Evolution of plants Flashcards
In which eon did the oldest forms of life appear?
Archaean eon
Did plants discover photosynthesis?
No, they commercialized the invention of cyanobacteria in the form of chloroplasts
When did oxygenic photosynthesis originate?
Late Archaean
How do we know that endosymbiosis happened twice?
Mitochondria are an ancestral trait in eukaryotes, and chloroplasts are only in some
Which protists are the closest relatives to land plants?
Green algae and their sister group the charophytes
What traits would have been present in the common ancestor of green algae and plants?
Alternation of generations, multicellular, photosynthetic
What is the difference in the alternation of generations life cycle in green algae vs land plants?
Green algae have isomorphic generations, the generations in plants look different
What traits do the land plants have in common with charophytes?
Cellulose cell walls, store glucose as starch, chlorophyll a and b
What were the challenges for the first land plants?
Structural support, water loss, protection against UV light, gamete exchange, nutrients
Why would plants bother going on land?
More access to light and CO2, no predation, less competition
Why is allopolyploidy important in the evolution of plants?
It allows rapid speciation through the creation of fertile hybrids
What is allopolyploidy?
A polyploid where the multiple sets of chromosomes come from different species
Why are hybrids sometimes viable, but infertile?
They can’t pair up their chromosomes during meiosis, but that isn’t required for mitosis so they can do that just fine
Why is polyploidy common in plants?
Mitosis and meiosis are imperfect in plants, which ends with all the genetic material sometimes getting pulled into one daughter cell
What was one of the first plants to have vascular tissue?
Cooksonia (430 million years ago)
