Patterns of Evolution Honors Biology- Mr. Wilmot

M ACROEVOLUTION /M ICROEVO LUTION ● Macroevolution- One group of animals evolves into another….due to large scale changes that take place over long periods of time. ● Microevolution- Small scale changes within a species to produce new varieties or species in a relatively short amount of time.

M ACROEVOLUTION /M ICROEVO LUTION ● Both involve changes in allele frequencies in gene pools ● Both work through the same basic processes ● The difference is largely one of approach and scale ● Each offers different insights into the evolution process

M ACROEVOLUTION /M ICROEVO LUTION

● 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. M ACROEVOLUTION /M ICROEVO LUTION

● Macroevolution has never been observed in any breeding experiment. ● M ACROEVOLUTION /M ICROEVO LUTION

P ATTERNS OF M ACROEVOLUTION A. Mass Extinctions B. Adaptive Radiation C. Convergent Evolution D. Coevolution E. Gradualism F.Punctuated Equilibrium These are models of evolution:

M ASS E XTINCTIONS ● E vent in which many types of living things became extinct at the same time. ● Huge numbers of species disappeared. ● Whole ecosystems were wiped out. ● Resulted in burst of evolution of new species in new habitat ● Disrupted energy flow throughout the biosphere and caused food webs to collapse

M ASS E XTINCTIONS ● Possible causes ● Asteroids hitting earth ● Volcanic eruptions ● Continental drift ● Sea levels changing

A DAPTIVE R ADIATION (D IVERGENT E VOLUTION ) ● 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 ● Many new species diversify from a common ancestor. ● The branching out of a population through variation. ● The new species live in different ways than the original species did.

A DAPTIVE R ADIATION

Diversity in anoles is most striking in the Caribbean islands

A DAPTIVE R ADIATION ● Hawaiian honeycreepers ● Variation in color and bill shape is related to their habitat and diet

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

C ONVERGENT E VOLUTION

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

C ONVERGENT E VOLUTION Hummingbird Hawkmoth

C ONVERGENT E VOLUTION Similar body shapes and structures have evolved in the North American cacti...and in the euphorbias in Southern Africa

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

C OEVOLUTION

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

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

C OEVOLUTION 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.

C OEVOLUTION Clown Fish and Sea anemone

C OEVOLUTION 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.

C OEVOLUTION Shrimp cleaning Titan triggerfish in Pacific Ocean

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

G RADUALISM

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

G RADUALISM

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

P UNCTUATED E QUILIBRIUM ● Horseshoe crabs have change little since their first appearance in the fossil record. ● They are in a state of equilibrium

P UNCTUATED E QUILIBRIUM

G RADUALISM OR P UNCTUATED E QUILIBRIUM

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