Chapter 15: Plant Evolution Flashcards
Geographic Isolation
Vicariance event
the splitting of an ancestral widespread lineage into two daughter lineages that were divided between two adjacent regions.
Redbud
- Split into two species Western and Eastern redbud.
- The Western redbud grows along streams to get water in the summer
- Neither species survives if planted in the other species habitat
Ecological Isolation
Sympatric speciation
Serpentine Soils
- The soil has a high magnesium content and plants can’t survive.
- The plants that can survive are unique and become reproductively isolated.
- For example Serpentine Arnica and heart-leaf arnica
Temporal Isolation
Something that can change the flowering time
Dutchmen’s breeches vs. squirrel corn
- Dutchmen’s breeches is an eastern United States species + the Columbia basin.
- On the east coast there is squirrel corn that flowers in a different season
Mechanical isolation in orchids (Catasetum)
- 4 species can be hybridized by hand.
- all for are pollinated by the same bees
- the pollinium is attached to different parts of the been
Physiological Isolation
The stigma of one species can block the pollination of another species
Hybridization
the process of crossbreeding between genetically dissimilar parents to produce a hybrid. It frequently results in polyploid offspring.
Introgression
two similar species that can crossbreed with each other.
Polyploidy
Cells don’t separate properly and create double the number of chromosomes
- over 40% of species may be polyploid for example fire weed
Asexual Reproduction
Some sterile species may be able to propagate themselves. For example dandelions and blackberries
Apomixis
asexual reproduction in plants, in particular agamospermy.
