chpt 7&8 key concepts Flashcards
Asexual Advantages & Disadvantages
adv- offspring contribute wholly to fitness of parent
dis- mutation only variability
Sexual Advantages & Disadvantages
adv- creating gene variation
adv- purging harmful mutations
adv- increases variability
dis- costly to the individual (each offspring contributes only 1/2 fitness and they have trouble finding mates)
Cost of Reproduction for Males and Females
fem- more energetically costly gametes because they are larger
male- less energetically costly gametes because they are smaller
Limitations for Males and Females
fem- limited by resource access
male- limited by mate access
Conditions Favoring Hermaphrodites
low mobility
-limiting male to male competition
low overlap in resource demands by male and female structures
Principle of Allocation
organisms use energy for one function, the amount of energy available for other functions is reduced
Plant dispersers and seed size
seed size variation explains variation in plants
-larger seeds produce larger seedings
Six dispersal strategies
- Unassisted: no special structures
- Adhesion: hooks, spines, or barbs
- Wind: wings, hair, resistance structures
- Ant: oil surface coating
- Vertebrate: fleshy coating
- Scatterhoarded: gathered, stored in caches
Seed Size
small seed size
-variation has major implication for the performance of the offspring
-stay dormant longer
-seed unassisted by dispersal or wind
large seed size
-dispersed by hoarders
r-selected
per capita rate of increase
characteristic high population growth rate
K-selected
carrying capacity
characteristic efficient resource use
population attributes for r-selected
-a high intrinsic rate of increase
-not favored competitive ability
-rapid development
-early reproduction
-small body size
-single,semelparity reproduction
-many, small offspring
population attributes for k-selected
-low intrinsic rate of increase
-highly favored competitive ability
-slow development
-late reproduction
-large body size
-repeated reproduction
-few,large offspring
Grimes
proposed two most important variable exerting selective pressures in plants
Intensity of distrubance
any process limiting plants by destroying biomass
Intensity of stress
external constraints limiting rate of dry matter production
Ruderals
-highly disturbed habitats
-grow rapidly
-produce seeds quickly
Low distrubance
-low stress
-grow well but eventually compete with others for resources
Stress-tolerant
-high stress-no disturbance
-grow slowly-conserve resources
Promiscuous
individual mates with multiple partners and do not create a lasting social bond
Polyandry
an individual female breeds with multiple males
Polygamous
individual of one sex forms long term social bonds and mates with more than 1 individual of opposite sex
Polygyny
male mates with more than one female
Monogamy
a social bond between one male and one female persists through the period that is required for them to rear their offspring
Parental Care
enhances the survival of individual offspring
-feeding their young
-thermoregulation of young
-protection of young
-the teaching of young
Parental Care of Fish, Amphibians, and Reptiles
-little post-fertilization care except toads
Parental Care of Mammals
-females responsible, they carry young
-males do not heelp
-most mammals are self sufficient at birth
Parental Care of Birds
-both parents demand incubation and immobility of hatchling (monogamy)
-equal partitioning but separate nests
-females inseminated once, lay eggs, and leave while males raise nest while females lay a second nest and raise it
Emancipation of Males
allow males to increase fitness through multiple matings
Reasons of Sexual Dimphorphism
-trade-off of the energy
-roles in the mating choice
-basically why males and females have different traits
Sexual Selection
differences in reproductive rates among individuals as a result of differences in mating sucess
Good genes hypothesis
individual chooses a mate that possess a superior genotype
good health hypothesis
individual chooses healthiest mates
Runaway sexual selection
females persistently choose the most extreme male phenotypes
Handicap Hypothesis
-elaborate sexually selected displays and adornments act as handicaps
-show high fitness of bearer
-excess of resources
Parasite Mediated Sexual Selection
females choose mates without parasites because they want to develop high quality traits
Extra-Pair Copulations
males: increase the number of offspring with little increase in parental care
females: find a male with the best territory but may not have the best genes
