Final Exam Flashcards
What is Evolution?
Descent with modification
3 people who proposed populations of organisms changed over time in ancient times?
Anaximander (6th Century BC) - species formed from water, humans descended from fish
Empedocles (5th Century BC) - heads, limbs & organs joined at random, only some combinations fit for survival
Plato (4th Century BC) - each natural object in observed world is imperfect manifestation of ideal
Describe the Theory of Special Creation
- Created by a Deity
- Species created independently of one another
- Species remain unchanged since their creation
- Variability within a species is minor/limited
- Creation event occurred 26th October 4004 BC @ 9:00 am
Who proposed the Theory of Special Creation?
Archbishop James Ussher (1581 - 1656)
Who is Carolus Linnaeus and what did he do?
Swedish naturalist, classified plants based on morphology into Kingdom, Classes, Orders, Genus & Species
Introduced system of nomenclature for species identification (genus name + species name - used to this day)
What did Erasmus Darwin contribute to the Theory of Evolution?
“The final course of this contest among males seems to be, that the strongest & most active animal should propagate the species which should thus be improved”
What did Jean Baptiste Lamarck contribute to the Theory of Evolution?
Lamarckism - all species derived by gradual change from other species, inheritance of acquired characteristics
Organs become improved if used a lot, reduced to vestiges from disuse. Require bodily changed have a way to be registered in germ cells
Difference between Catastrophism and Uniformitarianism
Catastrophism - biblical interpretation of the history of the Earth (Earth created by supernatural means approx. 6000 years ago)
Uniformitarianism - modern view of Earth’s history (unimaginably old, landforms result of geological processes still occurring today - James Hutton)
What did Charles Lyell contribute to the Theory of Evolution?
Challenged prevailing beliefs regarding Earth’s history & age - argued Earth is hundreds of million of years old - geology created by natural forces
3 observations from Darwin’s trip down the East coast of South America
- Species can/do go extinct (fossils of animals no longer extant in region)
- Species have ancestors & change through time (fossils of animals in region different from modern day equivalents)
- Species differ across space/geographical distance (travelling North to South, species replaced by similar, but slightly different species)
What are the 2 model organisms Darwin used in the Galapagos?
- Tortoises
- Finches
What are Vestigial Organs?
Functionless/rudimentary versions of a body part that has an important function in other, closely allied species
What is Homology?
The same organ in different animals under every variety of form and function
What is Artificial Selection?
Over time humans have modified species to suit their needs through careful breeding programs - “caused” evolution of several species from single ancestral species
What was Thomas Robert Malthus’ main idea?
Reproductive capacity of human population exceeds food supply available to nourish expanding population, humans compete among themselves
Struggle exists in nature - constitute “natural” selection process
What is Wallace’s Line?
Line separating Indonesian islands (species different on either side)
When was “The Origin of Species” published?
24th November, 1859
What is the Linnean Society of London?
Forum of discussions on genetics, natural history, systematics, biology & history of plant/animal taxonomy
Regarding his theory of natural selection what two pieces could Darwin not explain?
- How a given trait is transmitted from parent to offspring?
- Where/how new traits suddenly appeared?
What are the 2 principles of Gregor Mendel’s work?
- Principle of Segregation - each gamete can carry only one allele from a parent at a given gene
- Principle of Independent Assortment - segregation of members of one pair of alleles occurs independently of the segregation of the members of another pair of alleles during gamete formation
Simple definition of Microevolution
Species change over time
Simple definition of Speciation
Lineages split & diverge
Simple definition of Macroevolution
New lifeforms derive from older forms
Simple definition of Common Ancestry
All lifeforms are related
What are 2 examples that show Microevolution?
- Selective Breeding (Artificial Selection)
- Vestigial Structures
What is the Biological Species Concept?
Species are populations, or groups of populations within and among which individuals actually or potentially interbreed and outside of which they do not interbreed
What 2 examples show the existence of Macroevolution?
- Extinction & Succession
- Transitional Forms
Difference between Homology & Analogy
Homology - if they are derived, evolutionarily & developmentally, from the same source structure
Analogy - if they have similar functions but are derived evolutionarily & developmentally, from different source structures
What is the definition of Evolution?
Change in genetics/allele frequency in a population over time
What are the 5 mechanisms of Evolution?
- Natural Selection
- Mutation
- Genetic Drift
- Gene Flow
- Non-Random Mating
What are the 4 postulates of the Theory of Evolution by Natural Selection?
- Individuals of a population differ from one another
- The differences are, at least in part, passed from parent to offspring
- Some individuals are more successful at surviving & reproducing than others
- The more successful individuals are not merely lucky; instead, they succeed because of the variant traits they have inherited & will pass to their offspring
What does natural selection act on?
Phenotypes
What is Fitness?
Ability of an individual to survive & reproduce in its environment
What is fitness compared to?
Relative to fitness of other members of a population
What is an Adaptation?
A trait that increases the ability of an individual to survive & reproduce compared with individuals without that trait
What is a Trait?
Any characteristic of an individual ranging from outward appearance to molecular characteristics
General Summary of Natural Selection
Alleles associated with higher fitness increase in frequency from one generation to the next
What is Differential Selection?
Probability of surviving is linear with an increase or decrease in a trait
What is Stabilizing Selection?
Probability of surviving increases closer to the mean
What is Disruptive Selection?
Probability of surviving increases with departure from the mean
Where are the 3 ways variation in an individual can occur?
- Environmental Variation - phenotypes different from exposure to different environments (epigenetic)
- Genetic Variation - different genotypes cause different phenotypes
- Genotype by Environment Interaction
What is Phenotypic Plasticity?
Refers to the fact that genetically identical individuals can have different phenotypes in different environmental conditions
What is the Reaction Norm?
Refers to the pattern or range of phenotypes that the same genotype can possess as a result of different environments
What is the ultimate source of genetic variability?
Mutations
What kind of impact do mutations have on their own to population allele frequencies
Low
2 main causes of mutation
- Mutation due to DNA alteration
- Mutation due to DNA copying error
What is a Point Mutation? And what does it result in
Single base pair changes resulting in new alleles
What is a Transition & Transversion? And what is more common?
Transition - purine –> purine, or pyrimidine –> pyrimidine
Transversion - purine –> pyrimidine (vice versa)
Transitions are more common
3 mutations resulting from point mutations
- Synonymous - no change in amino acid (due to redundancy in genetic code)
- Non-Synonymous - change in amino acid
- Nonsense - premature STOP (non-functional protein)
2 methods of new gene formation
- Gene Duplication
- Derived from Scratch
2 Mechanisms of Gene Duplication
- Unequal Crossing Over - have same introns as original gene, and occur in tandem with original gene
- Duplication by Retroposition - new copy of existing gene, usually a pseudogene, can gain function with addition of regulatory sequence
2 Types of Chromosomal Mutations
- Inversions - gene order flipped
- Genome Duplication - polyploidization