Slide Set 1 Ecology: Patterns and Processes

What is the projected fate of African elephants if current trends continue?

African elephants are projected to be extinct in their natural habitat by 2040-2050 given current rates of decline.

What are the main causes of African elephant population decline?

Poaching, habitat destruction/loss, disease, loss of genetic diversity, and climate change.

What information is needed to prevent African elephant extinction?

How many elephants remain, where they are found, how populations grow or decline, and the causes of those changes.

What questions does ecology aim to answer?

Where organisms are found, how many there are, and why they are distributed that way.

What is ecology?

The study of the distribution and abundance of organisms and the factors and interactions that determine them.

Who coined the term "ecology" and when?

Ernst Haeckel in 1866, derived from the Greek word Oikos (home)

What disciplines influenced the development of modern ecology?

Natural history, human demography, biometry, and applied agriculture and medicine.

How did hunters and gatherers contribute to ecological knowledge?

Through observations of animals, plants, and environmental patterns necessary for survival.

What was Aristotle's contribution to ecology?

Wrote Historia Animalium (~350 BC), an early systematic study of animals.

What is Providential Ecology and who contributed to it?

The idea that nature exists for human benefit; associated with Herodotus and Plato.

Who contributed early ideas about population growth?

Graunt (1662) and Leeuwenhoek (1687).

What is Farr's Rule?

A relationship between population density and mortality rate.

Who contributed to ideas of population regulation?

Buffon (1756), Malthus (1798), Quetelet (1835), and Verhulst (1838).

Who were key founders of experimental ecology?

A.G. Tansley (1904), F.E. Clements (1905), and Charles Elton (1927).

Who studied community regulation and succession?

Edward Forbes (1887) and Henry Cowles (1899).

Who developed early mathematical models of disease spread?

Ronald Ross (1908).

Who helped bring ecology into public awareness in 1962?

Rachel Carson.

How has ecology changed in the last 50 years?

It has become more rigorous, using conceptual theory, mathematics, experimentation, and guiding environmental science.

What is meant by interaction in ecology?

Organisms are affected by the environment and also modify it.

What are abiotic components?

Non-living physical and chemical factors like temperature, light, nutrients, and water.

What are biotic components?

Living factors such as other organisms, competition, and predation.

What are the levels of biological organization from smallest to largest?

Molecule → Organelle → Cell → Tissue → Organ → Organism → Population → Community → Ecosystem → Biosphere

What scales does ecology typically operate at?

Higher levels of biological organization across large spatial and temporal scales.

What is an organism?

A single individual of a single species.

What is a population?

Individuals of the same species living in the same geographic area.

What is a community?

Two or more populations living in the same geographic area.

What is an ecosystem?

A community and its interactions with the physical and chemical environment.

What is the biosphere?

Parts of the atmosphere, hydrosphere, and lithosphere occupied by life.

What processes occur at higher ecological levels?

Energy flow, nutrient cycling, species interactions, and population dynamics.

How do ecological explanations differ from physiological ones?

Ecology operates over larger spatial scales and longer time scales.

What are the four sources of ecological evidence?

Observation/monitoring, manipulative field experiments, lab experiments, and mathematical models.

What is the main goal of ecology?

To observe patterns, describe processes, and predict, manage, and control ecological systems.

Why are statistics important in ecology?

They provide confidence in conclusions and allow population-level inference from samples.

What is random sampling?

Collecting representative samples to reduce bias and sampling error.

What are population parameters?

Numerical features of a population estimated using statistics.

What is a null hypothesis?

The assumption that there is no association between measured variables.

What is a P-value?

The probability of obtaining results as extreme as observed if the null hypothesis is true.

When are results statistically significant?

When P < 0.05.

What does a frequency distribution show?

How often values occur across a range.

What does the y-axis represent in a frequency distribution?

Frequency (how often values occur).

What are characteristics of a normal distribution?

Symmetrical, single peak (mean), 50% on each side.

What controls the spread of a normal distribution?

Variability, measured by standard deviation.

What is a Z-test statistic?

The number of standard deviations a value is above or below the mean.

What is standard error?

Standard deviation divided by the square root of sample size.

What was the standard error in the chimpanzee termite example?

2 (10 ÷ √25)

What was the Z-score in the chimpanzee example?

-2

What decision was made about the null hypothesis?

Reject the null hypothesis.

What conclusion was drawn from the Z-test?

The troop captured fewer termites than other troops.

What is the core takeaway of ecology as a science?

Ecology relies on scientific evidence, statistics, and multiple methods to understand patterns and processes across scales.