Bio 1 Unit 2: evolution

descent with modification (evolution)

a change in the genetic composition of a population from generation to generation.

Scala naturae

the scale of increasing complexity on which life forms could be arranged.

Fossil

the remains or traces of organisms from the past

Strata

layers of sedimentary rock that form from sand and mud settling in aquatic habitats

Paleontology

the study of fossils

adaptations

organisms inherited characteristics that help their survival and reproduction in certain environments

Natural selection

individuals that have inherited traits that give them an advantage to survive and reproduce at higher rates than others

unity of life

characteristics of organisms that are the same

Diversity of life

differences in organisms

artificial Selection

Selective breeding of plants and animals

Homology

Similarity resulting from common ancestry

homologous structures

closely related species share similar features

vestigial structures

remnant features that served a purpose in the past but have no importance now

Pseudogenes

Genes that have lost their functions

Molecular homology

shared genes inherited from a very distant common ancestor

Divergent evolution

when one common ancestor splits into different species that grow dissimilar over time.

convergent evolution

the independent evolution of similar features in different lineages

Analogous structures

features that share similar functions but not common ancestry

Fossil record

Documentation of the pattern evolution

Biogeography

the study of the geographic distribution of species

endemic

constantly present or native to a certain area

adaptive evolution

the match between a species and their environment improves

relative fitness

the contribution an individual makes to the gene pool of the next generation relative to the contributions of other individuals

sexual dimorphism

a difference in sexual characteristics between males and females of the same species

Intrasexual selection

selection within the same sex

Intersexual selection

individuals of one sex select their mates from the other sex

list the groups in the classification system developed by Linnaeus

(largest to smallest) Domain, Kingdom, Phylum, Class, Order, Family, Genus and Species.

How did Darwin suggest organisms should be classified?

based on evolutionary relationships

in the fossil record why do some species appear and others disappear?

because new species form from evolution and some species go extinct

younger fossils are in ____ strata and older fossils are in ____ strata

higher, lower

How did hypotheses in geology help form Darwin’s hypotheses on evolution?

provided vast time change and slow cumulative change required for biological evolution to be plausible

James Hutton

found geological features could be explained by gradual mechanisms, ex. a valley is formed by rivers

Charles Lyell

found the same geological processes from the past are still operating today at the same rate

Jean-Baptiste de Lamark’s hypothesis

found life evolves as environments change. ex. giraffes making their necks longer to eat leaves an passing down that trait

Why is Lamark’s hypothesis incorrect?

because changes to the body’s cell during one’s lifetime does not change the genetic code in the reproductive cells.

What is Darwins observation of geographic proximity?

organisms in temperate regions of South America more closely resemble species in South American tropics than species living in temperate regions of Europe.

What evidence supports Darwins observations of geographic proximity?

fossils were different from living species but were still clearly South American

what are two observations Darwin made that led to his hypothesis of natural selection?

a type of bird (finches) were unique to one or two adjacent islands, and animals of the island resembled species on the south American mainland

what inferences did Darwin come to based on his observation?

the islands were colonized by organisms from South America and then diversified

what are 4 different types of data we collect in our study of evolution?

direct observations of evolution, homology, the fossil record, and the biogeography

why do humans artificially force evolution to occur?

to shape plants and animals to fit human needs, desires and survival goals

what are examples of homologous structures in mature organisms and during embryonic development

mature organisms: human, cat and whale embryonic development: pharyngeal pouches

what are examples of vestigial structures in humans?

appendix, wisdom teeth and tail bone

why might two unrelated organisms evolve to have similar characteristics (analogous structures)?

they’ve adapted to similar environments in similar ways

how do transitional fossils show the evolution of whales from land-dwelling animals?

it shows the gradual change sin skeleton shape, skull structure, limb reduction and habitat

how does biogeography influence the location of fossils?

knowledge of the continental drift and evolution predict where fossils might be found

what’s the difference between adaptive evolution and chance occurrences?

adaptive evolution is the match between species and their environment improves, while chance is the creation new genetic information ex. mutations in DNA

how can we determine which of the two individuals is relative the most fit?

you compare their individual reproductive success

what is directional selection?

favours individuals exhibiting one extreme of a phenotypic range ex. pine beetles with adaptations to survive in colder temps

what is disruptive selection?

favours individuals at both extremes of a phenotypic range over individuals with intermediate phenotype. ex. black-bellied seed cracker finches

what is stabilizing selection?

acts against both extreme phenotypes and favours intermediate variants ex. birth weight of human babies falls in the range of 3-4kg

what role has sexual selection played in the evolution of sexual dimorphism?

the distinct difference in size, colour, or shape between males and females of the same

what is frequency dependent selection?

the fitness of a phenotype depends on how common it is in the population ex. scale eating fish in Africa.

what is heterozygous advantage?

individuals who are heterozygous have greater fitness than either kind of homozygotes ex. b polypeptide subunit of hemoglobin