When preparing your presentation, it is wise to bring down the level of information. Unless you are directly talking to other members of your staff, you are going to have to start from the most basic concepts and then go from there without dwelling. After doing so many presentations about animals, I always began with whether the animal was reptile, mammal, bird, or amphibian regardless of the age group. I would then described what characteristics put that animal in that category and then take the animal out and elaborate.
Yes, I worked with animals for five years and yes they were alive. I coordinated an outreach program that took small animals capable of being held and explain animal adaptations and then let the audience interact with the animal by looking up close and touching them. A wise coworker told me to avoid the stumble organize the animal facts from mouth to tail or tail to mouth. I realized over time that the chronological order that was most comfortable for me began with the back, then tail, then feet and belly, lastly head and eyes. Once I put my facts together I hardly ever stumbled for information, I only had to figure out what animal information to leave out otherwise I would spend an hour on each animal and I had five animals and only one hour.
As a speaker, you cannot begin with the complex or even the middle. It wouldn’t make since to bring up the category the animal was in as I was concluding. It would also be senseless to jumble the facts, from feet, to head, to tail, your audience can’t follow you. You must at least recap from the beginning so all audience members are on the same page and you can get a feel for how well the information is grasped before moving on.