Evolution Flashcards
Biological evolution, the observable facts
A. Change in species over time
B. Change in gene frequencies from generation to generation
C. A Process of change
Proposed mechanism for evolution
natural selection
natural selection requires
- Genetic diversity
- differential reproduction by individuals with the most fit genes
- Increase in those genes within population
carolus Linnaeus
Binomial Nomenclature Genus species 2. nested groupings into increasingly specific categories based on morphology K P C O F G S Kingdom, phylum, class, order, family, genus, species
stratification
rock laid down in layers, oldest at bottom
fossils in strata show when organisms lived
order of appearance Older fossils more dissimilar to modern
species appear and disappear
Cuvier
catastrophism
catastrophes destroyed species in an area new species moved in
Lamarck
one of many to propose that life evolves as environments change
first to propose mechanism:
use and disuse
inheritance of acquired characteristics
Pre Darwin people/ ideas
Carolus Linnaeus
stratification
cuvier
Lamarck
Darwins contemporaries
Charles Lyell
Thomas malthus
Alfred Wallace
Charles lyell
Geologist Theory of Uniformity: Natural processes observed today are the same as processes acting in the past at same rate contradicted young earth theory millions of years
Thomas malthus
- war and famine result from human overpopulation
2. Other organisms also produce more individuals than can survive
Alfred Wallace
- first to publish Natural Selection as a mechanism for evolution
- ideas nearly identical to Darwin’s
Charles Darwin
Origin of Species
extensive evidence of natural selection
Origin of species three main ideas
1) Unity of Life: shared characteristics attributed to shared common ancestor
2) Diversity of Life: due to descent with modification
3) Match between organisms and environments: due to adaptation
Artificial selection
selective breeding
can produce visible change over a life-time
Darwins inference over artificial selection
If artificial selection can produce rapid change….then natural selection could produce dramatic change given enough time
Darwins inference over overpopulation (malthus)
survival most likely for those best fit to their environment
Darwins inference over members of a population vary in inherited traits
If only some organisms can survive then those with best traits are more likely to survive
natural selection four parts
overproduction
inherited variation
struggle to survive (best fit)
successful reproduction
morphological evidence example
mammal neck bones and bird neck bone differences
mammal and bird neck bone differences
mammal neck bones 7, giraffe neck vertebrae are each elongated no new bones,
bird neck bones 13-25, birds with short neck have curve in neck vertebrae, not fewer vertebrae
fitness
ability to pass on its genes:
survive, mate, fertile offspring reproduce
adaptation
: inherited traits that improve fitness in a given environment
- individuals can NOT adapt its genetic!!
- only populations adapt over generations
theory of evolution parts
speciation
adaptive radiation
universal common ancestor
speciation
one species branches into 2 new species (ancestral species gone)
adaptive radiation
one species gives rise to many species (common after mass extinctions)
- individuals disperse to new environments
- adapting to new environment causes them to change
universal common ancestor parts
all started from some single celled organisms 1. ‘the unity of life’ 2.universal genetic code DNA, RNA 3. shared genes (homeotic genes) 4. Semiconservative replication 5.transcription /translation (Met) 6. shared proteins(DNA and RNA polymerase)
direct observation with examples
species change over time
ex Bacteria develop antibiotic resistance
weeds develop resistance to roundup
Grants finch research
recorded beak depth of all finches on an island over 30 years
after drought recorded larger beaks
homology
similarities resulting from common ancestor
homologous structures
anatomical features
same underlying structure
may have adapted to different function
Embryo homology
can be lost in adult, ex; pharyngeal arches – all chordates (vertebrates)
post anal tail – all chordates
chordate limbs
same bones just different shape due to different function of appendage
vestigial structures
inherited from ancestor but no longer used
explains presence of useless structures
pelvic girdle & femur in whale & snake
molecular homologies
same DNA/ protein
all organisms homologous DNA structure
Many homologous DNA genes
1. some have developed a new function, some still same function, some vestigial
a. genes for ribosome subunits homologous between humans and bacteria
fossil record
document formation of new species by sequential fossils
biogeography
Geographic distribution of species
endemic species
similar species from different continents not genetically similar
endemic species
ancestor from mainland
adaptive radiation
homologies shared with mainland species
island species all share: homologous structures and proteins/DNA
convergent evolution
Similar species from different continents not genetically similar
