Chapter 2: Evidence for Evolution

Vestigial features

Vestigial features

________ are of great importance, which may reflect inheritance.

Dolphins

________ have many OR genes, but all are pseudo (they dont need to smell their underwater)

Macroevolution

________: large- scale evolutionary changes, evolution on a species level (speciation and extinction), and at a higher taxonomic classification (appearance or disappearance of genera, families, orders, etc)

Rudimentary organs

________ can often be detected in the embryo, but are lost later during development.

Pseudogene

________- a sequence of DNA similar to a functional gene but nonfunctional, probably the remnant of a once functional gene that accumulated mutations.

Mechanism

________ 2: Natural selection (an organ useful in some conditions might be injurious in others (beetles on islands))

Extinction

________ is the complete elimination of all individuals in a species from the earth.

Phylogenetic tree

________: a graphic representation of relatedness between species, genera, etc.

Microevolution

________: Small scale evolutionary changes occur in gene frequency and trait distributions that occur in populations and species.

archeopteryx

The ________ had modern feathers but a dinosaur- like skeleton.

Evolution

________- descent with modification or changes in the genetic population over time (across generations)

Law of succession

________: Fossil types are succeeded in the same geographical area by a similar fossil and or extant species.

Sister Taxa

________: two taxa share a more recent common ancestor with each other than either does with any other species on the tree.

Olfactory receptor

________ (OR) genes: humans have over 1000 (70 % pseudo) sense of smell correlates with loss of genes, mice have over 1500 (20 %) and a more accurate sense of smell, dogs have more than 800 (pseudo 18 %) and olfactory sensitivity is 100x that of humans.

fossil

A(n) ________ is any trace of an organism that lived in the past.

Transitional Forms

________- Ancestor → transitional form → descendant.

Molecular homology

________ has two forms, the conservation of the genetic code as well as the case of shared genetic flaw.

Vestigial Structure

________- a functionless or rudimentary version of a body part that has an important function in a closely related species; structure with no apparent nor predictable function (unusable organs)

Fossils of dinosaurs

________ also have bristly structures, filamentous structures, and modern feathers.

Evolution

descent with modification or changes in the genetic population over time (across generations)

Evidence for evolution

evidence of change over time and evidence of common ancestry

Microevolution

Small scale evolutionary changes occur in gene frequency and trait distributions that occur in populations and species

Macroevolution

large-scale evolutionary changes, evolution on a species level (speciation and extinction), and at a higher taxonomic classification (appearance or disappearance of genera, families, orders, etc)

Vestigial Structure

a functionless or rudimentary version of a body part that has an important function in a closely related species; structure with no apparent nor predictable function (unusable organs)

Mechanism 1

disuse

Mechanism 2

Natural selection (an organ useful in some conditions might be injurious in others (beetles on islands))

Pseudogene

a sequence of DNA similar to a functional gene but nonfunctional, probably the remnant of a once functional gene that accumulated mutations

Olfactory receptor (OR) genes

humans have over 1000 (70% pseudo) sense of smell correlates with loss of genes, mice have over 1500 (20%) and a more accurate sense of smell, dogs have more than 800 (pseudo 18%) and olfactory sensitivity is 100x that of humans

Change through time evidence

soapberry bug ate the fruit of host plants, prior to 1925 it was the Southern Florida balloon vine which has thick fruit, since 1926 it has been the central Florida flat-podded golden rain tree which has thin fruit

Evidence of Macroevolution

evidence of fossil record (fact of extinction), transitional forms, and the law of succession

Example

Irish Elk (neither Irish nor elk nor moose nor reindeer) is an extinct species a relative to a living species, evolved during glacial periods, unable to adapt to subarctic conditions of the last glaciations, the last one died -11,000 years ago

Law of succession

Fossil types are succeeded in the same geographical area by a similar fossil and or extant species

Example

similarity in marsupials fossils in Australia and the marsupials currently living there

Transitional Forms

Ancestor → transitional form → descendant

Examples

reptile → archeopteryx → bird

Phylogenetic tree

a graphic representation of relatedness between species, genera, etc

Taxon

any named group of organisms such as species or genus

Sister Taxa

two taxa share a more recent common ancestor with each other than either does with any other species on the tree

Homology

the study of likeness, structural similarity between species despite the difference in function, the similarity between species the results from inheritance of traits from a common ancestor

Evolution

descent with modification

Microevolution

small scale evolutionary changes, changes that occur in gene frequency and trait distributions that occur in populations and species

Macroevolution

large scale evolutionary changes, evolution on a species level (speciation and extinction) and at a higher taxonomic classifications, typically refers to the evolutionary differences among population usually in morphology

vestigial structures

a functionless or rudimentary version of a body part that has an important function in other closely related species; a structure with no apparent nor predictable function

Eye sockets on a blind cave fish

example of vestigial structure

Pseudogene

a segment of DNA similar to a functional gene but nonfunctional, probably the remnant of a once functional gene that accumulated mutations

A dolphin's olfactory receptor genes

example of a pseudogene

evidence for macroevolution

fossil record, transitional forms, law of succession

Law of Succession

fossil types are succeeded, in the same geographic area, by similar fossils or living species

Archeopteryx

Famous bird-like fossil that links birds and reptiles (transitional form)

phylogenetic tree (cladogram)

graphic representation of relatedness between species, genera, etc

Taxon

any named group of organisms (species, genus)

Sister Taxa

two taxa share a more recent common ancestor with each other than either does with any other species on the tree

Homology

study of likeness, similarity between species that results from inheritance of trait from a common ancestor

structural homology

forelimbs of vertebrates(different function but the same sequence of bones)

developmental homology

A similarity in embryonic form, or in the fate of embryonic tissues, that is due to inheritance from a common ancestor.

molecular homology

conservation of genetic code or a shared flaw

Evidence for evolution

vestigial structures, pseudogenes, law of succession, transitional forms, homology

Analogy

similarity due to a common function, NOT ancestry

Example of change over time

soapberry beak size changed in response to the new food