Glossary
Adaptation
A trait or characteristic that has evolved through natural selection to help an organism survive and reproduce more effectively in its specific environment.
Example:
The thick fur of a polar bear is an adaptation that helps it survive in extremely cold Arctic environments.
Charles Darwin
A renowned naturalist who proposed the theory of evolution by natural selection, explaining how species adapt and change over time.
Example:
Charles Darwin's observations of finches on the Galapagos Islands provided crucial evidence for his theory of how species evolve through adaptation.
Chromosomes
Thread-like structures found within the nucleus of a cell, composed of DNA and proteins, that carry genetic information in the form of genes.
Example:
Humans typically have 23 pairs of chromosomes, with one set inherited from each parent, determining traits like eye color and height.
Genes
Specific segments of DNA located on chromosomes that serve as the basic units of heredity, coding for particular traits or proteins.
Example:
A specific gene might be responsible for producing melanin, which determines hair and skin pigmentation.
Mutations
Random, spontaneous changes in the DNA sequence of a gene or chromosome, which can lead to new traits or variations.
Example:
A genetic mutation might cause an individual to have a unique ability, like resistance to a certain disease, which could then be passed on.
Natural Selection
The evolutionary process where traits that enhance an organism's survival and reproductive success in a particular environment are more likely to be passed on to subsequent generations.
Example:
Over many generations, giraffes with longer necks were better able to reach leaves on tall trees, leading to natural selection favoring the trait of long necks in the giraffe population.
Survival of the Fittest
A phrase often associated with natural selection, referring to the idea that organisms best suited to their environment are more likely to survive and pass on their genes.
Example:
In a changing climate, species that can quickly adjust their behaviors or physiology demonstrate survival of the fittest by outcompeting those that cannot adapt.