Natural Selection Flashcards
Natural selection
2
- certain heritable traits make more offspring
- changes genetic pop over time
Requirements natural selection
3
1) variation in pop
2) trait heritable
3) variation in trait associated with diff fitness
Adaptations
3
- heritable traits that increase ability survive/ reproduce compared without trait
- natural selection only mech result increase f adaptive traits overtime
- start mutation, increase f pop with natural selection
Is natural selection random?
2
No
- individuals survive/reproduce not random (contrast genetic drift)
- alleles help survive more likely to be common
Is natural selection perfect?
No (good enough)
Do individuals evolve with natural selection?
No
- individuals don’t evolve, only more/less successful reproducing
- only pop evolve
What is directional natural selection?
3
- favors individuals at extremes at one end of spectrum
- selects against other phenotype
- reduces diversity
What is stabilizing in natural selection?
3
- Favor intermediate
- against extremes
- variation reduced
What is distributive natural selection?
- favor both extremes
What is sexual selection?
3
- non- random mating
- females (less males ) determines which alleles get passed on (opposed environment)
- individuals with certain inherited traits more likely reproduce and pass on alleles
Ecological selection
- environmental determines which alleles get passed on
2 mechs for sexual selection
- competition mates ( intrasexual)
- mate choice (intersexual)
Intrasexual selection
4
- males competes against each other ( can be costly )
- seed signals ability to competes /provide
- sneaky males
- invest heavily in sperm
Intersexual selection
- males fitness limited by access female , females must be picky though
- if mother invest more offspring , more selective
Female vs make fitness
Female: fitness of babies
Males: how much they procreate
2 hypothesis for why females choose certain males
1) direct benefit (provide resources female)
2) indétectable benefit ( gold alleles/ gene)
What is a direct benefits for females being picky
- male parental care (give gifts (get resources))
What are indirect the benefits for female being picky?
- phenotypic indicators good genes / increase fitness
- build elaborate structures ( have skills/ energy)
Is natural selection and evolution the same?
No
Natural selection is the process
If change f phenotype can assume natural selection occurred?
No
Can be due environment
Who has better fitness
A) 10 babies dies in a year
B) 8 babies lives 8 years
A
Is natural selection goal oriented ?
No
Does natural selection produce perfection?
No
Is natural selection random?
No
