chapter 20 (quick study) Flashcards
What is a phylogenetic tree?
A diagram showing evolutionary relationships among species.
Who introduced the concept of phylogenetic trees?
Charles Darwin.
What modern technology has changed how we view evolution?
Cladistics, DNA sequencing, and amino acid sequencing.
What is Horizontal Gene Transfer (HGT)?
The transfer of genetic material between unrelated species.
What are the three main types of HGT in prokaryotes?
- Transformation – uptake of free DNA.
- Transduction – virus-mediated gene transfer.
- Conjugation – gene transfer via a pilus.
Give an example of HGT in eukaryotes.
• Fungi acquired the Taxol gene from yew trees (used in cancer drugs).
• Carotenoid enzyme transferred from fungi to aphids, allowing aphids to produce their own carotenoids.
What does the endosymbiotic theory propose?
Mitochondria and chloroplasts originated from prokaryotes that were engulfed by early eukaryotic cells.
List three pieces of evidence supporting the endosymbiotic theory.
- Mitochondria and chloroplasts have their own DNA (similar to bacteria).
- They replicate through binary fission, like bacteria.
- They have double membranes, suggesting an engulfment event.
What is the Web of Life model?
A model suggesting that early prokaryotes exchanged genes through HGT, making evolution more network-like.
What is the Ring of Life model?
A model proposing that all three domains (Bacteria, Archaea, and Eukarya) evolved from a gene-swapping pool of prokaryotes.
What hypothesis suggests that gram-negative bacteria evolved from the fusion of an archaean and a gram-positive bacterium?
Genome Fusion Hypothesis.
