topic 7 Flashcards
what is sexual selection
a form of natural selection that favors the evolution of elaborate traits in one sec and preference for those traits by the opposite sex
elaborate courtship displays ad/ or morphological traits common in males to serve the purpose of attracting females and discourage rivals
what is a common outcome of sexual selection?
morphological and behavioural differences between two sexes of the same species
what is a common outcome of sexual selection?
morphological and behavioral differences between two sexes of the same species. overall there exists a variation is a reproductive success ina population too
what is intersexual selection
mate choice
when one sex has a preference for members of the opposite sec which have certain traits
what is intrasexulation selection
mate competition
members of the same sex will compete to acquire access to mating opportunities with members of the opposite sex
fundamental asymmetry of sex
the concept that males have abundant, replenishable small sperm but females have a limited resource of large eggs
what is the biased operational sex ratio
the male: female gamete ratio. the fundamental law of asymmetry
further females have a lower sexual activity level whiles males have a higher level
how does honest signaling play into mate selection
-honest signals convays a message to the female about the quality of the male
what are the kinda of fitness benefits to mate selection
direct and indirect
indirect benefits from mate selection
the fitness of the females offring will be increased if males are preferable. this is a genetic benefit
direct benefits from mate selection
choosy females will gain fitness as they will gain advantage material. protection and resources from the male.
what is a typical result of intrasexual selection
sexual dimorphism is commonly tailored to the ability to fight and win combats against other males.
results in size differences between males and females. larger males are more likey to win during fights
what are armaments
these are weapon-like structures that males will develop to engage in combat
dominance hierarchy
a sorting method base on the results of male fighting
what is a negative towards intrasexual selection
fighting is very costly. often males will sued threat displays to mitigate the possibilities of fighting.
this can be audio, visible or hierarchical
mating systems
Patterns exhibited in a population in relation to their reproductive behavior
encompasses diff between male and female reproduction investment
what are the 5 mating systems
monogamy
polygyny
polyandry
polygynandry
promiscuity
monogamy
only one mate in a life time for both sexes
polygyny
males breed many times during mating season. femlaes will commonly breed once
polyandry
females have many partners while males will mate once
polygynandry
both males and females have several partners for who they share bonds with
promiscuity
males and females have many partners but no bond form
what are co-occurring species
speices that share the ability to live and reproduce in similar environ conditions
where will organimasn live// occupy
areas/ landsapces which the environ conditions match the niche requirement of the species
what happens when niches overlaps
in many cases if speices are able to exists in. thesame area with over lapping niches they will differ in thier life history:
number and size of offspring
timing of reporduction
patterns of survival
what is an ecological niche
a range of abiotic/ biotic facotrs that permit a species to survive and reproduce
fundamental Niche
the entire set of conditions under which a species can survive and reproduce
realized niche
the actual set of conitiond/ areas that a species is found, commonly influenced by biotic interactions and food availability
generalist vs specialist speices
generalist will tend to have lower populations ize but have a greater ability to utilize to wide variety of resources/ conditions.
specialist will be concentrated in a special environment and will have a limited conditions/ resource they can tolerate
how can species reduce competition is overlapping niches
by partitioning the niche. in many cases this will be due to the inability of species being able to coexist.
this may result in a narrowing of niches or a shift of niches
ex. galapagoes with diff sized beaks eat diff sized seeds to remain in the same area. they partiotn the food resource to reduce comp and both species will benefit from an increased fitness
what is convergent evolution
speies that occupy similar niehces and as a result will adapt and evolve in similar ways due to the selective pressures they experience. in many cases they will resemble each other
what is life history
how and when an org grows, develops, reporduces and survives
encompasses longevity
rate of repordutoin
offspring sie
timing of repdict (seasonally and age0
typ of report (asex or sex_
what is an semelparous speices
those that breed a single time and then will die. most of the time they will have many offspring
what is an iteroparous species
those that breed multiple times in their life.
most of the time they will have fewer offspring
r selective species
species that have a tendency to grow rapidly and have many small offspring at once.
they are more tolerant to areas experiencing stress or disruptions
they will reproduce at an early age one commonly only once before death
k selective species
these speices thend to maintain a population density.
they are larger and slower to develop. in many cases, they will reproduce at older ages and have greater parental investment in their young.
they are iteroparous
how does the principle of allocation impact reporduction?
will influence the number and size of offspring an org can have. if more energy is invested into the report, the org won’t grow as much or have less energy for maintenance
of offspring <-> size of offspring
survival<-> reporduction
what does seed size represent?
it is associated with the plant’s dispersal method.
those that use unassited will have the smallest seeds as a method to increase dispersion. adhesion based seeds are commonly largest
what are the 6 types of dispersal mechanisms
unassisted- no special strucutres
windispersed
ant dispersed
vertebrate dispersed
scatterhoraded
adhesion adapted-
winddisperal seed strucutres
wings or hairs that provide resistance
ant dispersed mechanisms
will have a oil contining structure that is attached to the surface of ants
vertebrate dispersed seed mechanisms
fleshy covering around the seed that attract birds
scatterhoraded mechanisms
seed that have the tendancy to be gathered by and dispersed by mammals
adhesion adapted dispersal mechanisms
seeds with hook or spines to attach to fur
what is the survival/ reproduction trade off
species with a high mortality rate will tend to have a young repod age and have small offspring (quantity investment)
those with a lower mortality will often have a delayed reprod maturity and be able to have fewer offspring which require more parental care (quality investment)
