Life Science Curriculum K-7
Submitted by: Andy Rotunno
Institution: Azusa Pacific University
Title of Experiment: Survey of Gymnosperms and Angiosperms
Pine seed (fertilized)
Pine cone (male & female)
Leaves (various types)
Blades of grass
Scientific Background of Experiment:
The Plant Kingdom is made up of many different divisions, such as the bryophytes and the seedless vascular plants, gymnosperms and angiosperms. Plants are multicellular and for the most part terrestrial eukaryotes. They are autotrophic which means they can produce their own food or energy. The way that they do this is by a fairly complicated process called photosynthesis. Plants are able to use sunlight for energy to live and reproduce. Because this is true we place them in a group called the producers. There are other groups like the consumers, decomposers and abiotics. Their special ability to make their own energy separates them from the others use producers for their energy and those who breakdown all other organisms.
The following are all the divisions of the plant kingdom:
-Bryophyta ... mosses
-Hepatophyta ... liverworts
-Anthocerophyta ... hornworts
Seedless Vascular Plants
-Psilotophyta ... whisk ferns
-Lycopodophyta ... club mosses
-Pteridophyta ... ferns
-Ginkgophyta ... maidenhair tree
-Cycadophyta ... cycads
-Pinophyta ... conifers
-Gnetophyta ... gnetophytes
-Magnoliophyta ... flowering plants
What we are going to concentrate on is the second half of the divisions. We are going to see how we can determine what different plants are as we walk by them every day. The two kinds of plants we are looking at in this lab are gymnosperms and angiosperms. First we will examine the gymnosperms.
Gymnosperms are much different in comparison to angiosperms. They lack leaves and flowers and instead have needles and cones. The cones are analogous to the flower when comparing gymnosperms and angiosperms. The actual meaning has to do with these two parts of the plants. The word "angiosperm" mean "hidden seed" and the word "gymnosperm" means "naked seed". The cones and flowers are used in reproduction for the plant. In gymnosperms the seeds are found on each wing or piece of the female cone. It is fertilized by pollen from another male cone which enters the female cone. In both gymnosperms and angiosperms the pollen is called the microspore and the seed that houses the ovule is called the megaspore. The fertilized seeds do not stay inside either, they fall off onto the floor exposed and without covering. In angiosperms the ovule is deep with in the ovary at the bottom of the pistil. The pollen is carried or blown to the stigma, which is on top of the pistil. When it lands there pollenation occurs and it travels down to the bottom where the ovule is and fertilizes. When it forms a fruiting body the germinated seeds are found inside the fruit.
We are also going to discuss the differences within flowering plants or angiosperms. The two distinctions we can make are monocot or dicot. Monocots and dicots are classified in a few ways. Below are a few criteria for each:
MONOCOTS- flowering parts in threes and multiples of three. Vascular structures run generally parallel to each other. Leaves are usually slender, long and straight.
Examples: lilies, grasses, reeds, etc.
DICOTS- flowering parts in fours or fives and multiples of four and five. Vascular structures are net-like in pattern. The veins on leaf structure fan out and shoot off at various angles from bigger veins. Leaves are usually more round and short than straight and narrow.
Example: roses, apple trees, daisies.
Gather two or three different types of pine cones. Try to find a few of both male and female cones. Take one of the female cones and point out the small individual segments. Take one or two off of the cone and observe the "naked seed", the megaspore. Then take a male pollen cone and shake some pollen. Compare the size of the pollen to the seed. Then take the fertilized seed and observe the double fertilization. See how the seed is winged so as to be carried by the mind as drops to the ground. Next, look at the pine needles. These needles help to sustain the tree in cold temperatures and to hold in water.
First take the flower and examine that anatomy. Look at the sepals, the petals, the pistil, and the stamen. On the pistil you will find various parts. Fertilization takes place in the pistil at the bottom piece called the ovary which encases the ovule. Examine where the pollen lands on the top of the pistil, the stigma. Pollen comes off of the end of the stamen called the anther. The anther is held up by the filament.
You will need to buy or gather one orange, an apple, and peas that are still in the pod. These are examples of the fruiting body of an angiosperm. Notice how the seeds are surrounded by a mesocarp or fleshy tissue of the fruit. Some plants form fruits at the very end of the flower which is the calyx, like the peach or the orange. Other plants, such as apples, form the fruit at the receptacle which is just before the calyx.
In the angiosperms there are two types of plants, monocots and dicots. Observe the various leaf structures. The leaves that have parallel venation are monocots and the leaves that have a net or branch-like venation are dicots. If you look at the sprouting corn and the sprouting beans you can see differences in the growth of monocots and dicots. Also take two different types and let the student explain the differences of a monocot and dicot and why he or she specified the way they did.
Misc. Helpful Information/ Hints/ Suggestions:
In addition to the plants specimens it would be extremely helpful to take your student on a walk around your house or neighborhood. Let the student explain what he or she sees as they encounter different plants. Be sure to look over other phyla to be able to explain other plants in comparison to angiosperms and gymnosperms. Let the student tell you whether the plant is a angiosperm or gymnosperm. Ask about each plants reproductive mechanisms. If the plant is an angiosperm, challenge the student to explicate the difference between monocots and dicots. Ask about leaf venation and flowering parts. It would also be beneficial to check out some other websites about the plant kingdom.