Natural Selection and Reproduction

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Chromosome Noun

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[kroh-muh-sohm]

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Chromosome

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A structure located inside the nucleus of a cell that contains the genes, which are instructions for traits.

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Example: A chromosome inside a cell nucleus contains genes, which are instructions for traits.

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Gene Noun

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[jeen]

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Gene

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A segment of a chromosome that serves as the instruction for making a specific protein molecule, which determines a trait.

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Example: A gene is shown as part of a chromosome within a cell, illustrating its role in DNA structure.

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Protein Molecule Noun

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[proh-teen mol-uh-kyool]

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Protein Molecule

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A type of large molecule made from instructions in genes that is responsible for an organism's specific traits.

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Example: Amino acids link to form peptides, which fold into a protein molecule, showing how proteins are built.

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Trait Noun

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[trayt]

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Trait

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A specific characteristic of an individual organism, which is determined by the protein molecules made from its genes.

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Example: The image shows how traits are linked to genes in chromosomes within a cell.

Front

Reproduction Noun

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[ree-pruh-duhk-shuhn]

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Reproduction

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The biological process by which new individual organisms, also known as offspring, are produced from their parents.

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Example: A hydra produces a new bud that grows into a new individual, illustrating asexual reproduction.

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Generation Noun

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[jen-uh-rey-shuhn]

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Generation

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A single step in the line of descent from an ancestor, such as the time between parents' and offspring's births.

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Example: A family tree diagram showing generations with symbols for males, females, and affected individuals.

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Variation Noun

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[vair-ee-ey-shuhn]

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Variation

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The differences in genes and the resulting traits that exist among individuals within the same species or population.

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Example: Different dog breeds show variation in traits like size and color within the same species.

Front

Mutation Noun

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[myoo-tey-shuhn]

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Mutation

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A random change in a gene that can alter the protein it codes for, which can potentially lead to a new trait.

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Example: A DNA strand with a highlighted change shows a mutation, explaining how genes can alter proteins.

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Population Noun

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[pop-yuh-ley-shuhn]

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Population

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A group of individual organisms of the same species that live and interact in the same geographic area.

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Example: A group of animals and plants living together in a pond ecosystem shows a population.

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Environment Noun

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[en-vahy-ruhn-muhnt]

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Environment

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All the living and nonliving conditions of the area where an organism lives, influencing its survival and reproduction.

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Example: The image shows an environment with animals, plants, and water, illustrating how living and nonliving elements interact.