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.
Population
A local group of interbreeding individuals.
The smallest level of life that evolves.
Sexual Selection
Mate preference.
Artificial Selection
Man’s impact on nature.
Aerobic Process
Metabolic process of prokaryotes.
Need Oxygen.
Anaerobic Process.
Metabolic process of prokaryotes.
Don’t need oxygen.
Oxygen may limit growth.
Chamoautotrophs
Use inorganic chemicals from their environment, such as iron ore, hydrogen, or ammonia as an energy source.
Extinction
The result of a species’ inability to adapt to adverse changes in the environment.
The idea of extinction was generated by fossils.
Pathogens
Organisms that cause disease in other organisms.
Host specific.
Exotoxins
Type of pathogen.
Secreted toxins that damage surrounding tissues.
Endotoxins
Type of pathogen.
Toxins within their cell walls/membranes, which triggers illness in the host organism.
Menthanogens
Anaerobic archaens that produce gas as a by-product of metabolism.
Extremophiles
Organisms that thrive in extreme environments.
Ex: thermophiles, halophiles, and acidophiles.
Speciation
One species splits to for two or more species that are reproductively isolated from one another by limiting gene flow.
Polyploidy
Rapid chromosomal changes.
Condition in which an individual has more than two sets of chromosomes.
Can be a result from Sympatric Speciation.
Biological Species Concept
Species are a group of natural populations that can interbreed to produce fertile offspring.
Binary Fission
How prokaryotes reproduce asexually.
A copy of the DNA is transferred to each of the daughter cells.
Very fast way to divide.
Limits to the Morphological Species Concept
- Separate species can look the same.
2. Members of one species may vary drastically but can still breed.
Hybrids
Offspring from distinct species that are able to interbreed in nature and are said to “hybridize”.
Sympatric Speciation
The formation of new species in the absence of geographic isolation.
The Importance of Cyanobacteria
- It originated photosynthesis.This process changed the atmospheric composition of earth by increasing the level of available oxygen.
- Some Eukaryotes took up cyanobacteria to become producers. Like Protists and Plants.
Why are Prokaryotes important memebers of all Ecosystems?
- Decomposers that are heterotrophic.
- Nitrogen Fixation.
- Fermentation.
- Bioremediation.
Rapid speciation event possible by…
- Introduction of organism to new niches (food types in one area) in an isolated geographical area.
- Mass extinction events.
- Evolution of significantly advantageous traits.
Atavisms
Ancestral traits reappear, presumable through dormant gene activation.
Vestigial Organs/Traits
They may take on new functions, or may become severely reduces.
Examples: pelvic bones in snakes and whales, vitamin C gene in humans and other primates.
Barriers to Reproduction (Reproductive Isolation)
- Pre-zygotic: prevent sperm and egg from gamete from successful fusion to form a zygote (no zygote/embryo).
- Post-zygotic: prevent zygotes from developing into health and fertile offspring (messed up zygote/embryo).
Allopatric Speciation
The formation of new species from geographically isolated populations.
These species that are formed from allopatric isolation may not remain geographically isolated.
Ring Species
Result of little gene flow between populations combined with geographic isolation.
Can develop when population loos around a geographic barrier; two ends of the loop are in contact with one another, yet individuals from those two populations cannot interbreed.
