Test #2 Flashcards
What are the three types of adaptations?
Structural, behavioural, physiological
Examples of structural adaptations include the shape of a bird’s beak, while behavioural adaptations might involve migration patterns, and physiological adaptations could relate to thermoregulation.
What is mimicry?
A form of adaptation where one species evolves to resemble another species
An example is the Viceroy butterfly, which mimics the appearance of the toxic Monarch butterfly.
What is camouflage?
An adaptation that allows an organism to blend in with its environment
For example, the stick insect resembles twigs to avoid predation.
How can variation lead to adaptation?
Variation allows certain individuals to have traits that provide a selective advantage
An example is the peppered moth, where darker moths had an advantage in polluted environments.
What is selective advantage?
A trait that improves an individual’s chances of survival and reproduction in a given environment
This can be seen in faster prey escaping predators.
What are the two types of selection discussed?
Natural selection and artificial selection
Natural selection occurs through environmental pressures, while artificial selection is driven by human choices.
Define fitness in an evolutionary context.
The ability of an organism to survive and reproduce in its environment
Often summarized as ‘survival of the fittest’.
Who contributed to the theories of evolution?
Darwin and Lamarck
Darwin proposed natural selection, while Lamarck suggested inheritance of acquired characteristics.
What are the sources of evidence for evolution?
Fossil record, biogeography, anatomy, embryology, DNA
These sources provide insights into how species have changed over time.
What are vestigial structures?
Remnants of organs or structures that had a function in an early ancestor
An example is the human appendix.
What is the difference between homologous and analogous structures?
Homologous structures arise from a common ancestor, while analogous structures serve similar functions but do not share a common ancestry
An example of homologous structures is the forelimbs of mammals, while wings of bats and insects are analogous.
What adaptations are seen in bird beaks?
Bird beaks have adapted to different food sources
For instance, finches on the Galápagos Islands have beaks shaped for cracking seeds or probing flowers.
List the five factors of microevolution.
Gene flow, genetic drift, non-random mating, mutation, selection
These factors can lead to changes in allele frequencies within a population.
What are the three types of natural selection?
Stabilizing, directional, disruptive
Stabilizing selection favors average traits, directional selection favors one extreme trait, and disruptive selection favors both extreme traits.
What is gene flow?
The transfer of alleles or genes from one population to another
This can occur through migration of individuals.
What is genetic drift?
Random changes in allele frequencies in small populations
This can lead to the loss of genetic diversity.
What is the founder effect?
A form of genetic drift that occurs when a small group establishes a new population
This can result in reduced genetic variation.
What is the bottleneck effect?
A sharp reduction in population size due to environmental events or disasters
This can drastically reduce genetic diversity.
What are reproductive isolation mechanisms?
Barriers that prevent mating and reproduction between different species
These can be pre-zygotic (before fertilization) or post-zygotic (after fertilization).
Give examples of pre-zygotic mechanisms.
Temporal isolation, behavioral isolation, mechanical isolation
These prevent different species from mating or producing viable offspring.
Give examples of post-zygotic mechanisms.
Hybrid inviability, hybrid sterility, hybrid breakdown
These occur after fertilization and affect the viability or fertility of hybrids.
What is the difference between sympatric and allopatric speciation?
Sympatric speciation occurs without geographic isolation, while allopatric speciation occurs due to geographic barriers
Sympatric speciation can occur through mechanisms like polyploidy in plants.
What is adaptive radiation?
The rapid evolution of diversely adapted species from a common ancestor
An example is the diversification of mammals after the extinction of dinosaurs.
Define gradualism in evolutionary terms.
The theory that evolution occurs slowly and steadily over long periods
This contrasts with punctuated equilibrium, which suggests rapid changes followed by long periods of stability.
