[Sem 2] Biology Evolution Flashcards
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Genetic Diversity
The range of genetic differences within a species.
Importance of Genetic Diversity
Allows adaptation to environmental changes, increasing survival chances.
Causes of Genetic Diversity
Mutations, sexual reproduction, and gene flow between populations.
Consequences of Low Genetic Diversity
Reduces adaptability and increases extinction risk when faced with environmental changes.
Darwin’s Theory of Natural Selection
Process where organisms better suited to their environment survive and reproduce.
Natural Selection Steps
- Variation exists within a population.
- Selection pressures favour certain traits.
- Organisms with advantageous traits survive and reproduce.
- Over generations, beneficial traits become more common
Selection Pressure
Environmental factors that affect an organism’s survival and reproduction, e.g. predators, climate.
Lamarck’s Theory of Inheritance of Acquired Characteristics
Traits developed during an organism’s life (like muscle strength) are passed to offspring. Currently disproven.
Physiological Adaptation
Internal functions aiding survival (e.g. camels conserving water).
Structural Adaptation
Physical traits aiding survival (e.g. thick fur in arctic animals).
Behavioural Adaptation
Actions improving survival (e.g. birds migrating).
Genetic Drift
Random changes in allele frequencies, more impactful in small populations. E.g. natural disasters, habitat loss
Bottleneck Effect
Sharp reduction in population size due to an event (e.g., earthquake).
Impact of Bottleneck Effect
Loss of genetic diversity, leaving a population vulnerable to future changes.
Convergent Evolution
Unrelated species evolve similar traits due to similar environmental pressures. E.g. wings in both birds and insects.
Divergent Evolution
Related species evolve different traits due to different environmental pressures. E.g. Darwin’s finches developing different beaks.
Primates Characteristics
Opposable thumbs, binocular vision, large brains (e.g., monkeys, apes).
Hominoids Characteristics
Larger body size, no tail, complex brain (e.g., gorillas, chimpanzees).
Hominins Characteristics
Bipedalism, advanced tool use, smaller canine teeth (e.g., humans, ancestors of humans).
Classification Levels
Kingdom → Phylum → Class → Order → Family → Genus → Species
(Largest to smallest group; each step adds more specific traits).
Biodiversity
Variety of life on Earth at genetic, species, and ecosystem levels. Supports ecosystems, adapts to changes, and enhances survival.
Adaptive Evolution
Evolution that increases fitness in a specific environment.
Adaptive Radiation
Rapid evolution of many species from a common ancestor in diverse environments.
Mutation
Change in DNA that can lead to variation and sometimes new traits.
