Reproductive Strategies Summary

Reproduction
A where
biological process a
living organism produces offspring
'


.




Genes transferred essential for survival i. evolution
-



are =
.




*
Reproductive success =
number of viable offspring an individual produces .




*
Reproductive strategy depends on how well an organism utilises energy to produce i. care for
offspring .




i. r -


strategy
More energy to produce MANY offspring
9




Little energy / time in
parental care
•


.




'




Many offspring die before adulthood but sufficient numbers survive to reproduce .




K
2
strategy
-

.




Fewer offspring produced
•




•


More in parental care
energy
Offspring better chance of survival
•

=




survivorship curve

concave curve

R strategy
-
-

is
1000 -




•
§
5
-
s Convex curve
n 100 -




* K strategy
-
-




§
E 10 -




-

z
Straight line

Steady survivorship
'




150
0
100

Eg small birds or squirrels .




% of maximum lifespan

, Courtship behavioural patterns that lead to mating and then offspring .




Purposes : I . Ensures both sexes are ready for mating

2. Saves
energy
=
help identify mates from same species (avoids unsuccessful mating )
Choose suitable mate [ males T chance of survival)
3. that are larger & stronger =
offspring

* Visual stimuli
E.g. Peacocks tail feathers
'


Fireflies flash specific light pattern .




* sound stimuli
E.
g Frogs and birds


* chemical stimuli
Females secrete pheromones :
signals they are sexually mature

E.g. Moths, dogs, female lions



*
Physical movement
Scorpions dance
•




Male tortoises t head
message
'




Male does aerobatics
eagle
'




Male weaver birds nests
•


make



⑨
• Environmental changes can affect mating .




'

Mammals = short mating season : births occur at most favourable times .