BIO173 Exam 2

Ecological diversity

The variety of ecosystems, habitats, and ecological processes in an area.

Community composition

The types of species present in a community and their relative abundances.

Species interactions

Relationships between species that affect survival, growth, or reproduction.

Competition

When organisms use the same limited resources.

Interspecific Competition

Competition between different species.

Intraspecific Competition

Competition between the same species.

Interference Competition

Preventing another organism from accessing resources.

Exploitative Competition

Indirect competition by using up shared resources first.

Mutualism

An interaction where both species benefit.

Commensalism

An interaction where one species benefits and the other is unaffected.

Amensalism

An interaction where one species is harmed and the other is unaffected.

Predation

One organism kills and eats another organism.

Parasitism

One organism benefits while harming another without immediately killing it.

Independent variable

The factor that is intentionally manipulated in an experiment.

Dependent variable

The factor that is measured in response to change in the independent variable.

Positive control

A group expected to produce a known result, showing the experiment works correctly.

Negative control

A group expected to show no effect, used for comparison.

Hypothesis testing

Using data to determine whether evidence supports a prediction.

Null hypothesis

The assumption that there is no effect, no difference, or no relationship.

de Wit Replacement Series

An experiment comparing how species grow alone versus together at different ratios.

Monoculture

Growing only one species in an area.

Mixed Culture

Growing two or more species in an area.

Destructive Sampling

Collecting data by removing or destroying organisms.

Biodiversity

The variety of life in a given area.

Habitat Diversity

The number of different habitat types in an area.

Species Diversity

The variety of species in an area.

Richness

The number of different species.

Evenness

How evenly individuals are distributed among species.

Genetic Diversity

Variation in genes within a species.

Biogeography

The study of where organisms live and why they are found there.

Assemblage

A group of species living in the same area.

Evolution (Descent with Modification)

The process by which species change over time through inherited traits.

Natural selection

The process where individuals with helpful traits survive and reproduce more successfully.

Adaptation

A trait that improves survival or reproduction.

Adaptive Evolution

Changes in a population that make it better suited to its environment.

Speciation

The formation of a new species by an ancestral population splitting into two or more genetically distinct species

Micro Evolution

Small changes in gene frequencies within a population.

Macro Evolution

Large-scale evolutionary changes over long periods, such as the formation of new species.

Unity & Diversity of Life

The idea that all life shares common ancestry but has many different forms.

Phylogeny - Evolutionary Tree

The evolutionary history and relationships among species.

Shared Characteristics

Traits organisms have in common due to shared ancestry.

Classification

Grouping organisms based on shared features.

Taxonomy

The science of naming and classifying organisms.

Dichotomous Key

A tool that identifies organisms through a series of paired choices.

Artificial Selection

Humans choosing which organisms reproduce based on desired traits.

Law of Succession

The idea that extinct species are similar to living species found in the same area.

Homologous Structures

Body parts in different species that came from a common ancestor, even if they have different functions.

Sexual Dimorphism

Physical differences between males and females of the same species.

Transitional Forms

Fossils or organisms that show traits between older and newer groups.

Molecular Homology

Similarities in DNA or proteins among species due to common ancestry.

Bipedalism

Walking on two legs.

Convergent Evolution

When unrelated species evolve similar traits because they live in similar environments.

Vestigial Structures

Body parts that no longer have an important function but were useful in ancestors.

Mean (average)

The averages of a set of values.

Variance

A measure of how spread out data are from the mean.

Standard Deviation

A measure of the average distance of data points from the mean.

Normal Curve

A bell-shaped graph showing how data are distributed around the mean.

T-score

A value used in statistics to compare differences between groups.

p-value

The probability that the observed results happened by chance if the null hypothesis is true.