Midterm 1 Flashcards
Study
Evolution
Has genetic change occurred?
Change of alleles/genes through time.
Long term viability.
Natural Selection
Change in phenotype over generations.
Change in alleles across a population over time.
Five Types of Selection
- Stabilizing Selection (What exists)
- Directional Selection (One extreme)
- Disruptive Selection (‘Both’ Extremes)
- Fluctuating Selection (Back and Forth)
- Frequency-dependent Selection (Rarity)
Four Mechanisms of Evolution
- Mutation
- Gene Flow (Migration)
- Genetic Drift
- Natural Selection
Population
A collection of individuals of a single species
Community
All individuals of any species in an area
Genotype
The genes
Phenotype
Not the genes
Plasticity
Change in phenotype without genetic change.
Examples:
* Tanning skin.
* Stem Cells.
* Weight.
Sympatric Speciation
‘Same-Place’ Speciation.
Fitness is determined by other phenotypes or individuals (mating preference)
Allopatric Speciation
‘Different-Place’ Speciation
Geographic Isolation
Pre-zygotic Isolation
Selection before fertilization (Preferential use of sperm)
Post-zygotic Isolation
Selection after fertilization (low developmental viability)
Three Concepts of a Species
Biological
Typological
Phylogenetic
Darwin and Wallace
First Described Natural Selection
Mechanisms of Natual Selection
- Variation
- Differential Reproduction
- Heredity
Taxonomic Mnemonic
Dear King Philip Came Over For Good Soup
Taxonomic Order
Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species
Examples of Tradeoffs in Fitness
Peacock Tail (Secondary sex characteristics): Expensive and cumbersome, but impressive to mates.
Population Bottleneck / Founder Effect
When a small number of individuals are separated (usually geographically) into a new distinct population.
Founders of a new species.
Usually Results in a high occurrence of Genetic Drift.
Example of Mutation Evolution
HbS gene in Humans. Leads to Resistance to Malaria, but causes sickle cell anemia (if 2 recessives)
Example of Gene Flow Evolution
Caribou changing herds, or a bee carrying pollen to flowers from different populations.
Example of Genetic Drift
Population Bottlenecks leave a small random assortment of survivors and their genes.
Example of Natural Selection
Giraffe neck and the ability to reach food other animals can’t.
Natural Selection vs. Speciation
Speciation is a result of evolution.
Over time, a single species separated into two populations will evolve differently, eventually becoming unable to interbreed.
Natural selection is one aspect of the driving force behind these changes.
The Biological Concept of a Species
A group of organisms that can interbreed and produce viable, fertile offspring.
The Typological Concept of a Species
A group that shares certain characteristics, distinguishing them from other groups.
The Phylogenetic Concept of a Species
An irreducible group whos members are descended from a common ancestor.
Speciation
One population that, through reproductive isolation, becomes two populations that cannot interbreed.
Prezygotic Isolation
Two individuals are unable to or don’t mate.
Postzygotic Isolation
Two individuals can mate, but their offspring don’t develop correctly and die or are unable to have offspring of their own.
Scholastic World View
Ideal Forms.
Variation as a flaw, or a degradation of those forms.
Species are set and continuous by a creator.
Biblical Worldview
Independent Creation of Species.
Young Earth.
Evidence of Evolution (8)
- Homology
- Similarity of Proximal Species
- Adaptation (bad evidence against creation)
- Analogy
- Vestigial Features
- Fossil Record
- Genetic / Molecular Record
- Observation
Convergent Evolution / Analogy
Two (distinct) features with similar functions that are not shared in the common ancestor.
Example: Polar Bear & Arctic Hen Color
Homology
Two (similar) features with different functions are shared in the common ancestor.
Example: Donphin Fins & Human Hands
Gradualism
Evolutionary change that occurs gradually over long periods.
Example:
Punctuated Equilibrium:
Evolutionary stability for long periods, punctuated with small periods of rapid change.
Monophyletic
A group descended from a common evolutionary ancestor not shared by other groups.
Paraphyletic
A group sharing a common ancestor, but not including all descendants of that ancestor.
Synapomorphies
Ancestral characteristics, shared exclusively by that clade.
Sympliesomorphies
Ancestral characteristics, shared by two or more lineages of a clade, but are not exclusive to that clade.
Differences of Ancient Earth (6)
- 70-80% as bright.
- Lots of iron in the oceans.
- Lots of CO2, Ni / S compounds.
- Unfiltered Radiation. (No Ozone)
- Anoxic (No Oxygen)
- No Complex Organic Macromolecules.
Miller-Urey Experiment
- Abiogenesis
- CH4 (Methane), NH3 (Ammonia), H2 (hydrogen) + Electricity = glycine, alanine, and other amino acids.
Why is RNA considered older than DNA and Protein.
- Can store information and catalyze reactions. Jack of all trades.
- Ribozyme!
Eukaryotes vs. Prokaryotes
Eukaryotes:
Morphologically Diverse | Large
Prokaryotes:
Metabolically Diverse
Archaea / Eukaryote / Bacteria Division
Are Viruses Monophyletic?
- No
- Evolved many times separately, from all over the tree of life.
Why is prokaryotes vs eukaryotes outdated?
- Eukaryotes are a small off-chute of Archaea.
- Implies 50/50 relationship, when prokaryotes make up the vast majority of all diversity of life.
Why is Eukaryotes v Bacteria v Archaea outdated?
- Eukaryotes are a small branch of Archaea.
- Archaea aren’t monophyletic.
Chlamydias
Parasites of animals
Spirochetes
Spiral
Cyanobacteria
Photosynthetic
Gram-positive bacteria
Soil-dwelling decomposers
Alpha Proteobacteria
Ancestor of mitochondria
Beta Proteobacteria
Very diverse
Gamma proteobacteria
Symbionts or pathogens of humans
Delta proteobacteria
Some form fruiting body
Epsilon Proteobacteria
Many Symbionts or Pathogens
