Adaptation and Variation

Organisms face environmental challenges that limit their ability to survive. These include severe weather, lack of food and competition (for food, space and mates). Diversity within a species and its interactions with their environment are the reasons why one population changes over time while another may become extinct. Adaptation: a structure, behaviour or process that helps an organism survive and reproduce in their environment.

Examples of Adaptations hibernation sharp talons and excellent hearing in an owl camouflage

Mimicry: a structural adaptation where a harmless species resembles a harmful species Example: Viceroy and Monarch butterflies

Mimic Octopus

Development of Adaptations Adaptations result from gradual and accumulative changes that help an organism survive and reproduce in its environment. These changes are due to random heritable mutations in DNA. Variation: differences between individuals (structural, functional or physiological) Not all variations develop into adaptations. If a variation increases an individual’s ability to survive in its environment, those individuals with the variation will be more likely to reproduce.

This results in the variation becoming more frequent and will eventually be considered a trait of the population. (i.e. an adaptation) Mutations in gamete DNA is the origin of genetic variation in a population. If a mutation increases an individual’s chance of survival in its environment, it is called a selective advantage. Over time the gene that provided the selective advantage will become more prevalent in the population. (i.e. antibiotic resistant bacteria)