2C3 Evolutionary processes in living things Flashcards
Understand mutations, adaptations, natural selection, and evolution.
What is natural selection?
The process by which organisms better adapted to their environment tend to survive and produce more offspring.
This concept forms the cornerstone of Darwinian evolution, explaining how heritable traits that confer advantages in survival and reproduction become more common in a population over generations.
Who proposed the theory of natural selection?
Charles Darwin and Alfred Wallace.
This was proposed in 1858.
Name the five steps of natural selection.
- Variation in traits.
- Overproduction of offspring.
- Struggle for existence (competition for resources).
- Differential survival (survival of the fittest).
- Differential reproduction (those who survive reproduce).
What did Darwin mean by “survival of the fittest”?
Those best adapted to their environment (fittest) are more likely to survive and reproduce successfully, passing on their alleles to the next generation.
In evolutionary terms, “fitness” refers to an organism’s ability to survive and reproduce, passing on advantageous traits to offspring. It does not exclusively denote physical prowess or strength.
Give an example of natural selection in action.
Darwin’s finches in the Galapagos Islands, which adapted different beak shapes for various food sources.
How did peppered moths in Britain demonstrate natural selection?
By changing wing colors from white to black due to industrial pollution, which helped them camouflage and avoid predation.
What is evolutionary adaptation?
How organisms change over time to better fit their environment, enhancing survival and reproduction.
Adaptations can occur through natural selection, genetic drift, and other evolutionary mechanisms, resulting in physical, physiological, or behavioral changes that improve an organism’s chances of survival.
Name three types of evolutionary adaptation.
- Behavioral
- Physiological
- Structural (Anatomical)
Describe a behavioral adaptation in penguins.
Emperor penguins huddling together for warmth during Antarctic winters.
Give an example of physiological adaptation in penguins.
Male emperor penguins reducing their heart rates during long dives for food.
Describe structural adaptation in penguins.
Penguins have streamlined bodies and flippers adapted for efficient swimming in water.
Structural adaptations are physical changes in an organism that directly affect its form and function in its environment.
What are adaptive traits?
Genetic characteristics that enhance an organism’s survival and reproduction.
Differentiate between analogous and homologous structures.
- Analogous structures have similar functions but different evolutionary origins.
- Homologous structures have similar evolutionary origins but may serve different functions.
Provide an example of analogous structures.
Bird and insect wings both evolved for flight but have different underlying structures.
Give an example of homologous structures.
The forelimbs of humans, whales, and bats share a common ancestor despite their different functions.
Explain how genetic traits influence natural selection.
Those that enhance survival are more likely to be passed on, shaping future generations.
Define convergent evolution and give an example.
- Occurs when unrelated species develop similar traits due to similar environmental pressures.
- Example - dolphins and sharks both evolved streamlined bodies for swimming.
What is allopatric speciation?
Occurs when populations of a species are geographically isolated, leading to genetic divergence.
An example is when a river changes course, separating a population of fish into two groups that cannot interbreed. Over time, these groups evolve independently, potentially leading to the formation of two distinct species.
Explain sympatric speciation.
Occurs within the same geographical region, often due to niche specialization or sexual selection.
A simple example of sympatric speciation is apple maggot flies evolving to prefer different types of fruit (apples vs. hawthorns), leading to reproductive isolation and the formation of new species.
What are niches in the context of evolution?
These are specific roles or positions that an organism occupies in its ecosystem, influencing its adaptations and evolution.
