Origins of cells - evidence for evolution of life Flashcards
What is the Last Universal Common Ancestor (LUCA)?
An ancient common ancestor believed to have existed about 4 billion years ago.
What evidence suggests that different species have evolved from a common ancestor?
Species share similar characteristics, such as bone structure in vertebrate forelimbs.
How does DNA help determine evolutionary relationships between species?
Organisms with similar DNA sequences are more closely related than those with very different DNA sequences.
What are some pieces of evidence for common ancestry shared by all living organisms?
- Same biochemistry in all organisms
- Same DNA bases and genetic code
- Same shared amino acids forming protein molecules
What is the significance of phylogenetic trees in relation to LUCA?
LUCA would be the organism at the very base of the tree.
What dating technique uses carbon-14?
Carbon dating for samples up to approx. 60,000 years old.
What is radiometric dating?
A technique that measures the relative proportions of certain radioactive substances in a sample.
How can the age of an organism be determined through its genome?
By analyzing DNA mutations that accumulate over time.
What is a molecular clock?
A method to estimate the date when life on Earth originated based on DNA mutation rates.
Where is it hypothesized that LUCA evolved?
Near hydrothermal vents deep in the ocean.
What is chemosynthesis?
A process by which organisms generate energy using chemical reactions.
What ancient fossil structures have been found near hydrothermal vents?
Small tubes made of haematite, believed to be over 3.77 billion years old.
What characteristics might LUCA have had?
- Anaerobic
- Converted carbon dioxide into glucose
- Used hydrogen as an energy source
- Converted nitrogen into ammonia
- Survived in high-temperature environments
True or False: The hypothesis that LUCA evolved near hydrothermal vents is the only theory for the origin of life.
False.
What indicates that ancient bacteria had a similar biochemistry to modern iron-oxidizing bacteria?
The presence of carbonate and other carbonaceous material in sedimentary rocks.
What is the significance of the fossil structures found in Quebec, Canada?
They are among the oldest forms of life ever found, providing evidence of early life.
Fill in the blank: The descendants of LUCA would have ______ other species and shaped the tree of life.
outcompeted
What do fossil evidence and genetic analysis indicate about LUCA?
Fossil evidence and genetic analysis indicates that LUCA may have been an autotrophic extremophile that lived in hydrothermal vents, in an environment with an abundance of hydrogen, carbon dioxide and iron
