Lamarck vs Darwin

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Evolution Noun

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[ev-uh-loo-shun]

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Evolution

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The process of cumulative change in the heritable characteristics of biological populations over successive generations.

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Example: This image shows how different finch species, descended from a common ancestor, evolved unique beak shapes to adapt to different food sources on their islands.

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Natural Selection Noun

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[nach-er-uhl si-lek-shun]

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Natural Selection

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The process where organisms with favorable traits are more likely to reproduce, passing those traits to the next generation.

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Example: This image shows that giraffes with naturally longer necks can reach food and survive (✓), while those with shorter necks cannot (✗), illustrating natural selection.

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Acquired Characteristic Noun

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[uh-kwahrd kar-ik-ter-is-tik]

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Acquired Characteristic

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A non-heritable trait that an organism develops during its lifetime in response to environmental influences or its own activities.

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Example: A bodybuilder's large muscles are an acquired characteristic, developed through exercise and diet during their lifetime, not inherited from their parents.

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Adaptation Noun

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[ad-ap-tey-shun]

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Adaptation

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An inherited trait or characteristic that enhances an organism's ability to survive and reproduce in its specific environment.

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Example: Different finches developed unique beak shapes (adaptations) over time, allowing them to eat specific foods like seeds, insects, or fruit and survive.

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Fossil Noun

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[fos-uhl]

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Fossil

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The preserved remains, impression, or trace of an organism that lived in a past geological age, found in rock.

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Example: This diagram shows different fossils in distinct rock layers (strata), illustrating the fossil record. Older layers below contain different life forms than younger layers above.

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Allele Noun

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[uh-leel]

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Allele

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One of two or more alternative forms of a gene that arise by mutation and occupy the same relative position on homologous chromosomes.

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Example: An allele is a version of a gene. This image shows pairs of chromosomes with different allele combinations: two identical (homozygous) or two different (heterozygous).

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Mutation Noun

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[myoo-tey-shun]

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Mutation

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A permanent alteration in the nucleotide sequence of the genome of an organism, which can create new genetic variation.

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Example: A change (mutation) in a gene's code can cause the cell to build an abnormal protein, leading to a different physical trait.

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Genetic Diversity Noun

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[juh-net-ik di-vur-si-tee]

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Genetic Diversity

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The total number of different genetic characteristics present within the genetic makeup of a species or population.

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Example: This image shows many different breeds of dogs, which are all the same species, to illustrate the wide range of traits caused by genetic diversity.

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Artificial Selection Noun

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[ahr-tuh-fish-uhl si-lek-shun]

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Artificial Selection

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The intentional breeding of organisms by humans to propagate specific desired traits for human use or preference.

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Example: This diagram shows how humans have selectively bred dogs from a common wolf ancestor, resulting in many different breeds across the world.

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Directional Selection Noun

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[di-rek-shun-ul si-lek-shun]

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Directional Selection

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A mode of natural selection in which an extreme phenotype is favored, causing the allele frequency to shift over time.

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Example: This graph shows how a population changes when natural selection favors one extreme trait, causing the average trait of the population to shift in that direction.