Plant Life Cycles

Meiosis Review Cell starts diploid –E–Ex: Human = 46 chromosomes Cell divides twice to create 4 cells End result: Haploid cells –E–Ex: Human = 23 chromosomes Cells created: Sperm, egg, pollen

Alternation of generations (In general) Diploid zygote created Diploid zygote grows into a diploid sporophyte Haploid spores created by meiosis Haploid spores grow into haploid gametophytes –M–Male gametophyte creates haploid sperm –F–Female gametophyte creates haploid egg Sperm and egg fuse to make a diploid zygote Cycle restarts fertilization meiosis SPOROPHYTE PHASE GAMETOPHYTE PHASE

Moss Life Cycle

gametophyte 1)Moss gametophytes grow near the ground (haploid stage) 2) Through water, sperm from the male gametophyte will swim to the female gametophyte to create a diploid zygote 3) Diploid sporophyte will grow from zygote 4) Sporophyte will create and release haploid spores..... sporophyte egg male female zyg ote

5) Haploid spores land and grow into new gametophytes..... groundgametophyte 6) The process repeats

..... sporophyte egg male female zyg ote

5) Haploid spores land and grow into new gametophytes..... groundgametophyte 6) The process repeats

Fern Life Cycle

Adult Sporophyte (diploid).... 1) Sporophyte creates and releases haploid spores ground

.... 2) Haploid spores land in the soil

ground 3) From the haploid spores, gametophyte grows in the soil Let’s zoom in

4) Sperm swim through water from the male parts (antheridium) to the female parts (archegonia) Let’s zoom back out egg zyg ote

ground 5) Diploid sporophyte grows from the zygote sporophyte

6) Fronds uncurls into leaves. ground 7) Cycle repeats -- Haploid spores created and released....

Adult Sporophyte (diploid).... 1) Sporophyte creates and releases haploid spores ground

.... 2) Haploid spores land in the soil

ground 3) From the haploid spores, gametophyte grows in the soil Let’s zoom in

4) Sperm swim through water from the male parts (antheridium) to the female parts (archegonia) Let’s zoom back out egg zyg ote

ground 5) Diploid sporophyte grows from the zygote sporophyte

6) Fronds uncurls into leaves. ground 7) Cycle repeats -- Haploid spores created and released....

Plant Life Cycle Comparisons Plant typeSporophyteGametophyteDominant? MossStalk with cup at tip, which is where spores are produced. More familiar, carpet-like plant that produces specialized gametes GAMETOPHYTE FernMore familiar, leafy plant with clusters of spore producing sacs (sori) Haploid plant body is size of a finger nail, produces both male and female parts SPOROPHYTE ConiferMore familiar- like pine trees, produces male and female cones that produce spores Pollen grains are male gametophytes  sperm, female gameotphytes are microscopic  eggs SPOROPHYTE

Conifer Life Cycle

1) Male and female seed cones grow in adult sporophytes

2) Pollen grains released from the male seed cones -- Pollen is the male gametophyte Let’s zoom into the female seed cone

3) Pollen grain sticks to the female ovule 5) Two nuclei transfer into female spore - one fertilizes the egg 4) Pollen tube grows from the male spore 6) Diploid embryo develops (sporophyte stage restarts)

7) After seeds harden, the cone reopens and the seeds are released

8) Seed will land ground

9) Seedling grows into (sporophyte)…the cycle repeats ground

1) Male and female seed cones grow in adult sporophytes

2) Pollen grains released from the male seed cones -- Pollen is the male gametophyte Let’s zoom into the female seed cone

3) Pollen grain sticks to the female ovule 5) Two nuclei transfer into female spore - one fertilizes the egg 4) Pollen tube grows from the male spore 6) Diploid embryo develops (sporophyte stage restarts)

7) After seeds harden, the cone reopens and the seeds are released

8) Seed will land ground

9) Seedling grows into (sporophyte)…the cycle repeats ground

Plant Life Cycle Comparisons Plant typeSporophyteGametophyteDominant? MossStalk with cup at tip, which is where spores are produced. More familiar, carpet- like plant that produces specialized gametes GAMETOPHYTE FernMore familiar, leafy plant with clusters of spore producing sacs (sori) Haploid plant body is size of a finger nail, produces both male and female parts SPOROPHYTE Conifer (Gymnosperm) More familiar- like pine trees, produces male and female cones that produce spores Male gametophytes are pollen grains  sperm Female gametophytes are microscopic  eggs SPOROPHYTE

Angiosperm Life Cycle

Flowers contain reproductive organs protected by specialized leaves carpel style stigma ovary stamen filamentanther petal sepal Sepals and petals are modified leaves. Sepals are outermost layer that protects developing flower Petals can help to attract animal pollinators A stamen is the male structure of the flower anther produces pollen grains filament supports the anther The innermost layer of a flower is the female carpel. stigma is sticky tip style is tube leading from stigma to ovary ovary produces female gametophyte

Flowering plants can be pollinated by wind or animals Wind pollinated flowers have small flowers and large amounts of pollen. Animal pollinated flowers have larger flowers and less pollen. many flowering plants pollinated by animal pollinators –pollination occurs as animal feeds from flower to flower –animal pollination more efficient than wind pollination

Fertilization takes place within the flower Male gametophytes, or pollen grains, are produced in the anthers. –male spores produced in anthers by meiosis –each spore divides by mitosis to form two haploid cells –two cells form a single pollen grain Pollen grain Anther Stamen Filament

Many cells can be made in the ovule One cell becomes the egg One cell becomes 2 polar nuclei The rest die Polar nuclei (2n) One female gametophyte can form in each ovule of a flower’s ovary

1. Pollen stick to animal or released into wind.

2. Animal finds a new flower to feed on and pollen grains land on the stigma (pollination)

.. 3. Pollen tube grows and 2 nuclei transfer into the ovule Let’s zoom in…

3. Flowering plants go through the process of double fertilization. female gametophyte ovule egg sperm polar nuclei 1 sperm fuse with the polar nuclei = triploid (3n) endosperm 1 sperm fuse with the egg = zygote Double Fertilization

endosperm seed coat embryo Endosperm provides food supply for embryo 4. Each ovule becomes a seed. The surrounding ovary grows into a fruit.

5. Seeds get dispersed 6. Seed germinates, and the cycle starts over ground

Plant Life Cycle Comparisons Plant typeSporophyteGametophyteDominant? MossStalk with cup at tip, which is where spores are produced. More familiar, carpet-like plant that produces specialized gametes GAMETOPHYTE FernMore familiar, leafy plant with clusters of spore producing sacs (sori) Haploid plant body is size of a finger nail, produces both male and female parts SPOROPHYTE Conifer (Gymnosperm) More familiar - like pine trees, produces male and female cones that produce spores Male gametophytes are pollen grains  sperm Female gametophytes are microscopic  eggs SPOROPHYTE Flowers (Angiosperm) More familiar - apple tree, peach tree, zucchini, berries, etc. Contain flowers that produce male and female spores Pollen grains are male gametophytes  2 haploid cells = pollen tube + sperm Female gametophyte in ovule  egg + 2 polar nuclei SPOROPHYTE