evolution Flashcards
(24 cards)
what is genetic drift
the change in frequency of an existing gene variant in the population due to random chance. genetic drift may cause gene variants to completely disappear and therefore reduce genetic variation
what is gene flow
the transfer of genetic material from one population to another
what is natural selection
the process of which living organisms adapt and change to better suit their environment.
those who are more adapted to their environment are more likely to survive and reproduce than those who are not adapted.
what is mutation
a change that occurs in a DNA sequence, either due to mistakes when the DNA is copied or as a result of environmental factors
what is selection pressure
selection pressures determine which individuals will do the best at surviving and reproducing in their environment.
some individuals produce more offspring than their environment can handle due to lack of food or disease
what is population
any group that shares one or more characteristic
types of evidence for evolution
fossils, DNA and protein structure, biogeography and embryology
reasons for a variation in a population
major causes include mutations, gene flow and reproduction
why we need a variation in a population
it allows some individuals within a population to change and adapt to their changing environment
what is homologous structures
physical features shared due to having a common ancestor
what is a analogous structure
features of different species that are similar in function but not necessarily in structure
do not attain from a common ancestral feature
How homologous and analogous structures relate to types of evolution
homologous structures provide evidence for common ancestry
analogous structures show that similar selective pressures can produce similar adaptations
what is a pentadactyl limb
consisting of an upper arm or thigh, a forearm or shank, and a hand or foot bearing five digits.
what are vestigial structures
a feature that a species inherited from an ancestor but that is now less elaborate and functional than in the ancestor.
DNA base conversions
T –> A
C –> G
G –> C
A –> U
molecules involved in studying DNA
Adenine
Cytosine
Guanine
Thymine
what is biogeography
the study of the geographic distribution of plants, animals, and other forms of life.
what is embryology
the study of embryos and their development.
what are the two main categories of fossils
body fossils and trace fossils
what is a body fossil
parts of the organism, such as bones or teeth
what is a trace fossil
a footprint, trail, burrow, or other trace of an animal rather than of the animal itself
what is a index fossil
Index fossils are used to define geological periods
what is absolute dating
it is used to determine the actual age of a fossil
what is relative dating
it compares the age of a fossil with the rock around it
