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• https://www.youtube.com/watch?v=PmDTtkZlMwM

• Mimicry: a structural adaptation where a harmless species resembles a harmful species

• Example: Viceroy and Monarch butterflies

• Mimic Octopushttps://www.youtube.com/watch?v=H8oQBYw6xxc

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)