Patterns of Evolution

Macroevolution/Microevolution allele gene  Both involve changes in allele frequencies in gene pools same basic  Both work through the same basic processes differenceapproach scale  The difference is largely one of approach and scale offers insights evolution  Each offers different insights into the evolution process

Macroevolution/Microevolution family large long  Macroevolution- One genus or family evolves into another….due to large scale changes that take place over long periods of time. Small species short  Microevolution- Small scale changes within a species to produce new varieties or species in a relatively short amount of time.

Macroevolution/Microevolution Macroevolution Large-scale 1. Large-scale changes in gene frequencies longer time period 2. Occurs over a longer (geological) time period level of species separated 3. Occurs at or above the level of species in separated gene pools extended 4. Consists of extended microevolution microevolution Microevolution Small-scale 1. Small-scale changes in gene frequencies few generations 2. Occurs over a few generations within a species same 3. Occurs within a species or population in same gene pool smaller 4. Refers to smaller evolutionary evolutionary changes

Macroevolution/Microevolution Macroevolution not 5. Has not been observed directly observed 6. Evidence based on remnants past remnants of the past More 7. More controversial 8. Example: Birds from reptiles Microevolution Observable 5. Observable 6. Evidence produced experimentation by experimentation Less 7. Less controversial 8. Example: Bacterial resistance to antibiotics

Macroevolution/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/Microevolution

Patterns 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 Extinctions many at the same time  Event in which many types of living things became extinct at the same time. species disappeared  Period in which huge numbers of species disappeared. ecosystemswiped out  Whole ecosystems were wiped out habitatsopen  Left habitats/niches open burst of evolution  Resulted in burst of evolution of new species in new habitat energy flow food webs collapse  Disrupted energy flow throughout the biosphere and caused food webs to collapse

Mass Extinctions  Possible causes – Asteroids – Asteroids hitting earth – Volcanic – Volcanic eruptions drift – Continental drift – Sea levels – Sea levels changing

Mass Extinctions  Is an on-going process

Adaptive Radiation ancestral species adapted many diverse different habitat  The evolution of an ancestral species, which was adapted to a particular way of life, into many diverse species, each adapted to a different habitat species common ancestor  Many new species diversify from a common ancestor. branching out variation  The branching out of a population through variation. livedifferent thanoriginal  The new species live in different ways than the original species did.

Adaptive Radiation

Diversity in anoles is most striking in the Caribbean islands

Adaptive Radiation  Hawaiian honeycreepers  Variation in color and bill shape is related to their habitat and diet

Convergent Evolution  Oppositedivergent evolution  Opposite of divergent evolution (adaptive radiation)  Unrelatedorganismsevolve similaritiessimilar niches  Unrelated organisms independently evolve similarities when adapting to similar environments, or ecological niches  Analogous structures  Analogous structures are a result of this process flipperfin  Example: penguin limb/whale flipper/fish fin same functionsimilar in structure independently  The wings of insects, birds, pterosaurs, and bats all serve the same function and are similar in structure, but each evolved independently

Convergent Evolution

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

Convergent Evolution Hummingbird Hawkmoth

Convergent Evolution Similar body shapes and structures have evolved in the North American cacti...and in the euphorbias in Southern Africa

Coevolution mutual influence species  The mutual evolutionary influence between two species twoevolveresponse each other  When two species evolve in response to changes in each other ecological interactions  They are closely connected to one another by ecological interactions (have a symbiotic relationship) including: prey – Predator/prey – Parasite – Parasite/host – Plant – Plant/pollinator  Eachpressures other  Each party exerts selective pressures on the other, thereby affecting each others' evolution

Coevolution

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

Coevolution Bumblebees and the flowers the they pollinate have co-evolved so that both have become dependent on each other for survival.

Coevolution 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.

Coevolution Clown Fish and Sea anemone

Coevolution 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.

Coevolution Shrimp cleaning Titan triggerfish in Pacific Ocean

Gradualism small genetic changes long periods  The evolution of new species by gradual accumulation of small genetic changes over long periods of time slowsteady change  Emphasizing slow and steady change in an organism constant rate  Occurs at a slow but constant rate hard to notice  Over a short period of time it is hard to notice

Gradualism

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

Gradualism

Gradualism

Punctuated Equilibrium  Stable periods interruptedrapid changes  Stable periods of no change (genetic equilibrium) interrupted by rapid changes involving many different lines of descent gradualism  Opposite of gradualism branching speciation  It is rare, rapid events of branching speciation virtual standstill"punctuated" fast development  Characterized by long periods of virtual standstill ("equilibrium"), "punctuated" by episodes of very fast development of new forms

Punctuated Equilibrium  Horseshoe crabs have change little since their first appearance in the fossil record.  They are in a state of equilibrium

Punctuated Equilibrium

Gradualism or Punctuated Equilibrium

Patterns of Macroevolution that are can undergo inunder formin Species UnrelatedRelated Inter- relationships Similar environments Intense environmental pressure Small populations Different environments Coevolution Convergent evolution Extinction Punctuated equilibrium Adaptive radiation Flow Chart