I know that there are other suggestions for family tree improvements, and here are links to all of them:
This idea contains all of them and more here in this picture (no I did not make it compatible with my creature creator on purpose *cough cough*):
So starting at the top, we have the static button. For more information, you can view to original link, but the reset button is my idea. When creatures are erased from the family tree, the family tree leaves their space open and with the static feature, this can get annoying for some. The reset button allows for your family tree to reset as if you exited the game and came back so everything is in an orderly fashion.
Next, there are the "P" and "G" buttons. The buttons stand for phenotype and genotype which lets you toggle what you can see. In this picture, the genotype button is deactivated which means you can no longer see the genotype both in and out of the family tree.
Below that, there's a lifespan bar. The lifespan bar tells you exactly what you think it tells you. You can hover over it for the same information you would get from hovering over it outside of the family tree. If the creature is dead like the one above, you will still be able to see their lifespan bar along with any damage they had when they died. You will also either be able to see how many days they have left or their cause of death depending on if they are still alive or not.
The numbers on the left side of the screen are blocks for both the endless family tree idea and the island family tree idea. The blocks can either be automatic and save all creatures for a set number of generations (which can be by island if you choose to do so) or be set up for you to save your current family tree at any time. In the case of the automatic saves, a notification will let you know when you have filled all of your slots and ask you if you want to overwrite your top block for the next slot.
At the bottom of the screen, you will notice two gene filters. The top filter will filter in blue whilst the bottom filter will filter in yellow. You may notice that there are no creatures that are yellow, but there are instead green creatures. This is because the two filters will work together meaning that if a creature has both traits, then the creature will appear green rather than yellow or blue. You may also notice that some creatures are a lighter shade of blue than normal and that the bottom green is also different than the rest. This is because the lighter shade of blue represents creatures who are homozygous for the trait in order to distinguish between heterozygous creatures. The different green reflects this as that is the only creature that is homozygous in both traits.
A more subtle difference is that on the family tree itself is that creatures are outlined in different colors. There are five different colors: black, white, green, yellow, and red. Black represents that the creature is dead. White represents that the creature is alive. Green represents that the creature is compatible based on immunity and is toggleable via the button in the bottom right-hand corner of the tree (when clicked on again, it will turn gray and will not show any green, yellow, or red outlines) (after-thought, maybe clicking on the button again will show yellow and red outlines for one compatible gene and no compatible genes. Let me know if you think this should be all in one or if they should be separated out). Note that the black and white outlines are only present when the gene filter is being used due to there being no way of telling who is alive or dead when it is currently being used. Also note that only creatures of the opposite sex to the selected creature will have green, yellow, and red outlines.
You will also notice a small lifespan bar above each creature as well as three dots to represent gems. The small lifespan bar will appear exactly how it appears in-game currently. The gem dots will change colors according to what they are set to as well.
Finally, I propose some new filters:
There are now three new icons: a creature, a clock, and a DNA icon. The creature will show the ages of creatures. The clock will show how much time a creature has left. (Sorry for the creature and clock icons, I didn't have any ideas for what they should be.) Below I will explain the DNA icon in more detail:
As you can see, it is found under the attributes filter with a different color. The different coloration indicates that it does not show numbers but rather letters. You will see two O's for this creature representing offspring and a "P" for partner. Other letter codes include "F" for father, "M" for mother, "A" for aunt, "U" for uncle, "S" for sibling, "H" for half-sibling, "C" for 1st cousin, and "N" for niece or nephew. Everyone who is not related in these ways will not have a letter and will remain a face. This creature was a wanderer, so she does not have much.