Evolutionary thinking Flashcards
(30 cards)
What is the basic mechanism of natural selection?
Natural selection operates on variation in traits, competition for resources, and inheritance of advantageous traits, leading to adaptation over generations.
Explain how natural selection leads to adaptation.
Natural selection results in individuals with beneficial traits surviving and reproducing, passing on these traits to offspring, which leads to adaptation in the population over time.
What is the misconception about human evolution being ‘stopped’?
Humans continue to evolve. For example, resistance to malaria in Cape Verde due to the DARC gene and lactase persistence in Eurasia are recent examples of ongoing natural selection.
Why is ‘survival of the fittest’ a poor definition of evolution?
‘Survival of the fittest’ misrepresents natural selection. It implies that only the strongest survive, but fitness refers to reproductive success, not physical strength.
How have some human populations adapted to high altitudes?
Populations in high-altitude areas, like Tibetans, Ethiopians, and Andeans, have genetic adaptations like the EPAS1 gene mutation that allows them to thrive in low-oxygen environments.
What is the difference between ‘adaptations’ and ‘adjustments’?
Adaptations are genetic responses to natural selection, while adjustments are non-genetic, reversible responses to environmental conditions, like acclimatization.
What is the importance of genetic variation?
Genetic variation is essential for evolution as it provides the raw material for natural selection. It arises from mutations, recombination, and other genetic processes.
What is epigenetics and how does it differ from Lamarckian inheritance?
Epigenetics refers to changes in gene expression that do not involve changes in the DNA sequence. Unlike Lamarckian inheritance, these changes are reversible and do not directly alter genetic material.
What is the theory of gene-culture co-evolution?
Gene-culture co-evolution refers to the interplay between cultural practices and genetic evolution, like the spread of lactase persistence in populations with dairy farming cultures.
How do modern humans compare to our closest primate relatives?
Humans share about 99% of their DNA with other great apes, such as chimpanzees and bonobos, highlighting our close genetic relationship.
What is the biological species concept?
The biological species concept defines a species as a group of interbreeding populations that are reproductively isolated from other groups, focusing on genetic and reproductive isolation rather than appearance.
How does human genetic diversity compare to other species?
Humans have relatively low genetic diversity compared to other species, with about 99.9% of our DNA being identical between individuals.
What are some examples of recent human adaptations?
Examples include malaria resistance in Cape Verde and lactase persistence linked to dairy farming, both of which are recent genetic adaptations to environmental challenges.
What is the role of mutations in evolution?
Mutations are random changes in genetic material and are the ultimate source of genetic variation, providing the raw material for natural selection.
What is the significance of Mendelian inheritance in evolution?
Mendelian inheritance shows that traits are passed on in a particulate manner (dominant and recessive alleles), which laid the foundation for modern evolutionary genetics.
What is the difference between microevolution and macroevolution?
Microevolution refers to small, gradual changes within a species, while macroevolution involves larger-scale changes, such as speciation, occurring over longer timescales.
How does natural selection lead to speciation?
Natural selection can lead to speciation through reproductive isolation, where populations with different environmental pressures evolve distinct traits and cannot interbreed.
What is the theory of punctuated equilibria?
Punctuated equilibria proposes that evolution occurs in rapid bursts followed by long periods of stability, as opposed to gradual and continuous change over time.
What are some examples of phenotypic plasticity?
Phenotypic plasticity includes temporary responses to environmental factors, such as changes in body size or physiological responses to climate changes that are not genetically inherited.
How does human culture influence genetic evolution?
Human culture influences genetic evolution through practices like agriculture, diet, and medicine, which can exert selection pressures on human populations.
What is the role of cultural evolution in human adaptation?
Cultural evolution, such as the development of tools, language, and social structures, has allowed humans to adapt to diverse environments in ways that genetic evolution alone could not have facilitated.
How do cultural traits evolve?
Cultural traits evolve through social learning, with new innovations passing through generations and being modified to better fit the environment and social context.
What is the role of lactase persistence in human evolution?
Lactase persistence, the ability to digest milk into adulthood, evolved in populations that practiced dairy farming, demonstrating a gene-culture co-evolutionary process.
What is the significance of the EPAS1 gene in high-altitude populations?
The EPAS1 gene mutation helps high-altitude populations like Tibetans adapt to low-oxygen environments by regulating hemoglobin levels, reducing the risk of hypoxia.