Chpt. 24 Evolution Processes And Patterns

Front 1

Lamarck

Back 1

-individuals change as they develop in response to challenges posed by the environment
-giraffe necks

Front 2

Darwin and Wallace

Back 2

-the process responsible for change through time is based on variation among individuals in a population

Front 3

transition form

Back 3

a fossil species w/traits that are intermediate btwn those of older and younger species

Front 4

vestigial trait

Back 4

any rudimentary structure of unknown or minimal function that is homologous to functioning structures in other species
i.e. hip bones in whales, embryonic gill pouches in chicks, fish and humans

Front 5

Evidence for Evolution

Back 5

Prediction 1: Species Are Not Static, but Change through Time
-most species have gone extinct
-fossil species often resemble living species found in the same area
-transitional forms document change in traits through time
-earth is ancient
-vestigial traits are common
-populations and species can be observed changing today
Prediction 2: Species Are Related, Not Independent
-closely related species often live in the same geographical area
-homologous traits are common and exist at three levels:
1.genetic
2.developmental
3.structural

Front 6

homology

Back 6

-similarity exists in species descended from a common ancestor
-three different levels:
1)genetic-similar DNA sequences of diff species i.e. 64 common mRNA codons
2)developmental - similarity in embryonic traits i.e. gill pouches in fish,chicks, and humans
3)structural - similarities in adult morphologies i.e. common structural plan in limbs of vertebrates

Front 7

Darwin's Postulates of Natural Selection

Back 7

1)the individuals that make up a population vary in the traits they possess
2)some of the trait differences are heritable
3)More offspring are produced in each generation than can survive. Thus only some survive long enough to reproduce, and of those individuals some will reproduce more than others
4)individuals with certain heritable traits are more likely to survive and reproduce. Natural selection occurs when individuals w/certain characteristics produce more offspring than do individuals w/out those characteristics

Front 8

evolution

Back 8

a change in genetic characteristics (allele frequencies) of a population over time

Front 9

Condensing Darwin's postulates

Back 9

1)heritable variation leads to
2)differential success in survival and reproduction

Front 10

Darwinian fitness

Back 10

-the ability of an individual to survive and produce offspring relative to other individuals in the population
-measured by the amount of offspring left

Front 11

adaption

Back 11

a heritable trait that increases the fitness of an individual in a particular environment relative to individuals lack the trait

Front 12

natural selection and populations

Back 12

natural selection acts on individuals because they experience differential success. But only populations evolve. Allele frequencies change in populations, not in individuals