Comprehensive Evolution, Ecology, and Phylogenetics Concepts for Biology

What did James Hutton theorize?

The concept of gradualism.

What does the concept of uniformitarianism state?

The natural laws that operate in the present have always been in operation.

Which scientist first suggested a mechanism for evolution?

Jean-Baptiste Lamarck.

How is evolution defined?

Changes in alleles over time in a population.

Who was the economist that influenced Darwin?

Thomas Malthus.

What were Thomas Malthus's observations?

Natural resources are limited and organisms have to compete for resources.

What did Carolus Linnaeus develop?

Binomial nomenclature.

Why is binomial nomenclature significant?

It allows for a systemic classification of organisms.

How is population defined?

A group of the same species that are interbreeding and sharing a gene pool.

Which scientist theorized the concept of uniformitarianism?

Charles Lyell.

Which scientist proposed the natural selection mechanism of evolution?

Charles Darwin.

What is natural selection?

An evolutionary mechanism proposed by Darwin and Wallace by which organisms better adapted to their environment tend to survive and produce more offspring.

What are homologous structures?

Organs or skeletal elements of organisms that suggest their connection to a common ancestor.

What were Darwin's four major observations?

Overproduction, unequal ability to survive and reproduce, variation among traits, and non-random survival/reproduction.

What does it mean to be fit from a biological perspective?

An organism that has a lot of offspring.

What does the gradualism hypothesis state?

Evolution proceeds chiefly by the accumulation of gradual changes.

What are vestigial structures?

Structures in organisms that have lost most/all of their original function in the course of evolution.

True or False: Bacteria, Archaea, and Eukarya all evolved from a common ancestor.

TRUE.

True or False: Natural selection creates new traits in organisms.

False; natural selection edits traits already present.

What are the two ways in which a population can end up very small?

The bottleneck effect and the founder effect.

True or False: Rapid asexual reproduction often has frequent mutations.

TRUE.

What is consanguineous mating?

Mating between individuals who are closely related.

What does p represent in the Hardy-Weinberg equation?

Dominant homozygous frequency.

What is gene flow and what does it result in?

Movement of genetic information between populations, reducing differences over time.

What is a fixed allele?

An allele that is the only variant that exists for that gene in all the population.

What does q represent in the Hardy-Weinberg equation?

Recessive homozygous frequency.

True or False: The recombination of chromosomes during sexual reproduction leads to new alleles.

False; the only source of new alleles are mutations.

What is the founder effect?

The loss of genetic variation when a new population is established by a very small number of individuals.

What is stabilizing selection?

Type of natural selection where the population mean stabilizes on a particular non-extreme trait.

What does pq represent in the Hardy-Weinberg equation?

Heterozygous frequency.

What is a gene pool?

All alleles of all genes in a population.

What is non-random mating?

When the probability of mating is not the same for all possible pairs.

What is allele frequency?

Relative proportion of a specific allele in a population.

True or False: Hardy-Weinberg equilibrium describes a population that is evolving.

False; it describes a population that is not evolving.

What is directional selection?

Mode of natural selection where a phenotype is favored, shifting allele frequency over time.

What is a silent mutation?

Change in DNA sequence without a change in the amino acid or function of the protein.

What is the difference between the two Hardy-Weinberg formulae?

One yields the frequency of organisms, the other yields the frequency of alleles.

What is random mating?

A situation where all individuals of one sex are equally potential partners of all members of the opposite sex.

What is disruptive selection?

Type of natural selection that selects against the average individual in a population.

What is genetic drift?

Variation in the relative frequency of different genotypes in a small population.

What is the bottleneck effect?

Sharp reduction in population size due to environmental effects.

What effect would the lack of gene flow have on a population?

Accumulation of differences between isolated populations.

True or False: Allele frequencies in a gene pool tend to stay constant until altered by an outside force.

TRUE.

What are the differences between microevolution and macroevolution?

Microevolution refers to shifts in allele frequencies; macroevolution results in significant changes transcending species boundaries.

What is speciation?

The formation of new and distinct species in the course of evolution.

What is habitat isolation?

Prezygotic isolation mechanism by which habitat preferences lower mating probability.

What is hybrid breakdown?

Postzygotic isolation mechanism where first-generation hybrids produce feeble or sterile offspring.

How is a species defined according to the ecological species concept?

Species are defined based on their niche.

What are hybrids?

Offspring resulting from the sexual reproduction of different species.

What are the five prezygotic isolation mechanisms?

Habitat isolation, temporal isolation, behavioral isolation, mechanical isolation, and gametic isolation.

What is sympatric speciation?

Speciation that occurs without physical separation of the populations.

What is the type of speciation that occurs when two groups of the same species live in the same geographic location but evolve differently?

Sympatric speciation

How is a species defined according to the biological species concept?

A species is a group of populations whose members naturally interbreed and produce viable, fertile offspring.

What are the limitations of the ecological species concept?

The complex interactions which define the organism(s) of interest must be well understood.

What is temporal isolation?

A prezygotic reproductive barrier mechanism where species are prevented from mating because they breed at different times.

How are species differentiated according to the morphological species concept?

By groups of physical traits that are unique to each species.

What is allopatric speciation?

Speciation that occurs when two populations of the same species become isolated due to geographical changes.

What are the three postzygotic isolation mechanisms?

Reduced hybrid viability, reduced hybrid fertility, and hybrid breakdown.

What is reproductive isolation?

A collection of mechanisms that prevent members of different species from producing offspring.

What are the limitations of the biological species concept?

It can only define species that are alive and undergo sexual reproduction.

What is behavioral isolation?

A prezygotic isolation mechanism where two species don't interbreed due to differences in courtship rituals.

What is reduced hybrid viability?

A postzygotic isolation mechanism where offspring have a low potential to survive due to incompatible genetics.

What are the limitations of the morphological species concept?

The physical traits used to differentiate species must be well defined and agreed upon.

Which species concepts can define extinct and/or asexually reproducing species?

Morphological species concept and ecological species concept.

What is mechanical isolation?

A prezygotic isolation mechanism where morphological differences prevent mating.

What is gametic isolation?

A prezygotic isolation mechanism where fertilization is inhibited due to differences in gametic cells.

What is reduced hybrid fertility?

A postzygotic isolation mechanism where offspring are healthy but sterile.

Which phenomena can lead to sympatric speciation?

Disruptive selection, polyploidy, sexual selection, and habitat differentiation.

What is the difference between taxonomy and phylogeny?

Taxonomy classifies organisms into categories, while phylogeny reflects their evolutionary history.

What is a phylogenetic tree?

A hypothetical diagram that represents evolutionary relationships among organisms.

What is the phylogenetic species concept?

The concept that a species is the smallest set of organisms distinguishable on a phylogenetic tree.

What is a dichotomy in phylogeny?

A branch point on a tree that has two immediate descendants.

What is a monophyletic group (clade)?

A group that includes an ancestor and all its descendants.

What is an extant species?

A species that is still alive.

What is the difference between homologous traits and analogous traits?

Homologous traits are derived from a common ancestor; analogous traits are similar due to convergent evolution.

What does a rooted tree represent?

The most recent common ancestor of all taxa on the tree.

What is a basal taxon?

A lineage that evolved early from the root and from which no other branches have diverged.

What are shared derived traits?

Characteristics unique to a particular clade.

What are sister taxa?

Any two taxa derived from an immediate common ancestor.

What is the difference between a monophyletic group and a paraphyletic group?

A monophyletic group includes the ancestor and all descendants; a paraphyletic group includes the ancestor and some but not all descendants.

What is convergent evolution?

The process where unrelated organisms independently evolve similar traits.

What is a polytomy?

A branch point on a phylogenetic tree with more than two groups.

What is cladistics?

A method of biological classification based on the most recent common ancestor.

What does a node represent on a phylogenetic tree?

The divergence of two lineages from a common ancestor.

What is the difference between the ingroup and the outgroup?

The ingroup refers to the taxa being studied; the outgroup refers to the taxa that diverged before the lineage being studied.

What is a polyphyletic group?

A group where organisms are grouped together but do not share an immediate common ancestor.

What is the difference between ancestral traits and derived traits?

Ancestral traits are homologous within a group; derived traits are present in an organism but absent in the most recent common ancestor.

What is the difference between proximate and ultimate causation?

Proximate causation refers to immediate causes; ultimate causation refers to underlying mechanisms.

What is a circannual rhythm?

A biological rhythm that occurs at intervals of approximately one year.

What is the difference between classical conditioning and operant conditioning?

Classical conditioning associates an involuntary response with a stimulus; operant conditioning associates a voluntary behavior with a reward.

What is spatial learning/memory?

The process by which an organism acquires a mental representation of its environment.

What is a fixed action pattern?

An instinctive behavioral response to a sign stimulus.

How is communication defined?

The transmission and reception of mutually recognizable signals.

What is circadian rhythm?

A natural, internal process that regulates the sleep-wake cycle, repeating approximately every 24 hours.

What is behavioral imprinting?

Establishment of a long-lasting behavioral response to a particular individual or object.

What does it mean if an animal is promiscuous?

It has no strong pair bonds.

True or False: An organism can prevent a fixed action pattern from proceeding to completion.

False; once initiated, it will proceed to completion.

What type of conditioning involves learning through rewards or punishments?

Operant conditioning.

What is the difference between polygyny and polyandry?

Polygyny is when one male has multiple female mates; polyandry is when one female has multiple male mates.

What is a sign stimulus?

A stimulus that provokes a fixed action pattern response.