change in the characteristics of a species over many generations
Evolution
a characteristic of an organism that improves its chances of surviving and/or reproducing
Adaptation
features or characteristics that are passed down through genes
Trait
a specific sequence of DNA that carries the instructions for a particular trait
Gene
genetic material found in the nucleus of cells
DNA (deoxyribonucleic acid)
differences that exist between individuals in a population
Variation
The group of islands where Darwin studied the finches
Galapagos islands
the process where an environmental factor acts on a population and results in some organisms having more offspring than others
Natural Selection
a thread-like structure composed of DNA and proteins that packages and organizes genes. Human cells normally contain 46 (23 from each parent)
Chromosomes
the reproductive cells, ova (eggs) in females and sperm in males. They combine to form the first cell of a new organism
Gamete
The organisms that are better suited to their environment survive the pressure of selective agents. This is often referred to as ‘Survival of the Fittest’.
Selection pressure
The name of the scientist that proposed another theory to Darwin, in which that organisms evolve through the inheritance of acquired characteristics
Lamarck
Preserved remains of ancient organisms, important evidence for evolution
Fossils
a trait expressed in appearance (upper case letter)
Dominant
a trait that recedes when the dominant is present (lower case letter)
Recessive
The process by which related species become more different over time due to adapting to live in different environments. Example: Darwin’s finches evolving different beak shapes based on their food sources.
Divergent evolution
when unrelated species evolve similar traits and adaptations due to living in similar environments or facing similar selective pressures. Example: sharks and dolphins
Convergent evolution
the formation of new species (usually due geographical isolation)
Speciation
different form of the same gene
Allele
a fertilised egg formed when two gametes combine
Zygote
Body parts in different species that have a similar structure due to common ancestry (closely related), even if they serve different functions (e.g., human arm and whale flipper).
Homologous structures
body parts of species that evolved independently with very different anatomies but similar functions (e.g., bird wings and insect wings)
Analogous structures
anatomical parts that were important in the species ancestors, but lost most or all of their original function through evolution (e.g., human appendix, wisdom teeth)
Vestigial structures
set of genes that an organism has
Genotype
set of traits that are displayed
Phenotype