Lecture 6 Flashcards
Where do genetic recombination events occur?
eukaryotes only
What is fitness?
the ability to grow, survive, and reproduce
Why do many eukaryotes also reproduce asexually?
- if there is no one to mate with
- if resources are limiting
- speed purposes
- if things are doing good for that genome in that environment, wouldn’t want to change it, so would produce asexually
What is the nursing effect in eukaryotes when they reproduce asexually?
What are the benefits of sexual reproduction for eukaryotes?
- sexual reproductio enhances the potential for evolution in multiple ways
- enhanced genetic diversity despite longer generation times
- multiple different alleles of each gene present within a population
- dominance/recessive
- potential for polyploidy
what is the tradeoff that eukaryotes experience for longer generation time?
there would be evolutionary pressure to enhance genetic diversity in the next generation
what is mitosis?
daughter cells have almost identical genotype to original cell, and same number of chromosome pairs
what is meiosis?
homologous chromosomes synapse, some chromatid sections cross-over (genetic recombination) and the resulting pairs are separated (independent assortment) into four genetically different haploid cells (gametes or spores)
what allowed for the evolution of meiosis?
the presence of diploidy
What are three distinctive speciation mechanisms in eukaryotes that arise from initial diploidy?
- hybridization
- autopolyploidy
- allopolyploidy
What is hybridization?
- n+n
- speciation mechanism
- will lead to a new species if it evolves in reproductive isolation
What is autopolyploidy?
- 2n x 2
- speciation mechanism
- a eukaryotic cell going into division duplicates the chromosome before the cell becomes two daughter cells.
- if there is a mutation where the cell does not split apart, would cause the cell to have twice the number of chromosomes
What is allopolyploidy?
- (n+n) x 2
- speciation mechanism
- GET DEFINITION
what is alternation of generations?
- multicellular haploid and diploid phases
- happens in plants and some algae
- alternate between two different life stages
Why have different life cycles evolved?
- evolutionary trend
- diploidy generates and stores more genetic variance
- expanded diploid phase
- reduced haploid phase
*go back to slides and understand, because unsure
What are the protists?
- paraphyletic group
- most live in moist or aquatic habitats
What are the photosynthetic protists?
- plant like organisms, but lack true roots, stems, or leaves
- generally photosynthetic
- generally aquatic
- lack vascular tissue or a cuticle
how is light energy related to wavelength?
light energy is inversely proportional to its wavelength
what are algae functionally equivalent to?
plants on land due to similar ecology q
