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Evolution
- EVOLUTION is the gradual development of the inherited characteristic of a population over time through a process known as NATURAL SELECTION.
- This THEORY explains that all species of living things on Earth have gradually evolved from SIMPLE LIFE FORMS that first developed more that THREE BILLION YEARS AGO.
NATURAL SELECTION
- All organisms of a species show a large amount of variation in their PHENOTYPES (physical characteristics).
- Organisms within a species all COMPETE with EACHOTHER for RESOURCES such a food and shelter.
- The organisms which have BENEFICIAL phenotypes, are BETTER suited to their environment.
- This makes them MORE LIKELY TO SURVIVE and REPRODUCE.
- This makes them more likely to PASS ON THE BENEFICIAL GENES to their offspring.
- Over many generations, the beneficial characteristics become MORE COMMON in the species which results in the species EVOLVING.
An example of natural selection is with PEPPERED MOTHS:
- Light-colored peppered moths were common in Britain, resting on light-colored trees.
- Their coloration provided CAMOUFLAGE from predators like birds.
- Dark-colored moths (a result of a genetic mutation) were easier to spot and more likely to be eaten.
- During the Industrial Revolution, factories emitted soot and pollution, which DARKENED the tree bark.
- The ENVIRONMENT CHANGED, and now the light-colored moths stood out against the dark trees, making them MORE VISIBLE to predators.
- The dark-colored moths blended in better with the sooty bark and were LESS LIKELY to be eaten.
- Since dark moths were less likely to be eaten, they SURVIVED longer and had more chances to REPRODUCE.
- They PASSED ON THE GENES for dark coloration to their offspring.
- Over time, the number of dark moths increased because they had a higher survival rate.
Species
A species is a group of organisms capable of INTERBREEDING and producing FERTILE OFFSPRING.
When natural selection occurs, it is possible for two populations of ONE SPECIES to become so different in phenotype that they turn into TWO SPECIES.
This occurs when the two populations can no longer INTERBREED to form FERTILE OFFSPRING.
Evolution
- EVOLUTION is the gradual development of the inherited characteristic of a population over time through a process known as NATURAL SELECTION.
- This THEORY explains that all species of living things on Earth have gradually evolved from SIMPLE LIFE FORMS that first developed more that THREE BILLION YEARS AGO.
NATURAL SELECTION
- All organisms of a species show a large amount of variation in their PHENOTYPES (physical characteristics).
- Organisms within a species all COMPETE with EACHOTHER for RESOURCES such a food and shelter.
- The organisms which have BENEFICIAL phenotypes, are BETTER suited to their environment.
- This makes them MORE LIKELY TO SURVIVE and REPRODUCE.
- This makes them more likely to PASS ON THE BENEFICIAL GENES to their offspring.
- Over many generations, the beneficial characteristics become MORE COMMON in the species which results in the species EVOLVING.
An example of natural selection is with PEPPERED MOTHS:
- Light-colored peppered moths were common in Britain, resting on light-colored trees.
- Their coloration provided CAMOUFLAGE from predators like birds.
- Dark-colored moths (a result of a genetic mutation) were easier to spot and more likely to be eaten.
- During the Industrial Revolution, factories emitted soot and pollution, which DARKENED the tree bark.
- The ENVIRONMENT CHANGED, and now the light-colored moths stood out against the dark trees, making them MORE VISIBLE to predators.
- The dark-colored moths blended in better with the sooty bark and were LESS LIKELY to be eaten.
- Since dark moths were less likely to be eaten, they SURVIVED longer and had more chances to REPRODUCE.
- They PASSED ON THE GENES for dark coloration to their offspring.
- Over time, the number of dark moths increased because they had a higher survival rate.
Species
A species is a group of organisms capable of INTERBREEDING and producing FERTILE OFFSPRING.
When natural selection occurs, it is possible for two populations of ONE SPECIES to become so different in phenotype that they turn into TWO SPECIES.
This occurs when the two populations can no longer INTERBREED to form FERTILE OFFSPRING.
