Lecture 18 sex, reproductive systems and evolution Flashcards
What are the two reproductive systems and their definitions?
Asexual(making clones of themselves, violation of Mendel laws) and sexual (separate sexes or hermaphroditic)
What are the two sexual systems and their definitions?
Dioecious (male and female organs in separate organisms) and hermaphroditism
What are the two mating systems and their definitions?
Cross-fertilization (mating with other organisms and self-fertilization (mating with yourself)
What is sexual reproduction?
When two parents contribute genetic material to offspring
What does sexual reproduction involve?(2)
Meiotic reduction division to form gametes (a division of a cell to one haploid)
Fusion of gametes (when the sperm and egg meet)
What is a asexual reproduction?
Only one parent contributes genetic material To offspring
Is meiotic reductive division required in asexual reproduction?
No
What are offspring like in asexual reproduction?
Offspring are genetic replicas of parent (look identical to parent)
What was Darwin’s view of sex?
We don’t know the cause of sexuality or why two gametes should fuse together, the whole thing is a mystery
How do Eukaryotic organism reproduce?
asexually rather than sexually
How do eukaryotes reproduce in cooler water?
Asexually
How do eukaryotes reproduce in warm water?
Sexually
What is the relationship between reproductive systems and the environment?
Different reproductive systems occur in different environments
Many perennial plants reproduce through both sexual and asexual reproduction. What are they considered because of this?
An invasive species
What are the costs of sex?(5)
Time and energy to find and attract mates (dating cost)
Risk of predation and infection (by going out to finding mate rather than reproducing with yourself)
Cost of producing males
50% less genetic transmission
Break up of adaptive gene combinations; segregation and recombination
What are the benefits of sex known as a paradox?
Why it has evolves even though it is cons
What is Two fold
cost of meiosis?
Sexual females contribute only 50% of genes to population
What is transmission biases?
when one trait is more likely to be copied than the other
What does transmission bias favour?
Asexuals in female competition
What is the relationship between asexual reproduction and alleles?
Asexuals reproduction maintains favorable combinations of alleles
What is the benefit of the AA allele combination?
AA helps adapt to wet environments
What is the benefit of the aa allele combination?
aa helps adapt to dry environment
What is the benefit of the Aa allele combination?
Aa helps adapt to neither wet or dry environments
What is a con of sexual reproduction regarding alleles?
can continuously recreate undesirable combinations of alleles
What are Hypotheses for the advantages of sex?(3)
Bringing together favourable mutations
Eliminating harmful mutations
Aids in genetic Variation
What is the tangled bank hypothesis?
sexually reproducing species have an advantage over asexual individuals in the amount of offspring they can produce in a particular environment
Which form of reproduction causes favourable variations of mutations to be brought together more rapidly?
During sex
What are Asexual Oenothera?
species are diploidand do not need chromosome segregation and recombination during meiosis
What do Asexual Oenothera have and what is the con to this?
Have more premature stop codon mutations
Leads to dysfunctional proteins
What do dysfunctional proteins in Asexual Oenothera imply?
Higher rates of protein sequence evolution
Implies greater accumulation of deleterious mutations
Why is cloning yourself the best option in a homogeneous environment?
cloning yourself may be the best strategy because lack of diversity suggest selection has built up the optimal genotype
Which type of reproduction method do heterogenous environments favour?
Sexual reproduction