Lecture 1 Flashcards
Two core Tenets of evolution
- Living things change over time
- adaptations have arisen through natural selection
what does evolution challenge?
the view of special creation
define special creation
the direct creation of all living things in effectively their present form
state 5 important conclusions about evolution verified by scientific study
- organisms on earth have changed through time
- changes are gradual, not instantaneous
- lineages split by speciation, resulting in the generation of biodiversity
- all species have a singular common ancestor
- adaptations result from natural selection
evidence for organisms changing through time
fossil records
why are changes in traits in organisms gradual and not instantaneous?
processes of evolution take different amounts of time, but always have to work with pre-existing variation, limiting the rate of change.
biodiversity and adaptation are the
products of evolution
describe speciation
process by which one species bifurcates into two which do not go back together. iterative rounds of speciation give exponential growth of this process.
give 2 definitions of biodiversity
- the diversity of life on earth
- the number and kinds of living organisms in a given area
give 2 definitions of adaption
- any trait that makes an organism better able to survive or reproduce in a given environment (noun)
- the evolutionary process that leads to the origin and maintenance of such traits, reproducing and surviving better in an environment (verb)
major areas of evolutionary study
- evolutionary history (i.e. patterns); reconstructing how life on earth happened
- evolutionary mechanisms (i.e. processes); what gave rise to the life that we see
microevolution
evolutionary patterns and processes observed within species
macroevolution
evolutionary patterns and processes observed among species
draw a diagram for macro and microevolution, as well as evolutionary history and mechanisms
goals of evolutionary history
identify and understand long term patterns in evolution, including common ancestry
evolutionary history in practice
uses comparative data from sub-disciplines of systematics, biogeography, palaeontology, morphology, development and molecular biology
give 2 alternative terms for an evolutionary tree
a phylogenetic tree = a phylogeny
what is the purpose for evolutionary trees?
to reflect ancestor-descendant links
name of split points in evolutionary trees
nodes
can trees with different sets of species represent the same common ancestors?
yes - this also depends on rotation of branches on the tree
goals of evolutionary mechanisms
- determine the particular processes responsible for evolutionary change
evolutionary mechanisms in practice
- uses experimental and comparative studies of the genetics and ecology of populations
- focuses primarily on the population level
state and describe the 4 approaches that are used to address scientific questions
- observational - describe and quantify
- theoretical - develop models (verbal, graphical, mathematical, computational)
- comparative - obtain same data from many species
- experimental - manipulate a system to address a specific hypothesis; requires an experimental design and statistical analysis
all good scientific theories have —- and the strongest studies use
testable and falsifiable hypotheses; more than one source of evidence
give 4 reasons as to why evolution is relevant?
- children’s questions/understanding life on earth
- medicine - mitigating effects of pathogens (eg variants of covid-19)
- agriculture
- how can we design strategies to avoid herbicide and insecticide resistant superweeds/super pests?
- what genes were important for crop evolution? - climate change - selection pressures will be applied
public doubts about evolution
- extremely recent scientific concept (165 years is a brief time frame)
- very personal implications: direct ramifications about who we are and where we came from
- violates literal interpretations of religious texts
