Figure 7.23 Clownfish Size Hierarchies
Oct 3 2013
Sequence of live events in an organism. (growth/development/reproduction/death) We are
interested in all of these factors. For a human, you go through a period of growth and then you
reproduce. On average, you live to 80. Our perception of life history is biased based on our
experiences. However, many organisms experience very different life histories.
Life history characteristics include: age and size at sexual maturity, amount and timing of
reproduction, survival and mortality rates
Clown Fish Case Study-FINDING NEMO
Clown Fish hang in sea anemones for protection. Anemones sting the predators of clownfish,
but not the clownfish themselves. The fish also benefit the anemone by eating its parasites or
driving its predators away.
Usually 2-6 will hang out in one sea anemone for their entire adult lives. However, it is unlikely
that they are related.
Largest clownfish is female. Next largest is the breeding male. All other fish are immature non
breeders. They are simply biting their time waiting for the others to die off so that they can take
their place. (based on body size) In finding Nemo, his mom died. If this actually happened, his
dad would have turned into a female. If female died, breeding male would take her place and
the next fish in line will become the breeding male.
Hatchlings move out of the anemone, and
juveniles must find a new anemone to inhabit.
The reef is dangerous for them. They grow in
open water and then come back to the reef to
find open spots in anemones. When a juvenile
enters an anemone, they are only able to stay if
there is room.
Why do the Clownfish Maintain the
Clown fish are dependent on survival of being
around anemone. (colorful and slow) They are
easy prey outside of the anemone. If you are small and you try to change things, you get pushed
out of the anemone and get eaten. You see through natural selection that aggressive clownfish
do not end up reproducing.