Chapters 15, 17 and Evolution Flashcards
Uniformitarianism
(Hutton/Lyell)
Gradual changes over deep time.
Forces like erosion and deposition that we see today and have been going on since the beginning.
Catastrophism
Multiple extinction events that followed by influx and flourishing of previously uncommon species.
Evolution
Change in genetic variation in a population over generational time.
Not random.
Does not result in increased/more complex traits.
Generated by observation of similar traits, deep time, and extinction.
The result of selection on existing variation.
Lamarckian Evolution
Evolution determined by an organism’s action in their environment.
States that habits lead to changes in organisms; use/disuse.
States that organisms are unrelated.
Natural Selection
There is a common ancestor of all life.
Surviving variants pass on inherited traits (filtering mechanism).
The environment is the deriving evolutionary force.
Removes variation by favoring particular alleles.
Environmental pressures.
Linnaean Classification
Linnaeus built on previous systems to classify the immense diversity of life on earth.
Linnaeus used anatomy - organismal structure.
Linnaen freamwork is still used, but constantly updated and revised.
Modern Classification
- Geonomic analysis: studying the differences in gene sequences.
- Behavioral analysis
- Physiology
Genetic Drift
The removal of alleles from a population because of random causes.
This usually happens in small populations, individuals with new alleles might not mate.
This can result in a loss of adaptive alleles that natural selection (environment) might prefer.
Removes Variation by random removal.
Gene Flow
Exchange of genes between two population of a species.
An example would be that individuals from one population breed with members of another.
Generally maintains existing variations - reintroduces lost alleles.
Morphological Species Concept
Do these two creatures look the same? - It is based on shared physical characteristics.
It is used for fossils and asexually reproducing organisms.
Node
Represents the most recent common ancestor or all organisms that follow it in the tree.
Clade
What is made up from a given ancestor and all of its descendants.
Derived Traits
AKA Homologous Traits.
Traits that are obtained from a common ancestor.
Closely related species will share more derived traits than distantly related species.
Convergent Traits
AKA Analogous Traits.
Appears in two lineages, but was not in their most recent common ancestor - they evolved the traits separately.
Anatomical and physiological inconsistencies are apparent.
3 Domains of Life
- Bacteria: unicellular pokaryotes.
- Archaea: unicellular prokaryotes, have unique plasma membrane/cell wall components that separates them, occupy the wildest varieties of habitats.
- Eukarya: unicellular and multicellular eukaryotes.
6 Kingdoms of Life
- Bacteria (P)
- Archaea (P)
- Protista (E)
- Plantae (E)
- Fungi (E)
- Animalia (E)
Prokaryotic Cellular organization
Usually unicellular.
Some prokaryotes exhibit colonial organization.
Movement via the flagella.
Plasmids: free-floating circular chromosomes.
Limits of Evolution
- Species cannot actively change to meet their needs; variation must already exist in a population.
- Not all genes are possible; genetic constraints, developmental constraints, life-history constraints, or trade-offs.