Exam 3 Flashcards
Homology is established though similarities in developmental pathways, specifically _________.
embryos
What did German biologist Ernst Haeckel tie similarities in developmental pathways to?
Evolutionary Change
What does “Ontegeny Recapitulates Phylogeny” Mean?
development of an organism (ontogeny) expresses all the intermediate forms of its ancestors throughout evolution (phylogeny)
What are genes that control where, when, and how other genes are expressed?
Master Genes
Homeotic Genes are type of _________. What do they regulate?
- Master Genes
- Regulate expression of body parts by regulating where, when, and how genes downstream will be expressed.
HOX genes are a type of __________. What do they do?
- Master Genes
- Set up Anterior-Posterior and Dorsal-Ventral Axes
HOX genes are arranged in what way on chromosomes?
Co-linear
What is evidence for the importance of HOX genes?
They have been conserved over time
What genes spur eye development?
PAX genes
While the same homeotic genes can occur in several species, variants in the regulatory genes can still arise through ________ ________.
Random Mutation
What acts to shape the effects of mutations in homeotic genes in terms o fitness and frequency within the population?
Selection
What is the most important source of new genes?
Gene duplication
What is the term that means more copies of all genes?
Polyploidy
What causes unequal crossing over so that one chromosome gets extra copies of a gene?
Misalignment in meiosis
What are three consequences of gene duplication?
- New copy may not have the same functional constraints as the ancestor copy
- Mutations may accumulate in the new copy with fewer consequences
- Mutations may allow the new copy to perform new functions
What are gene families and what are two examples?
- Clusters of genes similar in structure and sequence
- HOX genes, Globin Genes
The Globin Gene family includes _________, which are non-functional as globin genes and are usually not transcribed.
pseudogenes
Selection acts ________ on each gene in a gene family.
Independently
How long ago did earth form?
3.6 billion years ago
What is the period called from the origin of the solar system to about 3850 ma and what are two characteristics?
- The Hadean
- No fossil record
- Almost no geological record
What are four key events from the Hadean period?
- Differentiation of earth into crust, mantle and core
- origin of the atmosphere
- condensation of water vapor
- Origin of continental crust
What are three attributes of life?
- Autonomous replication
- Critical level of complexity
- Ability to evolve via natural selection
What are requirements for life?
- An energy source
- Basic chemicals
- An external environment that sustains life
In what era and eon was the origin of life?
Eon: Archean
Era: Eoarchaen