Evolutionary algorithm chance of reproduction limit

Question

What is supposed to happen:

1. Create a random population of object with attributes containing random integers, all objects will start with a chance of reproduction of 10.(line 16)

2. For all of those objects that have a "number" attribute higher than 4, add 10 to the chance_of_rep attribute pertaining to that object.(line 21)

3. Based off of the "chance_of_rep" attribute, decide whether or not to reproduce offspring. (line 36)

4. Every generation, age each member by 1, if the age is higher than 1, kill that member.(line 47)

What really happens:

The "chance_of_rep" attribute will top off at 50, and will not go any higher than that. Why is this? Besides that, everything else works as it should(at least I believe so, please mention anything that seems awry).

import random as r
import os
import sys
import time
from subprocess import call
#call('color a', shell=True)
class Entity(object):
    def __init__(self, number):
        self.number = number
        self.chance = 10
        self.age = 0
class Fitness(object):
    def __init__(self, population):
        self.population = population

    def StartPopulation(self, pop, entities):
        for x in range(pop):
            entity = Entity(r.randint(3, 5))
            entities.append(entity)

    def FitnessMethod(self, entities):

        for x in entities:
            if x.number >= 5:
                x.chance += 10
            else: 
                x.chance += 0

            if x.chance > 100:
                x.chance = 100

            else: 
                x.chance += 0


    def Reproduce(self,entities):

        for x in entities:
            if r.randint(0, 100) < x.chance:    
                random_children = r.randint(1, 3)
                for a in range(random_children):    
                    entity = Entity(x.number)
                    entity.chance = x.chance
                    entities.append(entity)
                x.age += 1

    def Aging(self, entities):
        for x in entities:
            if x.age >= 2:
                entities.remove(x)          

pop = r.randint(3, 5)
entities = []
Fitness = Fitness(pop)
Fitness.StartPopulation(pop, entities)
for x in entities:
    print x.number, x.chance
print "~~~~~~~~~~~~~\n"
raw_input()


for x in range(30):
    Fitness.FitnessMethod(entities)
    Fitness.Reproduce(entities)
    Fitness.Aging(entities)
    for x in entities:
        print x.number, x.age, x.chance
    print "Generation_Mutation_Complete"
raw_input()

By the way, this isn't homework, it's a personal project.

Answer 1

Well, with no thanks to oli CharlesWorth, I corrected the problem. Here's the corrected code:

import random as r
import os
import sys
import time
from subprocess import call
#call('color a', shell=True)
class Entity(object):
    def __init__(self, number):
        self.number = number
        self.chance = 10
        self.age = 0
class Fitness(object):
    def __init__(self, population):
        self.population = population

    def StartPopulation(self, pop, entities):
        for x in range(pop):
            entity = Entity(r.randint(3, 5))
            entities.append(entity)

    def FitnessMethod(self, entities):

        for x in entities:
            if x.number >= 5:
                x.chance += 10
            else: 
                x.chance += 0

            if x.chance > 100:
                x.chance = 100

            else: 
                x.chance += 0


    def Reproduce(self,entities):
        x = entities[r.randint(0, (len(entities) - 1))]
        if r.randint(0, 100) < x.chance:    
            random_children = r.randint(1, 3)
            for a in range(random_children):    
                entity = Entity(x.number)
                entity.chance = x.chance
                entities.append(entity)
            x.age += 1

    def Aging(self, entities):
        for x in entities:
            if x.age >= 2:
                entities.remove(x)          

pop = r.randint(3, 5)
entities = []
Fitness = Fitness(pop)
Fitness.StartPopulation(pop, entities)
for x in entities:
    print x.number, x.chance
print "~~~~~~~~~~~~~\n"
raw_input()


for x in range(30):
    Fitness.FitnessMethod(entities)
    Fitness.Reproduce(entities)
    Fitness.Aging(entities)
    for x in entities:
        print x.number, x.age, x.chance
    print "Generation_Mutation_Complete"
print "Generation_Mutation_Complete"    
raw_input()