Origins of Diversity
(how we go about this taxonomy thing)
the process by which new species evolve is called natural selection
Charles Darwin, 1859 On the Origin of Species by Means of Natural Selection
Genetic Variation
random genetic mutations generate variety in all organisms but more so in organisms that usually reproduce asexually
sexual reproduction on the other hand provides genetic variety in every generation (meiosis)
Determining Relatedness
one goal of taxonomy is to determine the evolutionary history of groups of organisms and thus how to classify them
Evidence from Anatomy
looking at comparisons of today’s very different organisms can show us that they may have been related a long time ago
all of the above have the same bones just in different proportions
Evidence from Development
comparisons of early stages of embryonic development can reveal relationships among species that are not obvious from comparisons of adult organisms alone
Evidence from Biochemistry
studying what molecules make up an organism can tell us great information about that organism
ex. Guinea pigs, although they look similar to mice, they are actually made up of different things (chemically speaking)
Evidence from DNA
by looking at genetic information, we can be more precise in our classifications
for many years we felt the other primates must be very different from us since we are so much more advanced but DNA has told up that as much as 98% of our DNA is the same as a chimpanzee’s DNA!
for ancestral genetic lineage, we look at mitochondrial DNA for two reasons
- it mutates at predictable rates
- organisms receive mitochondrial DNA from onlytheir mother
Phylogeny
a hypothesis about the evolutionary history is termed phylogeny
a diagram is used, similar to a family tree, where the oldest relative is at the bottom
forks in each branch represent when an ancestral species split into two new species
a new species that evolved from a common ancestor has derived characteristics
the combination of derived and primitive characteristics help define each level of classification
Cladistics
a classification scheme that is based on phylogeny is called cladistics
a cladogram is a branching tree diagram used to test alternate hypotheses
generally one cladogram is more likely than another
The Value of Phylogeny
the information of how organisms are related distantly is very useful information for such things as: biological control, disease transmission, chemical production, disease resistance (ex. agriculture)
Origins of Diversity
(how we go about this taxonomy thing)
the process by which new species evolve is called natural selection
Charles Darwin, 1859 On the Origin of Species by Means of Natural Selection
Genetic Variation
random genetic mutations generate variety in all organisms but more so in organisms that usually reproduce asexually
sexual reproduction on the other hand provides genetic variety in every generation (meiosis)
Determining Relatedness
one goal of taxonomy is to determine the evolutionary history of groups of organisms and thus how to classify them
Evidence from Anatomy
looking at comparisons of today’s very different organisms can show us that they may have been related a long time ago
all of the above have the same bones just in different proportions
Evidence from Development
comparisons of early stages of embryonic development can reveal relationships among species that are not obvious from comparisons of adult organisms alone
Evidence from Biochemistry
studying what molecules make up an organism can tell us great information about that organism
ex. Guinea pigs, although they look similar to mice, they are actually made up of different things (chemically speaking)
Evidence from DNA
by looking at genetic information, we can be more precise in our classifications
for many years we felt the other primates must be very different from us since we are so much more advanced but DNA has told up that as much as 98% of our DNA is the same as a chimpanzee’s DNA!
for ancestral genetic lineage, we look at mitochondrial DNA for two reasons
- it mutates at predictable rates
- organisms receive mitochondrial DNA from only their mother
Phylogeny
a hypothesis about the evolutionary history is termed phylogeny
a diagram is used, similar to a family tree, where the oldest relative is at the bottom
forks in each branch represent when an ancestral species split into two new species
a new species that evolved from a common ancestor has derived characteristics
the combination of derived and primitive characteristics help define each level of classification
Cladistics
a classification scheme that is based on phylogeny is called cladistics
a cladogram is a branching tree diagram used to test alternate hypotheses
generally one cladogram is more likely than another
The Value of Phylogeny
the information of how organisms are related distantly is very useful information for such things as: biological control, disease transmission, chemical production, disease resistance (ex. agriculture)