Evolution & Origins of Life Flashcards
What is the RNA world hypothesis?
Early life thought to be based on self-replicating, self catalytic, RNA molecules
What are opsins?
G protein coupled receptors that convert light to nerve impulses
What are hCONDELs?
Regions of deletions in human genomes that are highly conserved in closely related relatives
How did eukaryotes arise?
Through endosymbiosis
How can phylogenetic relationships be represented?
Using phylogenetic tree diagrams
What is radiometric dating?
Measuring the ratio of parent daughter nuclides
Outline the order of appearance of cells in the fossil record
Prokaryotes -> Eukaryotes -> Multicellular organisms -> Animals
Define classification
Arranging taxa into an ordered, heirarchal system
What is the start codon present in bacteria?
A modified version called Formyl-methionine
Give examples of analogical structures
Insect wings and Bird wings
- different developmental mechanisms
- but have overlapping molecular components
Name the PAX6 homologs
Mouse - small eye
Drosophilia fly - eyeless
Humans - PAX6 aniridia
Why is the rate of radioactive decay constant?
It is not affected by the following factors
- temperature
- pressure
- chemicals
- electrical fields
- magnetic field
What can be determined using the fossil record?
The order and age of organisms
Give an example of analogical molecules
Crystallins (lens proteins)
many different transparent proteins in different species
all have different functions as well
provide stability, transparency and refraction
How has the diversity of cells increased so much?
The rate of diversification increases with multicellularity
What is molecular analogy?
Molecular evolution convergence
- proteins can have similar functions with no common molecular structure
How has the plastid genome evolved?
Has a loss of genes compared to its earlier form
The ‘lost’ genes are present in the nuclear genome
What are the 4 basic processes of multicellularity?
- spatial organisation
- change in form/ specialisation
- growth
- differentiation
How can mutations increase survival?
If mutation results in beneficial characteristics, the organism will survive better than its competition
What is the fossil record?
Rock and organic material dated by measuring decay of natural occurring radioactive isotopes
Approximately how many times has the cellular structure of eyes evolved?
Over 40 times - origin of eye components varies
What is a homeodomain?
Transcription Factors found in genes regulating morphogenesis in plants, animals and fungi
Give an example of a mutation tolerated by DNA
Sickle Cell Anemia (ScA)
- mutation in both β globin gene Glu6Val
- mutant Hb molecules aggregate and form crystals when deoxygenated
- results in cells with sickle shape
- cells get trapped in capillaries -> can cause tissue death
What do all bacteria, archae and eukaryotes have in common?
They all carry genetic material DNA
What is the function of the Drosophilia eyeless / PAX6 gene
Pax6/eyeless is involved in development of eyes & brain of both invertebrates & vertebrates
How do eukaryotes detect light?
Via Opsins
What are the consequences of gene duplication in evolution?
- Complementary functions (original and duplicated genes carry out same function)
- non overlapping functions
- Regulatory mutations partition the activity of ancestral genes
What are orthologs?
two genes from different organisms that have arisen from a common ancestor
What is the start codon used in archae & eukaryotes?
Methionine AUG
Why is radiometric dating an accurate way to determine age?
Parent and daughter nuclides cannot leave or enter materials once they have formed
There is no intrusion of other, later rock
No contamination