Kelly - Scavenger Hunt #7

These pictures are from Moody Gardens on Galveston Island, Texas.

1.Homologous Structures

 This is a picture of a seal skeleton. The flippers of the seal and arms of humans are considered homologous structures. They are used differently but they are supposed to be from a common ancestor.

2. Mating Behavior

These are Potbelly Seahorses. The female is the larger and brighter colored one, which helps to attract the male. Once they have found a mate they are monogamous, which is very odd for fish. Seahorses mate during a full moon. They begin with a courting process where they curl the ends of their tales to each other and swim together. This can last for days. During courting the male will open and close a pouch where the female will eventually deposit hundreds of eggs. The male then fertilizes them and they grow for 2 to 5 weeks. The male gives birth but he doesn’t take care of the baby seahorses, they are on their own.

3. Asexual Reproduction

Organisms that reproduce asexually reproduce by mitosis so their offspring are genetically identical to the parent.  Some plants and animals can reproduce asexually.

This picture is a sea star, sometimes called a starfish. They belong to the phylum Echinodermata which means “spiny skin.” Sea stars can be found in every ocean and they can live in both the intertidal zone and in deep water.

There are male and female sea stars but they look the same from the outside. Sea stars usually reproduce sexually but asexual reproduction can also take place. If they reproduce asexually it is by regeneration. If a sea star is split, it can re-grow another entire organism as long as part of the central disk is left.

 

4. Littoral zone organism

The area where the sea and land meet is the littoral zone, also called the intertidal zone. During high tide this area is covered by water and at low tide it is open to the air.  Some of these areas are muddy, some are sandy and some are covered with rocks.

Crabs, sea stars, sea urchins, mussels and sea anemones can be found in littoral zones. The organism in this picture is a sea anemone. This one is about three inches across but some grow up to three feet. They attach themselves to surfaces like rocks, coral or even a shell, but they can move very slowly and sometimes they float in the water. They feed on small fish and shrimp. Their mouth is at the top and is surrounded by tentacles they use to sting their prey and move it into their mouth.  If they are threatened they will pull their tentacles in and form a ball.

Sea anemones and hermit crabs sometimes have a relationship that benefits both (mutualism). The anemone attaches to the hermit crab’s shell which allows the anemone to get a fresh supply of food. The crab benefits because the anemone’s stinging tentacles protect it from predators.

And of course, there is also the relationship between Nemo and an anemone! Clown fish live in anemones, safe from predators and they help keep the anemone clean.

5. Homeostasis

Homeostasis is when an organism is able to keep its entire internal systems stable even if their environment changes.

The penguins in this photo are King Penguins and Rockhopper Penguins. The Rockhopper penguins are smaller and have the yellow feathers on their head.

An example of homeostasis is an organism’s ability to keep their body temperature stable. Penguins have adaptations that control their heat loss by controlling the amount of warm blood that goes to different places in their bodies, for example, their wings and feet. These parts are not well insulated so they can have a large amount of heat loss.  They will keep just enough blood flowing so their feet and wings can’t freeze. Sometimes, if they are too warm, they will also increase blood flow to their feet and wings to allow heat to escape.

Feathers also help penguins keep their temperatures stable.  When sitting in a cold wind they will cover their feet with their feathers and a layer of fat underneath the feathers. In the cold they can puff their feathers out to trap air which acts as insulation. If they are too hot they can puff their feathers even more and the warm air can escape.

Another adaptation penguins have is called countercurrent blood flow. They have an artery that carries the warm blood to their wings and feet. Next to it are two veins that carry the cooler blood back to their heart. When the cool blood flows next to the warmer artery it is able to absorb some of the heat before it goes to the main body of the penguin. This keeps the core of their body from cooling too much.