Glossary
Adaptation
A heritable trait that increases an organism's fitness in its environment, arising from natural selection over generations.
Example:
The thick blubber of a polar bear is an adaptation that helps it survive in extremely cold Arctic conditions.
Alleles
Different versions or forms of a gene that occupy the same locus on homologous chromosomes.
Example:
The gene for human blood type has three common alleles: A, B, and O, which combine to determine an individual's blood group.
Differential Reproductive Success
The phenomenon where some individuals in a population produce more offspring than others due to differences in their traits, leading to certain traits becoming more common over time.
Example:
A plant that produces more viable seeds in a dry environment than its peers demonstrates differential reproductive success, ensuring its drought-resistant genes are widely distributed.
Ecological Niches
The specific role and position a species has within its environment, including its interactions with biotic and abiotic factors.
Example:
A woodpecker's ecological niche involves drilling into trees for insects, utilizing a specific food source and habitat.
Evolution
The process by which populations of organisms change over generations, driven by mechanisms like natural selection, genetic drift, gene flow, and mutation.
Example:
The development of antibiotic resistance in bacteria is a rapid example of evolution occurring through natural selection.
Genotype
The specific genetic makeup of an individual, referring to the set of alleles an organism possesses for a particular gene or genes.
Example:
If a pea plant has the genotype 'Tt' for height, it carries one allele for tallness and one for shortness.
Heritable Variation
Differences in traits among individuals within a population that can be passed down from parents to offspring.
Example:
The different fur colors seen in a litter of puppies represent heritable variation, as these traits were inherited from their parents.
Natural Selection
The process by which individuals with traits better suited to their environment are more likely to survive and reproduce, leading to an increase in the frequency of those advantageous traits in the population over generations.
Example:
In a forest with dark tree trunks, natural selection would favor moths with darker wings, making them less visible to predators and more likely to pass on their genes.
Phenotype
The observable physical or biochemical characteristics of an organism, resulting from the interaction of its genotype with the environment.
Example:
A person's blue eyes are a phenotype, which is the visible expression of their specific eye color genes.
Phenotypic Plasticity
The ability of a single genotype to produce different phenotypes in response to varying environmental conditions.
Example:
A chameleon changing its skin color to match its surroundings is a classic example of phenotypic plasticity, adapting its appearance without altering its genes.