IB Biology - Evolution & Adaptation

Flashcards for IB Biology - Evolution and Adaptation

Evolution (as defined in IB Biology)

Change in the heritable characteristics of a population over time. Acquired characteristics are not considered evolution.

Theory (in the context of evolution)

A well-substantiated explanation of some aspect of the natural world that can incorporate facts, laws, inferences, and tested hypotheses. Evolutionary theory is a pragmatic truth supported by extensive evidence.

Natural Selection

The mechanism driving evolutionary change, where individuals with advantageous heritable traits are more likely to survive and reproduce, leading to a shift in the population's genetic makeup.

Mutation

A change in the DNA sequence that introduces new alleles into a population, providing the genetic variation on which natural selection can act.

Sexual Reproduction

The process involving the fusion of gametes, resulting in offspring with new combinations of alleles, increasing genetic variation within a population.

Intraspecific Competition

Competition between individuals of the same species for limited resources, leading to differences in adaptation, survival, and reproduction, and thus, natural selection.

Heritability

The ability of a trait to be passed down from parents to offspring through genes. Only heritable traits contribute to evolutionary change.

Abiotic Factors

Non-living components of the environment (e.g., temperature) that act as selection pressures, influencing the survival and reproduction of individuals in a population.

Sexual Selection

A form of natural selection in which individuals with certain inherited characteristics are more likely than other individuals to obtain mates.

Homologous Structures

Structures in different species that have a similar underlying anatomy due to shared ancestry, even if their function may differ.

Convergent Evolution

The independent evolution of similar features in different lineages, resulting in analogous structures.

Analogous Structures

Structures in different species that have similar function but different evolutionary origins.

Speciation

The process by which new species arise from pre-existing species via splitting and divergence of populations.

Reproductive Isolation

The existence of biological factors (barriers) that impede members of two species from producing viable, fertile offspring.

Geographical Isolation

A form of reproductive isolation in which populations are separated by physical barriers, preventing gene flow and potentially leading to speciation.

Adaptation

A trait that enhances an organism's survival and reproduction in its environment.

Habitat

The natural environment where an organism lives; characterized by specific abiotic conditions.

Herbivore Adaptations

Specific traits that allow animals to efficiently feed on plants, such as specialized mouthparts or detoxification mechanisms.

Plant Defenses Against Herbivory

Traits that help plants avoid being eaten, such as thorns, toxic compounds, or other physical structures.

Predator Adaptations

Traits that allow predators to efficiently find, catch, and kill prey (e.g., sharp teeth, camouflage, speed).

Prey Adaptations

Traits that help prey animals avoid being caught and eaten (e.g., camouflage, speed, defensive chemicals).

Plant Adaptations for Light Harvesting

Structures and strategies used by plants to maximize light capture for photosynthesis, such as leaf arrangement, height, or tolerance of shade.

Plant Adaptations to Arid Climates

Traits that allow plants to withstand drought conditions, such as deep roots, water storage tissues, reduced leaf surface area, or the ability to conserve water efficiently.

Animal Adaptations to Arid Climates

Traits that allow animals to survive in desert environments, such as nocturnal behavior, efficient water conservation, specialized kidneys, or tolerance of high body temperatures.

Plant Adaptations for Pollination

Strategies used by plants to attract pollinators, such as bright colors, nectar production, scent, or specialized flower shapes.

Plant Adaptations for Seed Dispersal

Traits that enhance seed dispersal, such as wind dispersal mechanisms (e.g., wings, plumes), animal dispersal (e.g., fleshy fruits, hooks), or self-dispersal mechanisms (e.g., explosive seed pods).

Coevolution

The process by which two species evolve in response to each other, resulting in reciprocal adaptations (e.g., predator-prey relationships, plant-herbivore interactions, mutualistic relationships).

Ecological Niche

The range of physical and biological conditions in which a species can survive and reproduce, including resource availability, temperature, and interactions with other species.

A relationship between two species in which both species benefit (e.g., pollination, seed dispersal, mycorrh