Topics 9-11

Practice vocabulary flashcards covering behavior, macroevolutionary concepts, and phylogenetics based on lecture transcripts.

Evolution

A process of change at the population level from one generation to the next, often defined as descent with modification.

Descent with modification

A change at the population level from one generation to the next involving a trait that is variable and heritable.

Habituation

A type of learned behavior characterized by the loss of responsiveness to unimportant stimuli that are not associated with a specific response.

Classical Conditioning

A form of associative learning where a neutral signal is given before a physiological reflex to train an organism to associate the cue with a negative or positive reward.

Operant Conditioning

A form of associative learning involving reinforcement or punishment after a behavior, brought about directly by the object of the behavior through trial and error.

Observational Learning

A learned behavior where an organism acquires new actions by watching others and copying them, as seen in whooping cranes.

Innate behavior

A genetically determined and developmentally fixed behavior that occurs without prior experience and is often highly adaptive when mistakes are costly.

$fosB$ gene

A specific gene in mice that controls nurturing behavior; females homozygous for the mutant allele ($-/-$) ignore their pups.

Fixed Action Pattern

A fixed sequence of innate behaviors performed the same way every time that continues to completion once triggered by a simple stimulus.

Sign Stimulus

Also known as a Key Stimulus, this is the environment, internal, or external trigger that initiates a fixed action pattern.

Imprinting

A form of learning with both fixed and learned components where young animals associate a stimulus with a care-giver during a critical period.

Kinesis

Animal movement where the rate of movement or frequency of turning is altered due to the intensity of a stimulus, though the direction of movement is random.

Taxis

A non-random movement in response to a stimulus gradient; it is positive if towards the stimulus and negative if away from it.

Piloting

Movement relative to specific landmarks which requires the organism to have prior experience with the environment.

Navigation

Animal movement that involves the integration of both Orientation (using a compass direction) and Piloting (using landmarks).

Microevolution

The change in the frequency of alleles in a population from one generation to the next, which can be observed directly.

Macroevolution

The formation of new species occurring as microevolutionary changes accumulate over typically longer generational time-scales.

Ecotypes

Genetically distinct populations within a species that are adapted to different local environments.

Morphological species concept

The approach of distinguishing unique species based on physical characteristics and anatomical similarities.

Ecological species concept

The approach of defining unique species based on their ecological niche and unique set of habitat resources.

Phylogenetic species concept

The approach of defining unique species based on a shared common ancestor, often utilizing an analysis of molecular data like DNA sequences.

Biological species concept

The definition of a species as a group of related organisms that have the potential to interbreed and produce viable, fertile offspring.

Reproductive Isolating Mechanisms (R.I.M.s)

Barriers that promote reproductive isolation by preventing gene flow between diverging populations.

Reduced Hybrid Fertility

A postzygotic barrier where an interspecies hybrid is viable and survives to adulthood but is sterile, such as a mule.

Hybrid Breakdown

A postzygonic barrier where $F1$ hybrids are viable and fertile, but subsequent generations like $F2$ or $F3$ have decreased fitness.

Allopatric Speciation

The mode of speciation where a population forms a new species while geographically isolated from its parent population by a physical barrier.

Sympatric Speciation

The mode of speciation where a subset of a population forms a new species without geographic separation.

Polyploidy

A chromosomal alteration where an individual possesses more than $2$ complete sets of chromosomes, causing immediate reproductive isolation in sympatry.

Nodes

Branching points on a phylogenetic tree representing the point in time where populations diverged.

MRCA

An abbreviation for Most Recent Common Ancestor, representing the nearest node joining a specific clade together.

Maximum Parsimony

The phylogenetic criterion stating that the best tree is the one that requires the fewest evolutionary changes for all characters.

Homologous Structures

Structures in different species that evolved from the same feature in a common ancestor, even if they appear dissimilar or serve different functions.

Homoplasious Structures

Similar structures that arose independently through convergent evolution due to common selective pressures, rather than from a shared ancestor.

Monophyletic

The condition of a taxonomic group that includes the common ancestor and all of its descendants, essentially forming a complete clade.

Molecular Clock

A method used to date divergence events by applying a constant mutation rate to molecular data, such as the $16S$ ribosomal RNA gene.