UCONN BIOL 1108 Exam 1

phylogeny

the history of descent with branching

node

in phylogenetic trees, the point where a branch splits, representing the common ancestor from which the descendant species diverged

nodes can be rotated without changing ________________________

evolutionary relationships

phylogenetic trees

provide hypotheses of evolutionary relationships

phylogenetics

the study of evolutionary relationships among organisms

taxonomy

the classification of organisms

phylogenetic tree

a diagrammed hypothesis about the evolutionary history, or phylogeny, of a species

a phylogenetic tree is a ______________________________ of the evolutionary relationships among organisms

reasoned hypothesis

the search for sister groups lies at the heart of _______________

phylogenetics

sister groups

groups that are more closely related to each other than either of them is to any other group

monophyletic group

includes of a common ancestor and all of its descendants

taxon

(plural, taxa) all the species in a taxonomic entity such as a family or genus

paraphyletic group

includes a common ancestor and some, but not all, of its descendants

polyphyletic group

does not include the common ancestor

taxonomic classifications are ________________________ and _______________________

information storage, retrieval systems

classification hierarchy

domain, kingdom, phylum, class, order, family, genus, species

three domains of life

Eukarya, Bacteria, Archaea

homology is similarity by _____________________

common descent

characters

the anatomical, physiological, or molecular features of an organism that varies among closely related species

character states

the observed condition of a character, such as presence or absence of lungs or arrangement of petals

homologous

characters that are similar because of descent from a common ancestor

analogous

similarities due to independent adaptation by different species

shared derived characters enable biologists to reconstruct _______________________

evolutionary history

synapomorphies

shared derived characters

cladistics

phylogenetic reconstruction on the basis of synapomorphies

the _________________ is often favored among multiple possible trees

simplest tree

parsimony

choosing the simplest hypothesis to account for a given set of observations

molecular data complement comparative morphology in reconstructing ________________________

phylogenetic history

phylogenetic trees can help solve ________________________

practical problems

_________________ provide unique information

fossils

fossils provide a selective record of _______________

past life

trace fossils

a track or trail, such as a dinosaur track or the feeding trails of snails and trilobites, left by an animal as it moves about or burrows into sediments

molecular fossils

sterols, bacterial lipids, and some pigment molecules, which are relatively resistant to decomposition, that accumulate in sedimentary rocks and document organisms that rarely form conventional fossils

_______________________ indicate the age and environment settling of fossils

geological data

geologic timescale

the series of time divisions that mark Earth's long history

fossils can contain unique combinations of __________________

characters

rare ____________________ have altered the course of evolution

mass extinctions

mass extinctions

a catastrophic drop in recorded diversity, which has occurred five or more times in the past 541 million years

Tiktaalik

"in-betweener"

Tiktaalik showed mixed traits from each of the major groups ____________ and _____________ it existed

before, after (fins, scales, gulls, wrist bones, fingers, true neck, amphibian skull)

_____________________ and ____________________ complement each other

phylogeny, fossils

agreement between phylogenies and fossil record provides strong _________________________________

evidence of evolution

a _________________________ is a reasoned hypothesis of the evolutionary relationships among organisms

phylogenetic tree

a phylogenetic tree is built on the basis of __________________________________________

shared derived characters

the fossil record provides direct evidence of ________________________________

evolutionary history

phylogeny and fossils provide _________________ and ____________________ evidence of evolution

independent, corroborating

___________________________________ is the key to the biological species concept

reproductive isolation

reproductive isolation is caused by barriers to reproduction ____________ or ________________ egg fertilization

before, after

___________________ underlies the diversity of life on earth

speciation

speciation can occur with or without _________________

natural selection

speciation

the process that produces new and distinct forms of life

species plot

a graphical representation of characteristics of individuals

species

the fundamental evolutionary unit

______________ are reproductively isolated from other species

species

biological species concept (BSC)

the concept that species are groups of actually or potentially interbreeding populations that are reproductively isolated from other such groups

the ____ is the most widely used and accepted definition of species

BSC

The BSC is more useful in __________ than in practice

theory

morphospecies concept

the idea that members of the same species usually look like each other more than like other species

the BSC does not apply to ___________ or __________ organisms

asexual, extinct

_____________ and __________ complicate the BSC

ring species, hybridization

ring species

species with populations that are reproductively but not genetically isolated

hybridization

interbreeding between two different varieties or species

limitations of the BSC and mophospecies concept

1. difficult to apply in real world

2. cannot be applied to asexual or extinct organisms

3. does not account for genetic exchange in ring species

4. does not account for hybridization in plants

____________ and _____________ can extend the BSC

ecology, evolution

ecological niche

a complete description of the role a species plays in its environment

ecological species concept (ESC)

the idea that there is a one-to-one correspondence between a species and its niche

phylogenetic species concept (PSC)/evolutionary species concept (EvSC)

the idea that members of a species all share a common ancestry and a common fate

___________________ isolating factors occur before egg fertilization

pre-zygotic

___________________ isolating factors occur after egg fertilization

post-zygotic

pre-zygotic isolating factors

behavioral, physical, temporal (time), ecological (space)

post-zygotic isolating factors

genetic incompatibility, sterile offspring

behaviorally isolated

individuals mate only with other individuals based on specific courtship rituals, songs, or other behaviors

gametic isolation

incompatibilities between the gametes of two different species

mechanical incompatibility

structural configuration of the genitalia that prevents mating with another species

temporal isolation

pre-zygotic isolation between individuals that are reproductively active at different times

geographical isolation

spatial segregation of individuals

ecological isolation

pre-zygotic isolation between individuals that specialize ecologically in different ways

genetic incompatibility

genetic dissimilarity between two organisms, such as different number of chromosomes, that is sufficient to act as a post-zygotic isolating factor

speciation is a by-product of the genetic divergence of ________________________

separated populations

partially reproductively isolated

describes populations that have not yet diverged as separate species but whose genetic differences are extensive enough that the hybrid offspring they produce have reduced fertility or viability compared with offspring produced by crosses between individuals within each population

______________ speciation is speciation that results from the geographical separation of populations

allopatric

allopatric

"different place"

allopatric populations

populations that are geographically separated from each other

subspecies

allopatric populations that have yet to evolve even partial reproductive isolation but which have acquired population-specific traits

_______________ and ________________ can isolate populations from each other

dispersal, vicariance

dispersal

the process in which some individuals colonize a distant place far from the main source populations

peripatric speciation

a specific kind of allopatric speciation in which a few individuals from a mainland population disperse to a new location remote from the original population and evolve separately

adaptive radiation

a period of unusually rapid evolutionary diversification in which natural selection accelerates the rates of both speciation and adaptation in a single lineage

_______________ is speciation that occurs in response to speciation in another species

co-speciation

co-speciation

a process in which two groups of organisms speciate in response to each other and at the same time

sympatric populations - those not geographically separated - may undergo ________________

speciation

sympatric

"same place"

speciation can occur ________________

instantaneously

instantaneous speciation

speciation that occurs in a single generation

polyploidy

multiple chromosome sets

most speciation is thought to happen ________________

allopatrically

variance-derived speciation

a change in the physical environment causes allopatry

peripatric speciation followed by _______________

adaptive radiation

natural selection does not always lead to __________________

speciation

reinforcement of reproductive isolation (reinforcement)

the process by which diverging populations undergo natural selection in favor of enhanced pre-zygotic isolation to prevent the production of inferior hybrid offspring