Week 3 Flashcards
Darwins theory of natural selection
-All species can (or will) produce far more offspring than can survive
-All species have variations
-Competition for resources means that some of these variations can be advantageous.
-Individuals with the advantageous variation would naturally produce more offspring so these advantageous variations are likely to be passed on
-Over time, the accumulation of advantageous variations within a population could lead to the evolution of a new species
punctuated equilibrium
his theory proposes that major evolutionary developments often occur relatively quickly in geological terms, followed by extended periods of little to no noticeable change.
- Transition from austropithecus to homo habilis
Gradualism model
The theory that evolution is a long slow process
-Homo erectus fossils show evidence of gradualism change
adaptive radiation
Process in which one species occupies a new ecological niche, quickly increasing its population and diversifying into a new species.
Species is able to adapt quickly to one or more ecological niches
Gene flow
movement of genes between populations that are members of the same species but that do not normally mate with one another
Speciation
Formation of new species
-Development of the Congo river created the separation of the common ancestor of chimps and bonobos, that created those two species.
Species- a population of individuals that can
mateand produce fertile offspring in the wild
DONKEY
Dating by Association
If two things are found in the same stratigraphic layer, and the antiquity of one object is already known, then the other object is likely the same age.
radiocarbon dating
Measuring how much carbon 14 is preserved in organic remains.
-Best for sites less than 50k years old
potassium-argon dating
Measuring the rate of change of potassium changing to argon
- Best for sites over 200,000 years old
Specific Skeletal changes that allowed for bipedalism
-Repositioning of foramen magnum at skull base
-Changes to the vertebral column
-Changes to the pelvis (widening, basin shape, weight distribution)
-Lenghtening of femur
-Modifications to the knee
-Angling of the femur inward
-Changes in the foot ( arch, realignment of big toe)