Understanding Evolutionary Fitness

• Grasp the concept of evolutionary fitness, which is focused on reproduction and passing on genes to the next generation, rather than physical fitness or strength.
• Familiarise with natural selection as a process where organisms with traits better suited to their environment have a higher chance of surviving and reproducing, hence passing on their beneficial traits to the next generation.
• Understand the importance of both survival and reproduction in evolutionary fitness: surviving without reproducing doesn't contribute to the gene pool of the next generation.

Fitness and the Environment

• Acknowledge that an organism's fitness depends on its environment, as different traits are advantageous in different settings.
• Recognise that changes in the environment can lead to changes in which traits are advantageous, therefore affecting fitness.
• Understand that fitness is a relative measure, dependent on the ability to survive and reproduce compared to other organisms in the population.

Genotype and Phenotype

• Understand that genotype refers to the genetic makeup of an organism, while the phenotype includes all observable traits which are influenced by both genes and environment.
• Realise that natural selection acts on phenotypes because they determine how well an organism can survive and reproduce in its environment.
• Accept that there is often a range of phenotypes within a population due to genetic variation: some of these may be more fit for survival and reproduction.

Adaptation and Fitness

• Understand that adaptations are traits that increase the fitness of an organism in its environment, resulting from the process of natural selection.
• Acknowledge that these beneficial traits, or adaptations, become more common in the population over time due to their contribution to fitness.
• Recognise that over many generations, this can lead to the evolution of new species, a process known as speciation.

Measuring Fitness

• Identify reproductive success as the most accurate measure of fitness from an evolutionary perspective.
• Understand that an organism's overall fitness includes both its personal reproductive success and the success of its relatives (known as inclusive fitness).
• Appreciate that while difficult to measure directly, fitness can be estimated using proxies, like the number of offspring an organism has that survive to reproduce themselves.