Sex & Reproduction Flashcards
Asexual
Sexual reproduction
Clone
Parthenogenesis
Apomixis
Hermaphrodite
Explain the roles of asexual and sexual reproduction in Daphnia in relation to environmental conditions
The daphnia water flea is asexual in the summer because of good conditions but sexual in poorer conditions
What are the benefits of sexual reproduction?
Sex is a driver of evolution
What are the costs of sexual reproduction ?
It is prone to failure
It is relatively inefficient when compared to asexual reproduction
Need a mate (a successful one)
Infertility issues
What are the benefits of asexual reproduction?
Simple
Less likely to fail
Might be more advantageous at the time
What are the costs of asexual reproduction?
What is fission? (asexual reproduction)
Division into two equally-sized offspring e.g. sea anemone
What is budding? (Asexual reproduction )
Unequal division into smaller offspring e.g. Hydra (relative of jellyfish)
What is fragmentation? (Asexual reproduction)
The parent breaks into many new individuals e.g. Kalanchoe (plant)
What is phylogeny?
“Evolutionary descent with reflected levels of genetic similarity because of shared evolutionary history”
What is the R-number?
The reproduction number!
E.g. if r = 2, the population doubles per generation
Commercial bananas are genetically identical to each other, what does this mean for them?
They can’t evolve quickly
Pathogens can adapt and evolve quite quickly, why is this?
Short generation times
Large numbers of progeny
Vast. Numbers offers many new opportunities for new mutations
What would it mean if all humans were genetically the same, how easy would it be to catch diseases and viruses?
Why does sex help?
If one person was susceptible to the disease everyone else would be too!
Sex means that everyone isn’t identical, if we were to become asexual then this would be a problem.
What is the Red Queen Hypothesis?
Must keep running to stand still
A species must continue evolving as their predators are evolving
Polyspermy meaning?
Totipotent
Cells that have potential to make all the cell types of an organism!
What does it mean if a cell is terminally differentiated?
A fixed single cell type
What are the main steps of fertilisation, how is polyspermy avoided?
What (simply) is morphogenesis?
The generation of shape, pattern and form
What is meant by monoblastic, (radical) diploblastic and (bilateral) tripoblastic?
Monoblastic organisms have no symmetry in their structure.
Radical diploblastic - radially symmetrical
Bilateral tripoblastic - three symmetry lines (have an anterior end and a posterior end)
What does it mean if we have an anterior and posterior end?
Food goes in one hole and waste comes out another.
