unit 7 part 2 (7.6-7.13) Flashcards
geographical evidence of evolution
characteristics of habitat or land area
geological evidence of evolution
environmental features of the earth over time (ex: fossils)
fossils
preserved remains, impressions, and traces of living organisms that document patterns of evolution and changes in the environment
physical evidence of evolution
based on phenotypes
biochemical evidence of evolution
based on the chemical composition of living things (comparison of biomolecules like DNA + proteins), comparison of DNA nucleotide sequences, protein sequences
mathematical evidence of evolution
based on calculations and statistics (models and stimulations)
fossils can be dated by…
age of rocks where fossil is found, rate of decay of isotopes inc carbon-14, geographical data
morphological homologies
represent modified traits shared among different species (homologous and vestigal structures)
homologous structure
variation in a structure that was present in a common ancestor
vestigial structure
reduced or obsolete features that serve little or no purpose for organism (remnants of ancestral feature)
analogous structure
evolved independently in different species due to similar environmental conditions and selective pressures
common molecular features across species
DNA+RNA are carriers of DNA and have universal processes
Major part of genetic code is shared
metabolic pathways (glycolysis)
genetic info in euk
multiple linear chromosomes, tightly coiled DNA with histones, capped with telomeres, found in nucleus, large genome
mechanisms of genetic change
changes in DNA (mutations), cell division (sexual reproduction, independent assortment, crossing over), environmental disruptions (sudden changes, allele frq changes)
strata layers
arrange fossils in order they were deposited
bacteria species evolution
antibiotic resistance
pathogens
infectious agent that can produce a disease and evolve to cause emergent genomes (have high mutation rates and inc diversity)
scientific theory
explanation backed up by scientific evidence
scientific law
describes a natural phenomenon
geological evidence
fossil record, biogeograpy, transitional forms
morphological evidence
homologous structures, vestigal structures, embryological
biochemical evidence
conserved genes, conserved molecules, conserved processes
allen’s rule
warm blooded animal evolve to have smaller heat-losing appendages in cold conditions
species
group capable of inbreeding and exchanging genetic information to produce viable, fertile offspring
speciation
creation of new species, results in diversity of life forms
reproductive isolation
biological barriers that keep members of two species from interbreeding and producing fertile offspring
prezygotic barriers
prevent production of fertilized egg
habitat isolation, temporal isolation, behavioral isolation, mechanical isolation,gamete isolation
habitat isolation
species occupy different habitats and rarely come into contact
temporal isolation
species breed in different times of day, seasons, or years
behavioral isolation
species have different courtship behaviors or mating preferences
mechanical isolation
reproductive structural differences prevent successful mating/reproduction
gamete isolation
sperm of one species may not be able to fertilize the eggs of another species
postzygotic barrier
prevent zygote from developing into viable, fertile offspring
hybrid inviability
mating results in zygote, but incompatibility may stop development of zygote
hybrid sterility
hybrid offspring is produced but sterile (ex: mule)
hybrid breakdown
1st gen are viable and fertile but resulting generations are feeble and sterile
allosteric specieation
evolution of a new species due to geographic isolation for a long period of time (separations exposes populations to different selective pressures)
sympatric speciation
evolution of a new species due to individuals being reproductively isolation from surviving ancestral population (no geo barrier, result in mutations (polyploidy)) can result in habitat differentiation and sexual selection
punctuated equilibrium
evolution occurs rapidly after a long period of stasis, changes in ecological conditions are the stimulus for evolution
gradualism
evolution gradually occurs over many (100s-1000s) years. ecological conditions change over a long period of time
divergent evolution
adaptation to new habitats results in phenotypic diversification. speciation can be rapid during times of adaptive radiation as new habitats become available
speciation, common ancestry, homologous structure, descent with modification
adaptive radiation
evolution of new species that allows empty ecological roles (niches) to be filled
microevolution
changes in allele frequency over time in a population
macroevolution
broad pattern of evolution above species level
phylogenic tree / cladogram
branched diagram that shows evolutionary relationships amongst species (can be by fossils or molecule clock)
what is shown in phylogenic trees + cladograms
SPECIATION, shared characteristics in lineage, derived characteristics, traits that are gained/lost, common ancestory
outgroup
represents lineage of least closely related organism, used as reference of comaprison that shows how main group fits into evolutionary tree of life
node
where two lines meet, common ancestor
root
represents common ancestor of all species on the tree
info used for phylogenic trees and cladograms
morphological similarities from living or fossil species OR DNA/protein sequence similarities (more accurate and reliable)
derived characteristic
evolutionary novelty unique to a group of organisms with a shared ancestor (clade)
NOT present in outgroup
difference between phylogenic tree and cladogram`
phylogenic tree- shows relationships and time through the length of branches, shows convergent evolution
cladogram- relationship but NOT time
convergent evolution
two organisms arise with similar adaption but don’t have common ancestry. analogous structures (same in diff species because of similar selective pressures)
maximized parsimony
which ever explanation required the least amount of random mutations is probably correct
shared ancestral character
characteristic that originates in an ancestor, not unique to the clade
molecular clock
measuring time of evolutionary change based on observation of other genomes in the region
mutations happen at a
semi-regular rate, so we can calculate how long ago a species diverged
extinction
disappearance of a species, such that no future genarations will naturally populate the earth
- part of the history of life, ongoing and can occur on small and large scale. a marker of geological time
possible causes of extinction
times of ecological stress, catostrophic events, decreases in species diversity, human activity
high biodiversity =
high speciation and low extinction… and vice versa
niches
role of an organism plays within its environment (ex: producer, decomposer, etc)
extinction opens up niches, this can lead to speciation and adaptive radiation
genetically diverse populations are…
more resilient to environmental change
adaptation variety inc chances a species can withstand pressures
example of population resilience
antibiotic resitance
origin of life geological evidence
age of the earth (4.6 bya), environment was too hostile for life until 3.9 bya, earliest fossil (3.5 bya)
models about origin of life on earth
primitive earth provided inorganic precursors from which organic molecules could have synthesized
presence of free energy and absence of significant quality of atmospheric O2
organic molecules possible transported by celestial event
what was probably the first genetic molecule
RNA
experiments show about the prehistoric earth’s enviroment shows the
abiotic synthesis of macromolecules
homology
similarity from common ancestory
how old is the earth
4.6 bya
when was the first traces of life
3.5 bya
transitional forms
morphological structures that can be traced back to a common ancestor. overtime this form adapts to suit the species’ environment
biogeography
where the fossils are found and what the environment is like in those places
steps of the first cells
1) synthesize organic molecules
2) monomers join to form macromolecules
3) protocells (self assembly)
4) RNA world hypothesis for genome and protein replication (ribozymes!)
domain bacteria and archae
single celled prokaryotes
three domain system
domain euk, domain arch, domain bacteria
