Looking at the Big Ideas:
Identifying the Evolution Concepts
Much of what we teach about evolution can be associated with the
Teachers reflected on the primary concepts covered during this
session, using the document entitled Evolution Concepts K-12,
prepared by the UC Museum of Paleontology in 2002 for its Understanding
Evolution web project. The following concepts were selected.
History of life
Biological evolution accounts for diversity over long periods
- Through billions of years of evolution, life forms have continued
to diversify in a branching pattern, from single-celled ancestors
to the diversity of life on Earth today.
- Life forms of the past were in some ways very different from
living forms of today, but in other ways very similar.
Evidence of evolution
The long history of the Earth and the long history of changing
life are displayed in the many layers of sedimentary rock.
Form is often linked to function.
- Anatomical similarities of living things reflect common ancestry.
- The fossil record documents the sequential biodiversity of
Mechanisms of evolution
Evolution results from selection acting upon genetic variation
within a population.
- Individual organisms with advantageous traits are more likely
to survive and have offspring.
- Occupying new environments can provide both new selection pressures
and isolation, leading to speciation.
Adaptations are preserved in a population by natural selection.
Inherited characteristics affect the likelihood of an organism's
survival and reproduction.
- Depending on environmental conditions, inherited characteristics
may be advantageous, neutral, or detrimental.
- The amount of genetic variation within a population may affect
the likelihood of survival of the population; the less the available
diversity, the less likely the population will be able to survive
- Random factors affect the survival of individuals and of populations.
- Natural selection acts on individuals and populations in a nonrandom
- The number of offspring that survive to reproduce successfully
is limited by environmental factors.
- The proportion of individuals with advantageous characteristics
may increase due to their increased likelihood of surviving and
- Evolution does not consist of progress in a particular direction.
- Evolution may occur as a result of genetic drift.
Teachers raised the challenge
of conceptualizing deep time and cautioned about analogies and foot-shootings.
See teacher resources.
Return to: Lines of Evidence for Past Change
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