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Hi there! I'm Studyfin, your science tutor. Today we are going to explore how nature shapes living things over time!
Natural selection is the process where organisms with helpful traits are more likely to survive and reproduce. Over time, these helpful traits become more common in the population. It is important to know that natural selection changes populations over generations, not individual organisms.
For natural selection to happen, a population needs inherited variation, which means individuals have different genetic traits. There must also be overproduction of offspring, a struggle to survive, and differential reproductive success, meaning only some live to pass on their genes.
When populations of the same species are separated by barriers like rivers or mountains, they adapt to different environments. Over many generations, natural selection can lead to speciation, which is the creation of a brand new, distinct species.
A population of green and brown beetles lives in a forest. A drought turns the green leaves brown. Analyze how natural selection will produce change in this beetle population over several generations.
- Identify the inherited variation: The beetle population has two inherited color traits, green and brown.
- Evaluate environmental pressure: The drought changes the background color from green to brown, making green beetles easier for predators to spot.
- Determine survival and reproduction: Brown beetles are now camouflaged. They survive better and reproduce more than green beetles.
- Analyze population change: Over generations, the frequency of the brown gene increases, changing the population, while individual beetles do not change their own color.
