Tagged Questions
0
votes
0answers
32 views
Why aren't antheridia and archegonia touching?
Antheridia and archegonia are the two male and female gametangia, respectively, and they are found in bryophytes. To cause fertilization, usually a thin film of water must be present for the sperm ...
4
votes
1answer
106 views
Which sex has higher variance of reproductive rate in modern societies - male or females?
Who has a more varied reproduction rate in modern western societies - men or women? The average rate is the same of course, but I wonder which sex have higher variance - higher variance means that ...
3
votes
1answer
53 views
Would ovoviparous to viviparous mutation have been gradual? How would that work?
It seems unlikely that an ovoviparous ancestor of mammals long ago could have had a viviparous offspring in a sharp one-generation dividing line, but what would be the gradual steps between egg birth ...
8
votes
2answers
804 views
Why are not all species hermaphrodites?
If a hermaphrodite animal (like slug, snail, etc) finds a partner they can mate immediately.
If another animal with "normal" reproduction (lets say a mouse) finds a partner they can only mate if they ...
4
votes
1answer
107 views
What evolutionary pressures pushed Galápagos tortoises to mature so slowly and live so long?
I read that they take up to 40 years (in the wild) to reach the age of reproduction and are thought to live over 100 years, with one in captivity reaching over 170 years.
Can someone explain in ...
3
votes
1answer
145 views
4
votes
1answer
54 views
Productive turnover and generations in the fruit fly
I was reading about the Lenski experiments on the evolution of E. coli bacterium and Dr. Elders's experiments on the evolution of the guppy.
These two experiments absolutely fascinated me, and seemed ...
1
vote
1answer
212 views
What animals stop other members of their species from mating and why?
(In particular primates)
I know chimps do. Powerful alpha males chimp would beat up omega males that they caught mating.
I know gorillas do. Powerful alpha males gorillas would beat up omega males ...
