest of the data and may cause errors.

Mean calculation rule

Anomalous results should not be used when calculating average values.

Data Table Precision

Recording results using the same number of decimal places for every result.

Scientific Drawing: Lines

Should be a single unbroken line and avoid shading.

Scientific Drawing: Size

Should be large enough to fill at least two-thirds of the available space.

Label lines

Ruler-drawn lines used to identify structures on diagrams without an arrowhead.

X-axis

The horizontal axis where the independent variable is plotted.

Y-axis

The vertical axis where the dependent variable is plotted.

Line graph

A graph used to show the relationship between two continuous variables.

Plotted points

Marked on a graph using an "X" or a small circle with a dot in the middle.

Dual Y-axes

Used when two different dependent variables must be plotted against the same independent variable.

DRY MIX

Acronym: Dependent Responding Y-axis; Manipulated Independent X-axis.

Continuous variables

Variables like temperature, time, depth, or salinity that show a continuous range.

Histogram

A graph used for frequency data where bars are connected with no space between them.

Bar chart

A graph for discontinuous data showing relationships with gaps between bars.

Systematic errors

Errors from incorrect equipment readings that affect all results equally and reduce accuracy.

Random errors

Errors caused by failing to control variables, affecting results in different ways.

Data Confidence

Determined by less variation in repeated results, leading to accurate measurements and valid conclusions.

Significant figures (s.f.) rule

Aim for the same amount of s.f. as the least precise part of the calculation.

Refute

The act of scientific data showing that a given hypothesis is not supported.

Mark-release-recapture

A technique used to estimate the population size of mobile organisms.

Lincoln Index formula

$$N = \frac{n_1 \times n_2}{m}$$

$$n_1$$

The number of individuals captured in the first sample of a mark-release-recapture study.

$$n_2$$

The number of both marked and unmarked individuals captured in the second sample.

$$m$$

The number of marked individuals recaptured in the second sample.

Random sampling

A technique used for small, sessile organisms involving quadrats at random coordinates.

Frame quadrat

Equipment used for random sampling, most commonly $1\,m^2$ in size.

Systematic sampling

Sampling along an environmental gradient using a transect.

Line transect

A sampling method where species touching a line are recorded, either continuously or at intervals.

Belt transect

A method where a frame quadrat is placed at regular intervals on one side of a line.

Simpson’s index of diversity (D)

A value between $0$ and $1$ used to calculate species richness and evenness.

D = 0

Represents no diversity where all individuals in an area are the same species.

D = 1

Represents maximum diversity in a habitat.

Low species index of diversity

Indicates few successful species, an extreme environment, and simple food webs.

High species index of diversity

Indicates a stable ecosystem with many niches and complex food webs.

Spearman’s Rank Correlation ($r_s$)

A statistical test used to find out if there is a correlation between two sets of variables.

Perfect negative correlation

Indicated by a Spearman’s Rank Correlation coefficient ($r_s$) of $-1$.

Perfect positive correlation

Indicated by a Spearman’s Rank Correlation coefficient ($r_s$) of $+1$.

No correlation

Indicated by a Spearman’s Rank Correlation coefficient ($r_s$) of $0$.

Null hypothesis ($H_0$)

The starting assumption that there is no correlation between two variables.

Spearman’s Rank steps

Rank data, assess difference (D), find $D^2$, find $\sum D^2$, and substitute into the formula.

Critical value

A value used to compare against the calculated $r_s$ to determine significance.

Rejecting the Null Hypothesis

Occurs when the calculated correlation coefficient is greater than the critical value.

Causal relationship

A link where one variable directly causes a change in another; correlation does not imply this.

Abiotic factors

Non-living factors, such as dissolved nutrients, that can cause relationships in data.

Biotic factors

Living factors, such as predators, that can cause relationships in data.

Thermometer

Equipment used to measure temperature to ensure it remains constant.

Universal indicator

A chemical used to measure the pH of a solution.

Anomalous result identification

Results that do not follow the trend of replicates at the same independent variable value.

Data Table Heading

Columns must include descriptions of variables and their specific units.

Graph Scale

Must be suitable and use at least $75\%$ of the space provided.

Best fit line

A line that represents the trend of data; it can be a straight line or a curve.

Discontinuous data example

The average number of spiny lobsters at four different specific beaches.

Accuracy improvement

Achieved by having more repeats and using more precise equipment.

Mean (average) location

Should be placed in its own column in the data table.

Drawing proportions

Structures in a drawing should be well proportioned and to scale.

Mobile organisms

Organisms that move, requiring mark-release-recapture for population estimation.

Sessile organisms

Organisms that are small and do not move, allowing for random sampling with quadrats.

Marking limitations

Paint wearing off, tags being lost, or marks increasing the chance of predation.

Population changes in sampling

Mark-release-recapture does not account for organisms moving in/out or births/deaths.

Species richness

Number of different species present in a particular habitat.

Species evenness

How close in numbers each species in an environment is.

Summation symbol (capital sigma)

The symbol $\sum$ used to indicate adding a series of values together.

Extreme environment diversity

Usually results in a low species index of diversity because few species are well adapted.

Stable ecosystem diversity

Usually results in a high species index of diversity with more available niches.

Rank 1 in Spearman's Rank

The rank given to the highest numerical value in a variable set.

$D$ in Spearman's Rank

The difference between the ranks of two variables for a single sample.

Positive correlation trend

As the independent variable increases, the dependent variable also increases.

Negative correlation trend

As one variable increases, the other variable decreases.

Field experiment limitation

Confounding variables like tides, ocean currents, and weather cannot be controlled.

Hydrogen carbonate solution purpose

Used in aquatic plant experiments to release carbon dioxide into the solution.

Graph Labeling Rule

Both axes must be fully labeled with both description and units.

Measuring $20,cm^3$

Use a $100,cm^3$ cylinder, not a $200,cm^3$ cylinder for better accuracy.

Ethics in collection

Avoiding harm when collecting water samples or organisms from a beach.

Drawing detail expectation

Candidates are not expected to recreate all minor details in a sketch.

Precision example

If one value is $43.345$ and another is $29$, they should be recorded as $43.3$ and $29.0$.

Lincoln Index sample timing

The second sample is taken after a period of time to allow marked individuals to redistribute.