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67 Cards in this Set

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Conservative Characters

retained with little or no change over long periods

Mosaic Evolution

evolution of different characters at different rates within a lineage

Gradualism

changes accumulate slowly

Saltation

large changes occur suddenly

Example- gradation in bills of sandpipers

gradualism- gradations in curvature and length- bills evolved through small changes

Example- parts of the two different sea urchin species have diff. sorts of changes

mosaic evolution- adult features evolved slowly, larval stages rapidly

T/F Ontogeny recapitulates phylogeny

False- example of vertebrate embryos become less alike as they develop

Modules

units with distinct (uniform) genetic specifications and features (many leaves, teeth, etc)

Individualization

modules that take on their own specific traits (molars vs. incisors) (leaves vs. flower petals)

Example- teeth of mammals

Individualization

Heterochrony

Evolutionary change in the timing or rate of developmental events (Paedomorphosis & Paramorphosis)

Paedomorphosis

adult takes on juvenile form (salamander)

Paramorphosis

adult form is extended (human brain)

Allometry

differential rate of growth of different parts or dimensions of an organism during its ontogeny (bat wing bones- fingers) (elephant tusks- incisors)

Heterotropy

change in the position at which a phenotypic character develops (roots from stems in climbing lianas) (photosynthetic roots)

Evolutionary trends

patterns produced from repeated directional change of a character within an evolutionary lineage or in separate lineages (columbine spur length gets longer due to pollinator coevolution)

Trend: Radiation

divergent evolution of numerous related lineages within a relatively short time (adaptive if the characters support specialization in lifestyles) (not directional)

Example: beak size in Darwin's finches & lips of African cichlid fishes

adaptive radiation- food sources

Genome size

expect a larger genome (# of base pairs BP) in complex organisms


(eukaryotes -> prokaryote -> virus) (NOT true within eukaryotes)

Gene duplication

ancestral gene is copied and pasted back into the genome


results in two loci in descendants that evolve separately

Homology- Paralogous

two copies in one lineage

Orthologous

either copy across lineages

Human Globin Gene Family

gene duplication can lead to specialization of units

Paralogous or Paralogous Regions

gene duplication- large chunks may be duplicated with many genes at the chromosomal level

Polyploidy duplication

non-disjunction in meiosis may produce additional complete sets of chromosomes (duplicated genes are paralogs)


independently evolved genomes are conflated in hybrids (brings orthologs together)

Fossil

any evidence of an organism from more than 10,000 years ago (can still be alive)

Fossil record

direct evidence of evolution (biological diversity, phenotypic transformations, time scale)

Igneous rock

produced by cooling magma

Sedimentary rock

deposited gradually in place

metamorphic rock

other type molded by great heat and pressure

Lithosphere

crust (8 plates total)

Athenosphere

plastic layer beneath lithosphere (origin at oceanic ridges moves plate 5-10 cm/year)

Geologic time- Big Bang, oldest rocks, first life, first animals

14 BYA; 3.8 BYA; 3.5 BYA; 800 MYA

Radiometric dating

ABSOLUTE- must be igneous if rock; atoms in the parent material undergo radioactive decay; half-lives are constant and known; ratio of parent/daughter atoms gives # of half-lives

Carbon-14

up to 40,000 YA

Potassium-40 (potassium-argon)

300,000 years and older



Stratigraphy

RELATIVE- law of superposition; deposition is periodic; strata have chemical and physical signatures that can be matched in different regions; erosion and metamorphism disrupt patterns

T/F- Evolutionary changes within a single species are an example of cladogenesis

False (anagenesis)

Examples- plankton with CaCO3 shells; stickleback fish

gradualism in anagenesis

Changes in mean values of characters in fossil stickleback fish

mosaic evolution

Origins of major groups- Tetrapods

descended from lobe finned fishes

Origins of major groups- birds are therapod dinosaurs

recent feathered fossil discoveries blur distinction; related to T-rex; Archaeopteryx (first feathered dino fossil)

Skeletal features of dinosaurs and birds

toothed beak (reptilian); wing claw (reptilian); airfoil wing with contour feathers (avian); long tail with many vertebrae (reptilian)

Origin of Mammals

Evolution of mammals from amniote stem lineage gradually (130 MY) (Devonian to Jurassic)

T/F- Evolution of mammalian characteristics followed a mosaic pattern

True

Origin of Cetaceans

originate from terrestrial mammals


-Eocene (55-34 MYA)


-closest extant relative is the Hippo


-highly modified for aquatic life

T/F- vestigial structures are structures that are evolutionary remnants and that serve no purpose for the organism

True

Hominins

humans: sister lineage to chimps


diverged from chimp lineage 5-6 MYA Africa

T/F- all hominins were humans in biological terms

True

Hominids

larger group with all great apes

Origin of humans

diverse taxa 4-2 MYA


-tool use in robust Australopithecus spp. 2.3-2.6 MYA

First evidence of Homo spp. (genus)

1.9-1.5 MYA

"missing link"

Australopithecus habilis


-early forms with A. africanis features, later like H. erectus


-Homo spp. probably an unbranched lineage

Homo erectus

1.6mya-200kya


-modern human features in skull, anatomy, behavior by mid-pleistocene (800kya)


-1000cc brain capacity increasing with time


-Africa --> Asia


-sophisticated stone tools, fire utilization widespread (500 kya)

Homo neanderthalensis

-considered distinct from 400-300kya


-transitional but considered separate species (DNA)


-peak cranial capacity 1500cc (larger than ours)


-thick brow, thick dense bones, fully upright position


-advanced tools, ritualized burial likely

Homo sapiens

-appears in africa ~170kya


-co-occurs with neanderthals in the middle east extensively until 40kya


-12kya or earlier spread across Bering into NA

general trends of homo sapiens

Mosaic- apelike ancestor


-increase in brain size


-adaptive nature of changes speculative


-bipedialism posture for carrying food home



punctuated equilibrium

long periods of stasis with rapid shifts from one such "equilibrium" state to another as species form

phyletic gradualism

gradual change not necessarily associated with speciation

Three models of evolution

punctuated gradualism

=punctuated anagenesis- long periods of stasis with rapid shifts from one such "equilibrium" state to another NOT as species form

Single land mass in the earliest Triassic

Pangea

Eurasia and North America were fairly separate by the late _________.

Jurassic

____________ had become fragmented into most of the major southern land masses by the late Cretaceous

Gondwana

By the late ________, the land masses were close to their present configurations

Oligocene

Bering land bridge

2 MYA

Glacial refugia

glaciation "ice age"


peak 22kya, recede 8kya