Patterns of Evolution Honors Biology- Mr. Wilmot

Patterns of EvolutionHonors Biology- Mr. Wilmot

MACROEVOLUTION/MICROEVOLUTION

●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.


●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


●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 has never been observed in any breeding experiment. ●


PATTERNS OF MACROEVOLUTION

A. Mass Extinctions

B. Adaptive RadiationC. Convergent EvolutionD. Coevolution

E. GradualismF. Punctuated Equilibrium

These are models of evolution:

MASS EXTINCTIONS●Event 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

MASS EXTINCTIONS

●Possible causes●Asteroids hitting earth●Volcanic eruptions●Continental drift●Sea levels changing

ADAPTIVE RADIATION (DIVERGENT EVOLUTION)●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.

ADAPTIVE RADIATION

ADAPTIVE RADIATION

ADAPTIVE RADIATION

Diversity in anoles is most strikingin the Caribbean islands

ADAPTIVE RADIATION

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

CONVERGENT EVOLUTION

●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





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


Hummingbird Hawkmoth


Similar body shapes and

structures have evolved in the

North American

cacti...and in the euphorbias

in Southern Africa

COEVOLUTION●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

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 cleaningTitan triggerfish in Pacific Ocean

GRADUALISM

●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

GRADUALISM

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

GRADUALISM

GRADUALISM

PUNCTUATED EQUILIBRIUM●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

PUNCTUATED EQUILIBRIUM

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




GRADUALISM ORPUNCTUATED EQUILIBRIUM

Patterns 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 Chart

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Patterns of Evolution Honors Biology- Mr. Wilmot