Master this deck with 21 terms through effective study methods.
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Speciation is the process by which new species arise. It can occur through mechanisms such as allopatric speciation, where populations are geographically isolated and undergo genetic changes due to different selection pressures or genetic drift.
Allopatric speciation occurs when populations are separated by geographical barriers, leading to genetic divergence. Sympatric speciation occurs within the same geographical area, often due to behavioral changes, polyploidy, or ecological niches that reduce gene flow.
Convergent evolution is the process where unrelated species evolve similar traits due to similar environmental pressures. An example is the evolution of wings in bats and birds, which serve the same function but evolved independently.
Adaptive radiation is the rapid evolution of diversely adapted species from a common ancestor when new niches become available. An example is Darwin's finches, which evolved different beak shapes to exploit various food sources on the Galápagos Islands.
Ecological succession is the process of change in species composition in an ecosystem over time. It can create new niches and alter selection pressures, leading to divergent evolution and the emergence of new species.
Species with low genetic diversity are at a higher risk of extinction because they have less ability to adapt to environmental changes and are more susceptible to harmful mutations.
Harmful mutations are genetic changes that negatively affect an organism's fitness. In populations with low genetic diversity, these mutations can spread more easily, as there are fewer alternative alleles to counteract their effects.
Succession begins with pioneer species like lichen that colonize bare rock. They trap moisture and soil, allowing mosses to grow. Mosses further weather the rock, enabling ferns to establish, leading to a more complex ecosystem over time.
Ecosystems can be destabilized by physical factors such as floods, fires, volcanic eruptions, and human activities like logging and farming, which disrupt the biotic and abiotic interactions that maintain stability.
A climax community is a stable and mature ecological community that undergoes little change in species composition. It is reached when the ecosystem is in equilibrium, and only disturbances can alter its structure.
Biotic interactions (like predation, competition, and symbiosis) and abiotic factors (such as climate and soil type) work together to create a balanced ecosystem. This balance allows for the coexistence of diverse species and resilience to changes.
Darwin's finches are significant because they illustrate adaptive radiation, showing how species can evolve different traits in response to varying environmental pressures and available resources on the Galápagos Islands.
Environmental changes can create new niches and alter selection pressures, leading to divergent evolution or adaptive radiation as species adapt to new conditions or resources.
Selection pressures can be abiotic (like climate and geography) or biotic (like competition and predation). These pressures can lead to adaptations that drive speciation in isolated populations.
Genetic drift is the random change in allele frequencies in a population, which can lead to speciation, especially in small, isolated populations where certain traits may become fixed or lost purely by chance.
Mutations are changes in DNA that can introduce new genetic variation into a population. While many mutations are neutral or harmful, beneficial mutations can provide a selective advantage and contribute to evolution.
Human activities such as deforestation, urbanization, and agriculture can disrupt natural succession processes, leading to altered ecosystems that may not recover to their original state.
Primary succession occurs in lifeless areas where soil has not yet formed, while secondary succession occurs in areas where a disturbance has destroyed an existing community but left the soil intact.
Examples of species with low genetic diversity include the cheetah, which has experienced a genetic bottleneck, and the Florida panther, which has a limited gene pool due to habitat fragmentation.
Ecological succession can lead to increased biodiversity as new species colonize an area, fill different ecological niches, and create a more complex and stable ecosystem over time.
The 'Five Fingers of Evolution' is a mnemonic that represents the mechanisms of evolution: mutation, gene flow, genetic drift, non-random mating, and natural selection, which together explain how populations evolve over time.