Busy. Please wait.

show password
Forgot Password?

Don't have an account?  Sign up 

Username is available taken
show password


Make sure to remember your password. If you forget it there is no way for StudyStack to send you a reset link. You would need to create a new account.
We do not share your email address with others. It is only used to allow you to reset your password. For details read our Privacy Policy and Terms of Service.

Already a StudyStack user? Log In

Reset Password
Enter the associated with your account, and we'll email you a link to reset your password.
Don't know
remaining cards
To flip the current card, click it or press the Spacebar key.  To move the current card to one of the three colored boxes, click on the box.  You may also press the UP ARROW key to move the card to the "Know" box, the DOWN ARROW key to move the card to the "Don't know" box, or the RIGHT ARROW key to move the card to the Remaining box.  You may also click on the card displayed in any of the three boxes to bring that card back to the center.

Pass complete!

"Know" box contains:
Time elapsed:
restart all cards
Embed Code - If you would like this activity on your web page, copy the script below and paste it into your web page.

  Normal Size     Small Size show me how

Evolution of sex

Things get weird

sex ratio happens in population where there are many males
size dimorphism female is bigger than their mates.females have better r.s with more food resources and males are always around to provide sperm
adaptive foraging hypothesis sexual cannibalism offers females direct material benefits in terms of food. male meal value is sometimes is higher than his value as a mate.
aggressive spillover hypothesis selection for aggression in other contexts like feeding may to females being more aggressive in other situations. females that are more fierce hunters are bigger and known for cannibalism
mate choice females may cannibalize unwanted males as a method of mate rejection. Works only in some species
sexy son sons that survive. Those males that survive may inseminate 2 or more females and have better r.s. Cannibalism becomes a sexually selected test of mate guilty for females. Better to be inseminated by a male that can evade you. So try to kill him first.
Male conundrum his goal is reproduction so if he mates its worth it. If you are eaten before mating then thats not good. It is ideal to stay alive and mate with more females.
Disable the female some spiders have spurs on their fangs to wedge open the females jaw. Male crab spiders tie the female before mating.spiders drug the female by letting her chew on a horn covered in a powerful drug. sneak up on her- some mantids tip toe
male self sacrifice sexual cannibalism extreme form of male monogamy.provides her with nutrition helps the offspring. male red backed spider somersaults himself in to her mouth. Males that sacrifice have better rs. Copulation is increased she does not re-mate as quickly
Sex reversed cannibalism Males rarely eat their mate. It happens when they are much larger than female. Its opportunistic and not about mate choice.
Apophallation deliberate amputation of the penis
Westermarck effect adults are not sexually attracted to people they grew up with. Domestic proximity desensitizes individuals to sexual attraction regardless of kinship
MHC complex similar genetics leads to major histocompatibility complexes. Attraction is much stronger to those with different MHC complex. Thought to be evolved to maximize heterozygote. Good for red queen.
Incest Taboos no sexual relationship between relatives. 2 reasons one is biological and other is cultural ex alliances. Risk two recessive alleles will come together. Occurs in hermaphrodites when they self fertilize
Created by: karinakll