Bio 120 Key Vocab

Define Evolution

Change of inheritied genetic traits of population across generations leading to speciation/change in species.

Who created the natural selection theory?

Charles Darwin and Alfred Russel Wallace

What was Lamark’s theory of evolution?

Phenotypes were inherited by generation. This was proven wrong as genetic traits are inherited instead.

Define Argument from Design in relation to Evolution

Complexity of organisms and order implies existence of a creator. Natural selection disproves this by showing that complexity can arise without an intelligent creator

Define Population Thinking and its significance

Thinking that showed the importance of uniqueness and variations between individuals of same population rather than treating differences as negative

Define Modern Synthesis

Fusion of Darwin’s theory of natural selection w/Mendel’s Laws of Genetics.

Evolution = change of gene frequencies within population over time.

List Darwin’s Postulates

1. Individual’s traits in populations varies

2. Trait variation is inherited

3. If there is more offsprings than environment can support → struggle for survival

4. Successful survival/reproduction depends on inherited traits

List the 2 types of evolution

Microevolution + Macroevolution

Define microevolution

Change of inherited traits of one generation leading to accumulation of change for evolution caused by high phenotype variation

Define macroevolution

Change of inherited change over time across species

List the 2 evidences for macroevolution

• Geographical/Temporal Succession: Factor of natural selection (environment → competition → evolution)

• Transitional Fossils: Fossils of species that has common traits with BOTH ancestral + present species= explains gaps of evolution

Define artificial selection

Human process of generating desirable traits by selectively choosing species to inbreed.

What are the factors for evolution to occur?

1. Heritability

2. Genetic Variation

What are the methods for genetic variation?

1. Mutation

2. Recombination through Independent Assortment during mitosis

List and define the different types of Mutation

• Point Mutation

  • Most common type

  • Replacing 1 single nucleotide during DNA replication

  • Can be deletrious (harmful) or neutral (because of degenerate code) or beneficial

• Indels (Addition/Deletion)

  • Causes frame-shift mutation.

  • Deletrious/Beneficial → protein synthesis

• Inversions

  • Caused by double DNA breaks and broken segment flips and joined by DNA ligase

  • Loss of protein function

List 4 characteristics of mutation

1. Mutation = inevitable due to high number of genes cells need to copy + proofread

2. Mutation ≠ result of environment. Occurs randomly

3. Mutation is rare. Rarity depends on type of mutation

4. Environment can affect mutation rate (ex: mutagens)

How is the rate of mutation in unicellular and multiceullar organisms different?

Multicellular organisms have higher mutation rate than unicellular due to higher # of cells

Define natural selection

Process where advantagous phenotypes are selected for being more fit for survival/reproduction

Define phenotypic plasticity

Ability of genotype to express different phenotypes. Could be as a result of different environment or respond to external stimuli.

Define and state the importance of homology

Similairity in structure, genetic sequences, and behaviors between different organisms due to shared ancestry. Important for evidence of evolution and developing medicine by using model organisms (related organisms) to humans to test medicine.

State the 2 evidences for homology

• Pseudogenes

  • Repetitive non-coding DNA in genome

• Vestigial limbs

  • Organs/limbs that once had function in ancestoral species but is now reduced/no longer useful in function (ex: goosebumps and appendix in humans)

Define genome and phenome

Genome: All genes of organism

Phenome: All phenotypes (observable characteristics) of organism

Define Gene flow (Migration)

Transfer of genes/alleles from one species to another via inbreeding. Increases genetic diversity (more phenotypes) + reduces proportion of specific genes in new/old popultion. High gene flow = the 2 diff species/populations become more similar to eachother

Define Genetic Drift

Change in the frequency of an existing allele due to random chance. Especially important for smaller populations

Define fitness

Organism’s ability to survive + reproduce to pass its genes to next generation.

Define differential fitness

Different rates of survival/fitness between individuals in same population.

Define sexual selection

Type of natural selection where organisms compete for mates.

Define sexual dimorphism

Differences in physical traits/behavior between male/female individuals of a population for sexual selection

Define intrasexual competition and importance of mate choice

Competition between same sexes in population for mate. Strong mate choice ensures for better fitness in offspring for more survival/reproduction.

Distinguish between discrete and continuous traits

Discrete: Distinct + seperate categories. No intermediate. (ex: blood type)
Continuous: Spectrum/range of measurements (ex: height)

Define quantiative genetic inheritance

Study of how multiple factors contribute to shape physical traits in a continous spectrum rather than discrete ones.

List the factors for Quantitative Traits

1. Polygenic inheritance

2. Enviornmental factors

Define polygenic inheritance

Genetic process where 1 physical traits is controlled by one or more different genes working together (ex: eye colour/hair)

List and define the three different types of selection

• Disruptive

  • Extreme sides of both ends of phenotype are favoured. Causes 2 distinct groups of population.

• Stabilizing

  • Average phenotype favoured. Variation decreases as extreme traits removed

• Directional

  • 1 extreme phenotype favoured. Variation slightly decreases as other extreme side removed.

List 4 conclusions from Mendel’s Pea Experiments

1. Inheritance is determined by discrete traits (genes)

2. Each diploid org has 2 copies of same allele (dominance/recessive)

3. Gamets fuse to make offspring

4. Offspring inherit 1 gamete from each parent randomly (1 allele per gene from each parent)