Ch1: Origin of Species Flashcards
What is the Great Chain of Being? Is it effective organisation?
A hierarchy of life forms, it is a ineffective organisation of groups.
What kind of system did Carolus Linnaeus create? What was wrong with this classification?
He classified organisms based on morphological similarities of biological entities.
It did NOT exaplain why there was diversitiy.
What was Jean-Baptiste Lamarck’s theory on evolution?
He believed organisms acquired adaptations throughout their lives.
What did Nicholas Steno realise, and why was it significant?
He realised the importance of fossils, and that they were a source of information for how the world used to look.
How does Mary Anning theory on fossils impact how we understand the existence of organisms?
She discovered fossils that fit with no current living creature, and allowed us to understand extinction
Define evolution
The cumulative change in the genetic composition of a population or species over time
What are Charles Darwin’s 3 propositions, based on the theory of evolution, describe these propositions:
1) Species are not immutable:
- meaning species can and will change over time (phenotypic variation)
2) Descent with modification occurs:
- Divergence of species occurs as different traits are inherited
3) Natural Selection:
- selective pressure acts on organisms and the fittest individual is able to reproduce and outcompete other organisms
Define speciation
An evolutionary consequence based on reproductive ISOLATION.
A divergence of species from a common ancestor.
What is relatedness of species based on? (Hint there are 3 things)
1) Morphological traits
2) Fossil Records
3) Genetic Composition
Define selective breeding
The purposeful breeding of organisms to produce and mix desired traits.
It may lead to the creation of new species (evolution).
What is the difference between microevolution and macroevolution?
Microevolution relates to evolutionary changes that occur within a single population. Its scope is fairly small, since it only deals with one species at a time.
Macroevolution relates to larger-scale changes and interactions between multiple populations (and thus multiple species). Ex~ extinctions, diversification, origins.
Define phylogenetic tree, and what an out-group is.
A depiction of the relationship between species.
An out-group is a species included in a group of species that shares NONE of the morphological traits of interest. Although they do SHARE a far-related ancestor.
What is the point of an out-group?
A point of comparison for the in-group and specifically allows for the phylogeny to be rooted.
It also allows for a time scale of relatedness to be formed, and to see which traits are the oldest and newly inherited.
Define a clade, and describe the 3 different kinds of them.
Clade: group of species
See Doc, 1a:
1) Monophyletic group: includes a common ancestor and ALL of its descendants
2) Polyphyletic group: does NOT include their common ancestor.
3) Paraphyletic group: includes a common ancestor, but NOT all of its descendants.
Define these terms; node, branch (2 kinds), taxons, root, time scale, and focal group.
Node: point where a species diverges in new species.
Branch:
- Terminal = end of lineage
- Internal = connection of species
Taxons: species included in a tree
Root: common ancestor connecting ALL species in a tree (at the start) - allows for creation of time axis.
Time scale: calibrated using geological time based on FOSSIL records
Focal Group: group of interest (excludes outgroup)
