Mating Systems Flashcards
Aphids, parasitic wasps, mites, certain crustaceans, the majority of vascular plants all have what in common?
Do not reproduce sexually every generation
Cnemidophorus sp. (Whiptail lizards) Geckos Pocelliopsis sp. (stream fish) Snails Fungi and Protozoa
All of these have what in common?
They never reproduce sexually
The bellidoid rotigers, (small freshwater invertebrates) nerve reproduce asexually. This is an entire animal phylum that doesn’t
!
In whiptail lizards (6 of 15) what is required for the female to reproduce?
Another female courts her by a typically male pattern
What is the way in which some whiptail lizards reproduce called?
Pseudocopulation
T/F: nearly every eukaryote has a life history of sex
True
What mechanism would be capable of producing an adaptation like sex?
Natural Selection
Natural selection favors individuals that pass on their genes to the next generation, but in most species the males contribute nothing but sperm to reproduction
!
A parthenogenic (no fusion of male and female gametes) female should have the advantage, as shse passes on twice as many of her genes with each offspring
!
If there were a genetic polymorphism in a population, would asexual or sexual females have the enormous fitness advantage?
Asexual females, especially since in most species males contribute nothing but sperm
Sexual displays and rituals can be enormously expensive in terms of energy, time, and resources
Sex is expensive (preach)
Ex: male bower birds spend weeks constructing bowers solely for the purpose of attracting males
Ex: females are ridden by males after copulation, sometimes for many hours. It intereres with the foraging of the females and places them at increased risk of predation
Sex is expensive! (preach)
Ex: Tree frogs in Central America call to attract mates. Females are strongly attracted to the calls, it is much easier to get a mate if a frog invests a lot of time calling.
Carnivorous bats are also attracted to the calls, and they pluck the male right off the tree
Sex is dangerous!
Ex: Calling cricket males are more attractive but parasitic flies hone in on the sound and deposit their eggs into the singing males
Sex is dangerous!
There are a few very compelling reasons why species might benefit from sexual reproduction
The problem is that we lack a real understanding of how selection works at the species level. Natural selection, as we know it, works on _____ not species
alleles
Genes that act for the good of the species could be undermined by selfish mutations that crop up within the individuals and spread
!
The move comprehensive and persuasive mechanism for the existence of sex it the
Red Queen Hypothesis
A mechanism for the continued existence of sexual reproduction. Proposes that even species that do not seem to be changing are undergoing rapid evolution.
Red Queen Hypothesis
The natural world is so challenging that without constant evolution, species would go extinct. What provides the necessary variation that keeps evolution going? (2)
If not for these two things, all species would go extinct if environmental change were to occur
Sex and Recombination
Every species on the planet is locked in what JBS Haldane referre to as…
Evolutionary Arms Race
The natural enemies-parasites, predators, and competitors, of any species evolve every generation to better exploit their hosts, capture their pray, and push aside their competitors.
This produces a ____ among the hosts, prey and predators to negate these advantages
Selective Pressure
The Red Queen hypothesis is a natural outgrowth of the
Evolutionary Arms Race
Braconids parasitizing a hornworm larva
A harvestman parasitized by mites
Long-term evolutionary arms races are suggested in the
Fossil Record