Plant Life Cycles Plant life cycles alternate between two cycles: Producing spores and producing gametes A two phase life cycle is called alternation of generations Diploid phase Haploid phase Alternates between PHASE fertilization the two PHASE meiosis The spore producing plant is the mature sporophyte phase h is diploid id Begins with fertilized Spores produced through meiosis The gamete producing plant is the mature gametophyte phase is haploid Begins with ihspore Gametes produced through mitosis fertilization PHASE PHASE meiosis Life cycle phases look different among various plant groups Nonvascular plants have a dominant gametophyte phase Moss gametophytes look like green carpet Moss sporophytes shoot up as stalk like like structures sporophyte (2n) gametophyte (1n) capsule spores (1n) 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 3) Diploid sporophyte will grow from 4) will create and release haploid spores 5) Haploid spores land and grow into new gametophytes 6) The process repeats male male female female female male female male ground
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 3) Diploid sporophyte will grow from 4) will create and release haploid spores 5) Haploid spores land and grow into new gametophytes 6) The process repeats male male female female female male female male ground Plant Life Cycle Comparisons Fern Life Cycle Plant type Dominant? Moss Stalk with cup More familiar, (capsule) at tip, which is where spores are carpet like plant that produces specialized gametes produced Fern More familiar, leafy plant with clusters of spore producing sacs (sori) Haploid plant body (prothallus) is size of a finger nail, produces both male and female parts Conifer More familiar like pine trees, Pollen grains are male produces male and gametophytes female cones that sperm, female produce spores gameotphytes are microscopic s The sporophyte is the dominant phase for seedless vascular plants Fern spores form in sacs, sori, onunderside of mature sporophytes (fronds) A fern gametophyte, or prothallus, produces sperm and s gametophyte (1n)) sporophyte p (2n) rhizoid sori A t f th th ll i i t th A forms on the prothallus, growing into the sporophyte
1) creates and releases haploid spores 2) Haploid spores land in the soil Adult (diploid) 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 5) Diploid sporophyte grows from the sporophyte 6) Fronds uncurls into leaves 7) Cycle repeats Haploid sporescreatedandreleased and released
1) creates and releases haploid spores 2) Haploid spores land in the soil Adult (diploid) 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) Lt Let s zoom back out 5) Diploid sporophyte grows from the 6) Fronds uncurls into leaves 7) Cycle repeats -- Haploid spores created and released ground
Plant Life Cycle y Comparisons p Plant type Moss Stalk with cup at tip, which is where spores are produced More familiar, carpet like plant that produces specialized gametes Fern More familiar 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 Conifer More familiar like pine trees, produces d male l and d female cones that produce spores Pollen grains are male Æ gametophytesæ sperm, female gameotphytes are microscopicæ s Conifer Life Cycle Dominant? The sporophyte is the dominant phase for seed plants 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 4) Pollen tube grows from the male spore 5) Two nuclei transfer into female spore one fertilizes the 6) Diploid embryo develops (sporophyte stage restarts)
7) After seeds harden, the cone reopens and the seeds are released 8) Seed will land 9) Seedling grows into (sporophyte) the cycle repeats 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 4) Pollen tube grows from the male spore 5) Two nuclei transfer into female spore one fertilizes the 6) Diploid embryo develops (sporophyte stage restarts)
7) After seeds harden, the cone reopens and the seeds are released 8) Seed will land 9) Seedling grows into (sporophyte) the cycle repeats Plant Life Cycle Comparisons Plant type Dominant? Moss Fern Conifer (Gymnosperm) Stalk with cup at tip, which is where spores are produced More familiar, leafy plant with clusters of spore producing sacs (sori) More familiar like pine trees, produces male and female cones that produce spores More familiar, carpetlike plant that produces specialized gametes Haploid plant body is size of a finger nail, produces both male and female parts Male gametophytes are pollen grains sperm Female gametophytes are microscopic s Angiosperm Life Cycle Flowers contain reproductive organs prcted by specialized leaves Sepals and petals are modified leaves Sepals are outermost layer that prcts developing flower Petals can help to attract animal pollinators stamen d l i fl filament anther A stamen is the male structure of the flower anther produces pollen grains carpel filament supports the anther stigma style ovary The innermost layer of a flower is the female carpel stigma is sticky tip style is tube leading from stigma to ovary petal ovary produces female gametophyte sepal
Flowering plants can be pollinated by wind oranimals 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 din anthers by meiosis each spore divides by mitosis to form two haploid cells two cells form a Pollen grain single pollen grain Stamen Filament Anther One female gametophyte can form in each ovule of a flower s ovary 1 Pollen stick to animal or released into wind Many cells can be made in the ovule One cell becomes the One cell becomes 2 polar nuclei The rest die Polar nuclei (2n) 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 4 Each ovule becomes a seed Endosperm provides food supply for embryo endosperm seed coat Double Fertilization sperm polar nuclei The surrounding ovary grows into a fruit embryo ovule 1 sperm fuse with the polar nuclei = triploid (3n) endosperm 1 sperm fuse with the = 5 Seeds get dispersed 6 Seed germinates, and the cycle starts over Plant Life Cycle Comparisons Plant type Dominant? Moss Fern Conifer (Gymnosperm) Stalk with cup at tip, which is where spores are produced More familiar, leafy plant with clusters of spore producing sacs (sori) More familiar, carpet like plant that produces specialized gametes Haploid plant body is size of a finger nail, produces both male and female parts More familiar like pine Male gametophytes are trees, produces male and pollen grains sperm female cones that Female gametophytes are produce spores microscopic s 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 + 2 polar