Plants Alternation of Generations

Ovules

haploid egg cells inside of a flower

Gametophyte example plants

spores, eggs or pollen of pine tree

Haploid cell examples

spores, sperm, egg

Plant in Sexual reproductive phase

will make sperm, pollen or eggs

Alternation of Generations in Mosses and Ferns

1. sexual gametophyte stage and an asexual sporophyte stage is present for both cycles. 2. In the gametophyte (1n), mitosis creates male and female gametes (1n) for sexual reproduction. 3. These gametes combine to make zygotes (2n) that grow into the sporophyte phase (2n) of the plant. 4. In the sporophyte stage, plants create haploid spores (1n) through the process of meiosis . 5. They disperse with wind, water, or in the fur of animals. When they land on fertile ground, they grow into the new gametophytes (1n).

Plant 1n example

1n = 12 for pollen or egg of pine tree

Haploid example plant

1n = 12 pine tree pollen or egg

Haploid example animal

1n = 23 in human egg or sperm

Plant 2n example

2n = 24 for pine tree

Alternation of Generations Gymnosperms

1. The adult sporophyte (2n) creates male and female cones (2n) on separate branches of the same plant. 2. These cones are not the gametophytes they contain the haploid spores . 3. The male and female gametophytes (1n) grow from the haploid spores (1n) hidden inside the cones. The male gametophytes (pollen ) disperse with the wind to the sticky female cones where the female gametophytes are enclosed. 4. A pollen tube grows from the pollen grain, allowing the male gametes to travel to the eggs 5. Once fertilization occurs, a seed (2n) forms that drops to the ground and grows into the sporophyte or adult gymnosperm tree

Moss sporophyte

1. The diploid (2n) sporophyte grows directly from the gametophyte as a capsule stalk 2. A spore capsule forms at the end of the capsule stalk 3.Meiosis creates haploid (1n) spores within the spore capsule 4. Spores disperse and grow into new gametophytes

Sporophyte of Fern

1. The diploid (2n) sporophyte grows from a zygote in ferns. 2. Sporangium form underneath fern fronds. 3. Meiosis creates haploid (1n) spores within the sporangium 4. Spores disperse and grow into new gametophytes

Alternation of Generations Angiosperms

1. The gametophytes (1n) grow directly from the sporophyte (2n) in the form of pollen grains and egg cells. 2. Wind, water, and animals bring the pollen and eggs together. 3. Fertilization takes place inside a flower 4. Eventually produces a 2n seed that can produce an adult plant (sporophyte)

Seedless watermelons

1. The ovules of a melon with 44 chromosomes are pollinated by a melon with 22 chromosomes in its diploid cells. 2. The result is a melon with 33 chromosomes that is incapable of producing seeds

Fertilization in a flower

1. pollen (1n) grain containing two haploid nuclei reaches the pistil, it sticks to the stigma 2. A pollen tube grows through the pistil into the ovary, and then into the ovules (1n). 3. The male gametes (two haploid sperm) join with the female gametes within the ovule. One sperm must fertilize the main egg, the other sperm joins the polar nuclei inside the embryo sac to make the endosperm 4. This creates a diploid zygote or seed (2n).

Animal 2n Example

2n = 46 humans

Seed

2n sporophyte that contains a plant embryo and its endosperm

Gametophyte of Fern

5. The gametophyte grows into a heart-shaped plant in ferns. 6. Mitosis produces flagellated male sperm and female egg cells in the gametophyte. 7. Flagellated sperm combine with female eggs cells (usually in moist areas) to form a diploid (2n) zygote.

Moss gametophytes

5. The gametophyte grows into separate male and female adult plants 6. In mosses, the male gametophyte makes the flagellated sperm and the female gametophyte makes the egg cells 7. Flagellated sperm combine with female eggs cells (usually in moist areas) to form a diploid (2n) zygote.

Haploid cell

A cell with half of the chromosomes, or 1n.

Gametophyte

A plant in its sexual reproduction phase

Sporophyte of Gymnosperm

Adult, diploid (2n) tree

2n

Diploid cells with 2 sets of chromosomes

Pistil

Female part of the flower and holds the female gametophytes

Sporophyte is the dominant stage in which plants?

Ferns, Gymnosperms , and angiosperms

Which plants DO NOT release spores?

Gymnosperms and Angiosperms

Which plants will the gametophyte grow within the sporophyte?

Gymnosperms and Angiosperms

Which plants do not have a flagellated male gamete?

Gymnosperms and angiosperms

Gametophyte of Gymnosperm

Haploid eggs and pollen made by the tree

Pollen

Haploid reproductive cell made by certain plants that contain sperm cells

Is Sporophyte 2n or 1n?

It is 2n or diploid

Vascular tissue

Tissues in plants that transport water and food up and down the plant

Angiosperm example

Maple tree, roses, corn, etc

Sporophyte is NOT dominant in which plants?

Mosses

Which plants release spores?

Mosses and Ferns

Which plants have a flagellated male gametes?

Mosses and ferns

Which plants will the gametophytes NOT grow within the sporophyte?

Mosses and ferns

Mosses

Non-vascular plants that do not produce seeds

Double Fertilization

Occurs in flowering plants when one sperm in the pollen fertilizes the egg and the other sperm in the pollen grain fertilzes the outside making the endosperm

Stamen

Part of flower that produces pollen or male gametophyte

Petals

Part of the flower that attracts pollenators like butterflies

Example of Gymnosperm

Pine tree

Sporophyte example plants

Pine tree is the sporophyte

Sporophyte

Plant asexual reproductive phase.

Haploid or 1n phase of plant reproduction

gametophyte

Endosperm

Substance inside of a seed that provides energy for the embryo plant

Ferns

Vascular plants that do not produce seeds

Gymnosperms

Vascular plants that produce seeds in cones

Angiosperms

Vascular plants with flowers that produce seeds with a seed coat

Germenation

When a seed begins growing and becomes a plant with roots and leaves

Pollenation

When pollen is taken from one flower to another for fertilization

egg

a haploid or 1n gamete in living things for reproduction

Spore

a haploid or 1n gamete of some plants such as mosses or fern

Example of Gymnosperm Sporophyte

adult pine tree

Sporophyte phase of Gymnosperm

adult pine tree

Alternation of generation

cycle between sporophyte and gametophyte generations

Animal n example

n = 23 for sperm and egg for humans

embryo sac

part of the ovule

anther

part of the stamen that contains the pollen

Gametophyte phase of Gymnosperm

pollen and eggs in the male and female cones