Populations interact by:

1. Cooperate

1.1. Make mixed babies (rare)

1.2. Eat together

1.3. Working together

1.3.1. Protect each other

1.3.2. Make shelter (a home)

1.4. Make something for each other

1.4.1. Oxygen

1.4.2. Carbon Dioxide

1.4.3. Nectar

2. Competition

2.1. Eating each other

2.1.1. Hunt

2.1.2. Chase

2.2. Protect themselves

2.2.1. Stay away

2.2.2. Make noise

2.3. Fight

2.3.1. for space

2.3.2. over the same food