Exam 3 Evolution

What is the 'Habsburg jaw'?

A deformity common to the Habsburg dynasty of 15th-17th century Europe.

What are model organisms?

Model organisms are species that are extensively studied to understand biological processes, including E. coli, yeast, Drosophila, C. elegans, Arabidopsis, and mice.

What is the effective population size (Ne)?

Effective Population Size (Ne) is the size of an idealized population that would experience the same rate of genetic drift as the real population.

How does inbreeding impact deleterious alleles?

Inbreeding increases the probability that deleterious recessives will be homozygous in an individual.

What is inbreeding depression?

Inbreeding depression is a decline in fitness due to the expression of deleterious recessive alleles.

What is genetic purging?

Genetic purging is the process where selection against deleterious recessives strengthens in a chronically inbred population, leading to the removal of these alleles over time.

What was the estimated Ne for the current Cheetah population?

The estimated Ne for the current Cheetah population is 15.4.

What is mutation-selection balance?

Mutation-selection balance occurs when the rate of introduction of deleterious recessive alleles by mutation equals the rate of elimination by selection.

What are the advantages of genetic rescue?

1. Increased genetic diversity 2. Decreased probability of identity-by-descent (IBD) and resulting inbreeding depression.

What are the risks of genetic rescue?

1. Potential replenishment of harmful recessive alleles reduces mean fitness. 2. Translocating individuals erases the distinctiveness of local populations.

What phenomena occurs when copies of the same chromosomal segments are inherited from a shared ancestor?

This is called identity-by-descent (IBD).

Why are genomes not riddled with deleterious mutations?

Purifying selection acts to eliminate deleterious mutations, and the stronger the deleterious effect of an allele, the stronger the selection pressure against it.

What was a finding from the 2017 study comparing ancient and modern mammoths?

The genomes of surviving Wrangel Island mammoths exhibited high rates of deletions, retrogenes, and non-functionalizing mutations.

Why is the study of emerging model organisms important?

Emerging model organisms can better address scientific questions than traditional models, especially with advances in sequencing and functional genomics.

What is identity-by-descent (IBD) in terms of inbreeding?

Inbreeding results in IBD when segments of chromosomes inherited from shared ancestors come together in an individual.

What is the time frame of the Precambrian period?

The Precambrian period lasted from about 4500 million years ago (mya) to 540 mya.

What were the major events in evolution during the Precambrian?

Major events included the origin of life, origin of photosynthesis, origin of complex cells (eukaryotes), origin of sex, and origin of multicellular life.

What hypothesis suggests that metabolism came before replication?

The 'Iron-Sulfur World Hypothesis' proposes that primitive metabolic pathways developed on iron sulfides.

What are protobionts?

Protobionts are aggregations of abiotically produced organic compounds in a lipid bilayer with different internal chemical environments.

What life form is believed to be the first evidence of multicellular life?

The earliest known form of complex, multicellular life from the Ediacaran period is soft-bodied organisms found in strata in South Australia.

What led to the Great Oxygen Event around 2400 mya?

The release of O2 into the atmosphere by cyanobacteria, which was toxic to anaerobic organisms.

What significant process allowed for the evolution of eukaryotic cells?

Eukaryotic cells arose through the fusion of prokaryotic cells, associated with the endosymbiotic theory.

Where did the oldest evidence of life come from?

The oldest life evidence is from sedimentary rocks on the east shore of Hudson Bay, Quebec, Canada, dating back 3.77 billion years.

What are the key components needed for the origin of life?

The key components include organic molecules (amino acids and nucleic acids), a metabolism to convert energy, and a replication mechanism for information transfer.

What is the significance of the Miller-Urey experiment?

The Miller-Urey experiment demonstrated that simple organic compounds can form from inorganic substances under prebiotic conditions.

What is the Biological Species Concept?

A group of organisms capable of interbreeding and producing fertile offspring.

What is a species?

A group of organisms that are similar in many biological ways and dissimilar from other species.

What percentage of living species are arthropods?

67%.

What does the Phylogenetic Species Concept define?

Groups of populations or lineages that share a unique combination of fixed character states.

What did Carolus Linnaeus contribute to taxonomy?

He developed binomial nomenclature and classified species into hierarchical ranks.

What is the Principle of Priority in taxonomy?

The oldest available name is the valid name of a taxon.

What is the main principle behind binomial nomenclature?

Each species is given two names: the genus name and the species name.

What is an example of hybrid organisms mentioned in the lecture?

Liger (male lion, female tiger) and Tigon (female lion, male tiger) are hybrids.

What is the difference between a taxon and taxonomy?

A taxon is any group of organisms, while taxonomy is the classification of living things.

What is the purpose of the International Code of Zoological Nomenclature?

To maintain standard naming conventions for animal species.