patterns of evolution. macroevolution/microevolution allele gene both involve changes in allele...

Patterns of EvolutionPatterns of Evolution

Macroevolution/MicroevolutionMacroevolution/Microevolution

Both involve changes in alleleallele frequencies in genegene pools

Both work through the same basicsame basic processes

The differencedifference is largely one of approach approach and scalescale

Each offers offers different insightsinsights into the evolutionevolution process

Macroevolution/MicroevolutionMacroevolution/Microevolution

Macroevolution- One genus or familyfamily evolves into another….due to largelarge scale changes that take place over longlong periods of time.

Microevolution- SmallSmall scale changes within a species to produce new varieties or speciesspecies in a relatively shortshort amount of time.

Macroevolution/MicroevolutionMacroevolution/Microevolution

Macroevolution1. Large-scaleLarge-scale changes

in gene frequencies 2. Occurs over a longer longer

(geological) time time period period

3. Occurs at or above the level of specieslevel of species in separatedseparated gene pools

4. Consists of extendedextended

microevolutionmicroevolution

Microevolution1. Small-scaleSmall-scale changes

in gene frequencies

2. Occurs over a few few generationsgenerations

3. Occurs within a within a speciesspecies or population in samesame gene pool

4. Refers to smallersmaller

evolutionaryevolutionary changes

Macroevolution/MicroevolutionMacroevolution/Microevolution

Macroevolution5. Has notnot been

directly observedobserved

6. Evidence based on

remnants remnants of the past past

7. More More controversial 8. Example: Birds from

reptiles

Microevolution5. ObservableObservable

6. Evidence produced

by experimentationexperimentation

7. Less Less controversial 8. Example: Bacterial

resistance to

antibiotics

Macroevolution/MicroevolutionMacroevolution/Microevolution

Dog Variability When bred for certain traits, dogs become different and distinctive. This is a common example of microevolution—changes in size, shape, and color—or minor genetic alterations.  It is not macroevolution: an upward, beneficial increase in complexity. 

Macroevolution/MicroevolutionMacroevolution/Microevolution

Patterns of MacroevolutionPatterns of Macroevolution

A. Mass Extinctions

B. Adaptive Radiation

C. Convergent Evolution

D. Coevolution

E. Gradualism

F. Punctuated Equilibrium

These are theories/models of evolution

Mass ExtinctionsMass Extinctions

Event in which manymany types of living things became extinct at the same timeat the same time.

Period in which huge numbers of speciesspecies disappeareddisappeared.

Whole ecosystemsecosystems were wiped outwiped out Left habitatshabitats/niches openopen Resulted in burst of evolutionburst of evolution of new

species in new habitat Disrupted energy flowenergy flow throughout the

biosphere and caused food websfood webs to collapsecollapse

Mass ExtinctionsMass Extinctions

Possible causes– AsteroidsAsteroids hitting earth– VolcanicVolcanic eruptions– Continental driftdrift– Sea levelsSea levels changing

Mass Mass ExtinctionsExtinctions

Is an on-going process

Adaptive RadiationAdaptive Radiation

The evolution of an ancestral speciesancestral species, which was adaptedadapted to a particular way of life, into many diversemany diverse species, each adapted to a different habitatdifferent habitat

Many new speciesspecies diversify from a common ancestorcommon ancestor .

The branching outbranching out of a population through variationvariation.

The new species livelive in differentdifferent ways thanthan the original original species did.

Adaptive RadiationAdaptive Radiation

Adaptive RadiationAdaptive Radiation

Adaptive RadiationAdaptive Radiation

Diversity in anoles

is most strikingin the

Caribbean islands

Adaptive RadiationAdaptive Radiation

Hawaiian honeycreepers

Variation in color and bill shape is related to their habitat and diet

Convergent EvolutionConvergent Evolution

OppositeOpposite of divergent evolutiondivergent evolution (adaptive radiation)

UnrelatedUnrelated organismsorganisms independently evolve evolve similaritiessimilarities when adapting to similarsimilar environments, or ecological nichesniches

Analogous structuresAnalogous structures are a result of this process Example: penguin limb/whale flipperflipper/fish finfin The wings of insects, birds, pterosaurs, and bats

all serve the same functionsame function and are similar in similar in structurestructure, but each evolved independently independently

Convergent EvolutionConvergent Evolution

Convergent EvolutionConvergent Evolution

ConvergentConvergent Evolution Evolution

Convergent EvolutionConvergent Evolution

ocotillo (left) from the American Southwest, and in the allauidia (right) from Madagascar

Convergent EvolutionConvergent Evolution

Hummingbird Hawkmoth

Convergent EvolutionConvergent Evolution

Similar body shapes and structures

have evolved in the North

American cacti...and in

the euphorbias in Southern

Africa

CoevolutionCoevolution

The mutual mutual evolutionary influenceinfluence between two speciesspecies

When twotwo species evolveevolve in responseresponse to changes in each othereach other

They are closely connected to one another by ecological interactionsecological interactions (have a symbiotic relationship) including:– Predator/prey prey – ParasiteParasite/host – PlantPlant/pollinator

EachEach party exerts selective pressurespressures on the otherother, thereby affecting each others' evolution

CoevolutionCoevolution

CoevolutionCoevolution

A fly and an orchid--can influence each other's evolution

CoevolutionCoevolution

Bumblebees and the flowers the they pollinate have co-evolved so that both have become

dependent on each other for survival.

CoevolutionCoevolution

Coevolution between the yucca moth and the yucca plant. (right) A female yucca moth pushing pollen into the stigma tube of the yucca flower while visiting the flower to deposit her eggs. Yucca moth larvae (left) feeding on seeds in the yucca fruit.

CoevolutionCoevolution

Clown Fish and Sea anemone

CoevolutionCoevolution

Praying Mantis simulates plant to protect itself from predators and eats pests that are attracted to and feed on the plant, so it protects the plant.

CoevolutionCoevolution

Shrimp cleaningTitan triggerfish in Pacific Ocean

GradualismGradualism

The evolution of new species by gradual accumulation of small genetic changessmall genetic changes over long periodslong periods of time

Emphasizing slowslow and steady changesteady change in an organism

Occurs at a slow but constant rateconstant rate Over a short period of time it is hard to hard to

noticenotice

GradualismGradualism

GradualismGradualism Current living zebras (top), extinct quaggas (bottom)

GradualismGradualism

GradualismGradualism

Punctuated EquilibriumPunctuated Equilibrium

Stable periodsStable periods of no change (genetic equilibrium) interruptedinterrupted by rapid changesrapid changes involving many different lines of descent

Opposite of gradualismgradualism It is rare, rapid events of branching branching

speciationspeciation Characterized by long periods of virtual virtual

standstillstandstill ("equilibrium"), "punctuated""punctuated" by episodes of very fast developmentfast development of new forms

Punctuated EquilibriumPunctuated Equilibrium

Horseshoe crabs have change little since their first appearance in the fossil record.

They are in a state of equilibrium

Punctuated EquilibriumPunctuated Equilibrium

Punctuated EquilibriumPunctuated Equilibrium

Gradualism orGradualism orPunctuated EquilibriumPunctuated Equilibrium

Patterns of MacroevolutionPatterns of Macroevolution

that are

can undergo can undergo can undergo can undergo can undergo

in underunderform inin

Species

Unrelated Related

Inter-relationships

Similar environments

Intense environmental

pressure

Smallpopulations

Different environments

Coevolution Convergent evolution Extinction

Punctuated equilibrium

Adaptive radiation

Flow ChartFlow Chart