Biology Module 3

Selection Pressures

The biotic and abiotic factors of an ecosystem that affect an organism’s behaviour, survival, and reproduction.

Population

All of the organisms from the same species living in a particular area.

Community

A group of populations in a particular area.

Ecosystem

A community of living organisms that interact with each other and their surrounding environment.

Effects of Selection Pressures

Organisms best suited to selection pressures tend to be more abundant and reproduce more.

Favourable Traits

Characteristics that are advantageous for survival and reproduction in a given environment.

Invasive Species

An organism that is not native to a specific location and can act as a selection pressure on native organisms.

Predation

One animal killing another for food.

Parasitism

One organism benefits at the expense of another, usually without killing them.

Commensalism

One organism benefits while the other is neither harmed nor benefited.

Mutualism

Both organisms benefit from the relationship.

Competition

Organisms competing over the same resource, space, or mate, resulting in harm to both.

Adaptations

Specific features of an organism that enable survival and reproduction in a specific environment.

Structural Adaptations

Physical features of an organism that enhance its suitability to the environment.

Physiological Adaptations

Internal bodily functions that help an organism survive in its environment.

Behavioural Adaptations

Actions taken by an organism to improve its chances of survival.

Biological Diversity

The variety of life forms, including genetic, species, and ecosystem diversity.

Genetic Diversity

Variation in genetic makeup within a population, important for adaptation.

Convergent Evolution

Distantly related species evolve similar traits due to similar environmental pressures.

Divergent Evolution

Ancestral species radiate into descendant species with both similar and different traits.

Gradualism

Evolution occurs slowly over time through small changes in characteristics.

Punctuated Equilibrium

Evolution occurs in bursts of rapid change followed by long periods of stability.

Theory of Evolution by Natural Selection

Living organisms arise from common ancestors and change over time.

Speciation

The formation of a new and distinct species during evolution.

Macroevolution

Large-scale evolutionary changes that result in new species over millions of years.

Microevolution

Small-scale changes within a population that do not generally produce new species.

Mutation

A change in the sequence of an organism's DNA.

Migration

The movement of genetic diversity within a species.

Genetic Drift

Changes in gene frequency in a population due to random chance.

Fossils

Remains, impressions, or traces of life forms preserved in material such as ice or sediment.

Relative Dating

Arranging fossils in chronological order without providing a numerical age.

Absolute Dating

Provides a precise estimate of a fossil’s age using quantitative methods.

Radiometric Dating

Determining the age of rocks or fossils from the decay of radioisotopes.