Plant Reproduction

plant reproduction

Standards: 7.LS1.7 Evaluate and communicate evidence that compares and contrasts the advantages and disadvantages of sexual and asexual reproduction.

Day 1

Asexual Reproduction:

Asexual reproduction is reproduction with only one parent.

In this form of reproduction, a single organism or cell makes a copy of itself. The genes of the original and its copy will be the same, except for rare mutations. They are clones.

The main process of asexual reproduction is mitosis. This type of reproduction is common among some single-cell organisms, for example, amoeba. Many plants also reproduce asexually.

Binary fission

A cell splitting and becoming two cells (overview)

Some organisms like bacteria reproduce using binary fission. They split in two, so one bacterium becomes two bacteria. This always leads to daughter cells, and the offspring will be identical to the parent.

Budding

Budding is similar to binary fission, but it is used by plants and some animals, which cannot simply split in half as bacteria can. It is when a small part of a plant or animal breaks off and then, while they are separated from their "mother", they start to grow until both the "parent" and the "offspring" are the same size and both are capable of budding again. This may happen many more times.

Fragmentation/ regeneration

This process occurs when a parent organism breaks into fragments, or pieces, and each fragment develops into a new organism. Starfish, like the one in Figure below, reproduce this way. A new starfish can develop from a single ray, or arm. Starfish, however, are also capable of sexual reproduction.

runners- plants send out shoots or stems to create a new plant

Day 2

Plant reproduction

Plants can reproduce sexually or asexually. Methods such as runners, bulbs, rhizomes are forms of asexual reproduction which creates plants that are exact copies of the parent plant. Plants may produce spores that can into a new organism. Some spores will grow into a new plant that has male and female parts to produce seeds. So, depending on the type of spore it could fall into both categories. Some examples of spore producing organisms are ferns, liverworts, fungi and mold. Plants that create seeds reproduce sexually.

Seedless Reproduction moss

Nonvascular Seedless Plants

Non vascular plants do not have tubes running through them. Moss and liverworts are two examples of this type of plant. There are two stages involved for reproduction. The sporophyte stage of most non vascular plants is so small that it can be easily overlooked These plants produce haploid spores at the end of their sporophyte stage in structures called spore cases. When the spore case breaks open, the spores are released and spread by wind or water and grow into plants that will produce sex cells. The gametophyte stage is when you see green, low-growing masses of the plant. When you see brownish stalks growing up from the tip of the gametophyte plant, you are looking at the sporophyte stage. This part depends on the gametophyte for nutrients and water

On the tip of the stalk is a tiny capsule that contains millions of spores. When the environmental conditions are right, the capsule will open and the spores will either fall to the ground or be carried by wind and new moss gametophytes can grow from each spore.

Non vascular plants can also reproduce by asexual reproduction If a piece of a moss gametophyte plant breaks off, it can grow into a new plant. Liverworts can form small balls of cells on the surface and these can be carried by water and grow into new gametophyte plants if they settle in a damp environment.

Vascular Seedless Plants

Fern Life Cycle Unlike nonvascular seedless plants, the gametophyte of vascular seedless plants is the part that is small and often overlooked

The ferns you see in nature and as house plants are the sporophyte plants They grow from an underground stem called a rhizome. Roots absorb water and nutrients and they make their own food by photosynthesis. Spores are produced in structures on the underside of the fronds called sori

They look like crusty rust-, brown. or dark-colored bumps. If a fern spore land on damp soil, it grow into s small, green, heart-shaped gametophyte plant called a prothallus

It is hard to see because most of them are only 5mm to 6mm in diameter. They contain chlorophyll and absorb water and nutrients from the soil, and make their own food. Ferns can also reproduce asexually.

Rhizomes grow underground and form branches and the new fronds and roots develop from each branch.

Activity 1: Answer the questions from the reading

Study Questions

1. Why are spores important to seedless plants?

2. What is the gametophyte stage of the moss plant? the sporophyte stage?

3. What does the sporophyte stage of the moss plant do?

4. What do spores do when they reach a location?

5. How do liveroworts reproduce asexually?

6. Where are the spores of ferns produced

7. What happens when a fern spore hits the ground?

8. How do ferns reproduce asexually?

Activity 2: Brain Pop: Seedless Plants

Watch the movie and take the quiz.

Activity 3: Go to Study Jams http://studyjams.scholastic.com/studyjams/jams/science/plants/plants-without-seeds.htm watch the slide show and take the quiz.

Activity 4: Go to Study Jams

http://studyjams.scholastic.com/studyjams/jams/science/plants/mosses-and-ferns.htm

Watch the slide show and take the quiz

Day 3

Seed producing plants: Gymnosperms and angiosperms

Gymnosperms

A gymnosperm is a vascular plant that produces seeds lacking an outer fruit. Normally these seeds are contained in cones. There are four groups of gymnosperms: conifers, cycads, ginkgoes and gnetophytes Gymnosperms have male and female cones. The male cones produce sperm, which are contained in pollen grains. Male cones are normally smaller than female cones.The female cones produce eggs, which are contained in ovules. Female cones have a sticky resin that “catches” the pollen released by the male cone. When fertilized, the female cone enlarges and the scales separate. This separation allows the seeds to drop out of the cone and are dispersed by animals, such as chipmunks & squirrels.

Activity 1: Watch the video and answer the questions at the end. https://www.schooltube.com/video/11f8e4557fcd4771b11a/Unit%2011,%20Section%202%20%22Gymnosperms%22

Activity 2: Watch Brain Pop Gymnosperms and take the quiz.

Activity 3. Illustrate the process above but put it in your own words.

Day 4

Angiosperms are the largest group of plants on Earth. There are approximately 270,000 known species alive today. There's probably one nearby right now. Angiosperms include all plants that have flowers and account for approximately 80% of all known living plants.

Angiosperm Characteristics

Angiosperms are able to grow in a variety of habitats. They can grow as trees, shrubs, bushes, herbs, and small flowering plants. Some of the characteristics of angiosperms include:

All angiosperms have flowers at some stage in their life. The flowers serve as the reproductive organs for the plant, providing them a means of exchanging genetic information.
Angiosperms have small pollen grains that spread genetic information from flower to flower. These grains are much smaller than the gametophytes, or reproductive cells, used by non-flowering plants. This small size allows the process of fertilization to occur quicker in the flowers of angiosperms and makes them more efficient at reproducing.
All angiosperms have stamens. Stamens are the reproductive structures found in flowers that produce the pollen grains that carry the male genetic information. There are two parts. The top part is called the anther and the long part is called the filament.
Angiosperms have much smaller female reproductive parts, called the pistil, than non-flowering plants, allowing them to produce seeds more quickly. The top part is the stigma. This is where the pollen is deposited. The style is the tube that leads down to the ovary. The ovary is at the base of the pistil that holds the egg cells otherwise know as ovules.
Angiosperms have carpel that encloses developing seeds that may turn into a fruit.
A great advantage for angiosperms is the production of endosperm. Endosperm is a material that forms after fertilization and serves as a highly nutritional food source for the developing seed and seedling.Examples