CH5 Reproduction in Plants

diploid phase

(2n = two copies of each chromosome) = sporophyte -diploid: A cell containing two sets of chromosomes (2n), one set inherited from each parent.

Haploid

(genetics) an organism or cell having only one complete set of chromosomes

Explain the cycle of a moss

- The leafy green gametophyte (lower right) is the haploid generation that produces sperm and eggs. 1. The leafy green gametophyte has two specialized chambers. ---Antheridium: -produces sperm (w/ flagella to swim) ----Archegonium: -produces the egg 2. The sperm must swim through a film of water to the egg. -the sperm follows concentration gradients to swim through water on the soil in substrate or water from leafy part of the gametophyte to another gametophyte nearby 3. it follows concentration gradience to an archegonia (chamber where the egg is at) where there is an egg ready to be fertilized. ALSO Archegonia has one single egg cell and opens when egg cell is mature -The cells of archegonia that are surrounding egg cell releases chemicals for the sperm to track the egg. 4. Multiple sperms swim over and one fertilizes egg and we get a diploid zygote. (diploid zygote is part of the sporophyte generation) 5. Zygote begins development inside and is protected by the Archegonium. It late grows out of the gametophyte. 6. Sporophyte is nutritionally dependent on the gametophyte (they don't do photosynthesis/ have own structures to get water and nutrients)

how long does it take for a pine cone to develop?

- a long time -about 2-3 yrs (from fertilization until the point where the seeds are ready to be released)

what are some exceptions to the sperm swimming to its own archegonium?

- selaginella (a genus of vascular plants) that has megaspores that develop into egg producing gametophytes (mega gametophytes) -these mega gametophytes are very large *this proves that not all species of seedless tracheophytes are homosporous but majority are!

What is the alternation of generations in plants like?

-Cells in sporangia undergo meiosis to produce haploid, unicellular spores. -Spores develop into a multicellular haploid plant—the gametophyte—by mitosis. -Gametophytes produce haploid gametes by mitosis. -Fusion of gametes (syngamy or fertilization) results in a diploid zygote. -The zygote develops into the multicellular sporophyte.

what is the alternation of generation in plants?

-Cells in sporangia undergo meiosis to produce haploid, unicellular spores. -Spores develop into a multicellular haploid plant—the gametophyte—by mitosis. -Gametophytes produce haploid gametes by mitosis. -Fusion of gametes (syngamy or fertilization) results in a diploid zygote. -The zygote develops into the multicellular sporophyte.

What are advantages of sexual reproduction?

-Diverse offspring -adaptability -can live in different environments (enviroments that change)

what is the process of pollen grain fertilization process

-Pollen grains are carried through the air (by wind or by animals) to the ovules (often of another plant) - once it arrives, the polengrain is drawn into the micropyle (its at the extention of the ovule that has a moist spot where the pollen attaches) - it then develops the pollen tube, which penetrates the food -storage tissues of the megagametophyte & extends towards the egg. -The sperm cells are released and are drawn toward the egg (or swim in ginkgo & cycads)

what is interesting about the Juniperus cone seed?

-Some cones, such as in Juniperus, can be fleshy, and resemble fruits of angiosperms, but these are still cones --most cones are hard and woody but this one isn't - they just have different scale structures. These have adapted for animal dispersal. Such adaptation are relatively recent in the conifers.

what is the difference between asexual reproduction and sexual reproduction?

-asexual reproduction results in no diversity between the generations.

how do Miracle leaf reproduce?

-asexually -the new plantlets grow from leaves. -these leaves can be used for asexual reproduction. Mosses can asexually reproduce from gemmae (embryo like bodies that separate from the parent)

why is the receptacle important?

-bc the structure of the receptacle and if the ovary is above, deep in it, etc are key characteristics for identifying plants in the diachotimous key. (osea where the ovary is relative to where the receptacle is important.)

why is it important that the female cone has tough closing scales?

-because it protects the ovule. -the ovule takes a long time to develop (2-3 yrs) so, it is important to protect it.

What are the types of reproduction in plants?

-can be asexual and sexual

how is the uniqueness of pollen grain help?

-can be used to identify plant material in geologic strata and tell us about plants that existed before, in archeological remains or in forensic elements. (to tell if bodies have been moved)

In the fern life cycle, the ______ generation is dominant.

-diploid sporophyte -sporophyte is dominant

Heterospory

-found in only aquatic seedless vascular plants

Pollen

-it is a spore with a highly reduced gametophyte within -the tiny granules that contain the male gametophyte of seed plants

what is the difference between male and female cones? what does each do?

-male: pollen is produced here female: -it is where the ovule is at.

bryophytes

-nonvascular plants (mosses are bryophytes) -they are gametophyte dominant -so, the haploid gametophyte is the most prominent genetation

what happens to the pines where their cones open?

-seed dispersal -they get released and fly down like helicoters -help disperse away from original plant.

self-fertilization is __(asexual/sexual)__ reproduction

-sexual reproduction

on a fronds of a fern there are _____ which are clusters of ___ that produce _____

-sori;sporangia;spores

majority of conifers (female) have what type of outside?

-strong woody cones

what is the difference between earlier plants and megaspore?

-the megaspore does not have a protective covering or get dispersed - instead it develops into the megagametophyte within the ovule, which remains attached to the parent plant until it matures into a seed.

what happens when the pollen grain lands on a different individual (of the same species) and they are unable to self?

-the pollen grain lands on the stigma and it will germinate. -the pollen tube will grow down the carpal, through the stile, to the chambers where the ovules are at.

sporangium

-the sporangium is diploid but inside its capsule meiosis it is occuring. This creates haploid spores. -when capsule opens, they are back to the gametophyte generation -the spores will land in good habitat and grow. -this would create a haploid gametophyte.

Moss laternation of generations

-they are

What are pollengrains?

-they are Smaller and lighter than the microspores of Selaginella -pollengrains get dispersed in the air so their size and weight helps them be better adapted for dispersal by wind (or in some cases animals)

what is particular about the spores in ferns?

-they are all homospore (they all have one size) -

What is the Sori on ferns?

-they are groups of sporangia, which contain spores -they are found in the underside of fern blades

what are the sepals?

-they are outermost whorl part of the flower that are often green.

carpels

-they have ovum baring chambers inside -they have a stile that hold a stigma at the top

what is the stalk?

-where the whole flowering structure is starts at -petistle is the name of that stalk

How do mosses asexually reproduce?

-with the help from gemmae

ovules in gymnosperms

-young ovule is bound by a single integument (outer covering) -Interior of the ovule is technically a megasporangium, but it only produces a single megaspore -Meiosis occurs in a spore mother cell --Meioisis produces 4 haploid cells, but 3 of them disintegrate. So, the last one is the one that is fertilized.

The leafy green gametophyte has specialized chambers. What are they? What is their function?

1. Antheridium: -produces sperm (w/ flagella to swim) 2. Archegonium: -produces the egg -it has one single egg cell and opens when egg cell is mature -cells of arch. surrounding egg cell releases chemicals to for the sperm to track the egg.

Fern life cycle

1. The Haploid spores are formed in sporangia located on the underside of certain leaves 2. They are dispersed by the wind to germinate on the moist forest floor into inconspicuous haploid gametophyte plants

how do Ginger asexually reproduce?

1. ginger also produces new plants from old flowers 2. They asexually reproduce from rhizomes

Pollen grain consist of two functional cells. What are these functions?

1. one forms the pollen tube 2. Will divide through mitosis to form two sperm cells (only one would fertilize cells)

True seeds contain:

1.An embryo 2.Stored food for that embryo 3.Protective seed coat (integument)

alternation of generations

A life cycle in which there is both a multicellular diploid form, the sporophyte, and a multicellular haploid form, the gametophyte; characteristic of plants and some algae.

megaspores

A spore from a heterosporous plant species. -this spore germinates into a female gametophyte, which produces egg cells.

Sporopollenin: a. strengthens the outer wall of the spore b provides a chemical signal that directs the sperm to swim to an egg c. covers the outside if the sporangium to prevent water loss.

A. strenghtens the outer wall of the spore

compare the spores of ferns and gymnosperms/ angiosperms

Ferns: homospore Angiosperm and gymnosperm: -hererospore

what is the difference between protist vs animal alternation of generations?

IN PROTIST: -the haploid gametophyte is where the organisms spends most if its time - the zygote is the fleeting unit (not really an alternation of generation bc the zygote doesn't go through mitosis and grows into a bigger organism) --------- ANIMAL: -they don't have a period of time where there is a gametophyte. -gametes come together and form the zygote. -------- BOTH: -they both give you sexual reproduction aka gives you biological diversity. BUT, doesnt givee you alternation of generations.

What are the advantages of asexual reproduction?

Identical offspring, no special cells required, speedy process, lots of offspring, don't need a mate -it is good for a consistent environment (don't need to adapt to harsh stuff) - good for rapid reproduction (

Meiosis moss life cycle

Meiosis -produce haploid spores inside the capsule

in ovules of gymnospers, where does meiosis occur?

Meiosis occurs in a spore mother cell --Meioisis produces 4 haploid cells, but 3 of them disintegrate. So, the last one is the one that is fertilized.

does the sperm cells of gymnosperms and angiosperms have a flagella?

No. More advanced plants (conifers & angiosperms) have non-motile sperm, basically naked nuclei

what stimulates fruit development?

Pollination stimulates fruit development

what are the differences between ancestral algal spores and today bryophyte spores?

SIMILAR: -sporophytes allow for dispersal over long distances. *angal ancestors do this also DIFFERENCES: Zoospores/angal ancestors: -The zoospores of Coleochaete could swim to new areas bc they are flagellate Spores of bryophytes: - are not flagellated. ----this makes them be much smaller. -sporangia also makes more spores though meiosis --spores are incased in a hard wall that is strengthen by sporopollenin Bryophyte spores are mostly disperesed by wind -this is why sporangea are adapted to be above the leafy gametophytes for them to be more exposed.

how do sporophytes get water and nutrients?

Sporophyte is nutritionally dependent on the gametophyte -they don't to photosynthesis or have mechanisms in their body that help them het these water and nutrients.

stamen

Stamen: Typically - consist of 4 elongate pollen sacs (microsporangia that produce the microgametophytes that lead to pollen grains that ) joined into a common structure called an anther. Anther is elevated on filament (varying length often result of co-evolution with pollinators). Pollen varies(unique to species) and can be used to identify plant material in geologic strata, archeological remains or forensic evidence.

where is the female structure of a flower located?

The pistil is a plant's female part. It generally is shaped like a bowling pin and is located in the flower's center. It consists of a stigma, style and ovary.

what tells if the sporophyte would be dependent or independent on the gametophyte?

The sporophyte depends on which plant group it is.

gametophyte

The stage in the life cycle of a plant in which the plant produces gametes, or sex cells.

what is a spore?

Tiny, waterproof reproductive cell that can grow into a new organism if conditions are right, otherwise it will remain dormant -in a plant exhibiting alternation of generations, a spore is a haploid reproductive cell which gives rise to a gametophyte.

what is the purpose of the petals?

To attract pollinators (bees, hummingbirds, etc)

What is sporopollenin?

a layer of durable polymer that prevents exposed zygotes from drying out

Sexual reproduction would be selected for by a _____ environment. a. heterogeneous b. homogeneous c. stable

a. heterogeneous

where is the male part of the flower located?

at the stamen. (the filament and the anther)

mosses are __ and they are ____ dominant

bryophytes; gametophyte dominant

which of the following is an evolutionary trend in land plants? a. reduction in the sporophyte b. reduction in the gametophyte c. nutritional dependence in the sporophyte d. dominant gametophyte

c)

ovules are in the ____ while pollen is produced in the ____

carpel; stamen

What is the sporophyte generation?

diploid generation, makes monoploid spores by meiosis, asexual generation

where do pollengrains evolve from?

evolved from microspores.

True or False -In ferns, the gametophyte is dependent on the sporophyte

false -in ferns, the gametophyte is independent and dominant. *the gametophyte isn't longlasting.

true or false all conifers have hard, scale like cones

false junipers are different

Angiosperms (flowering plants)

flowering plants

What are angiosperms?

flowering plants

Moss life cycle: Germination produces ___

haploid gametophyde

Ferns have a single sized spore that produces a bisexual gametophyte (produces both antheridia and archegonia). This is called:

homospory

the parts of the flower are all connected where?

in a connected platform called the receptacle.

what is unique about the ovules in angiosperms and in gymnosperms?

in angiosperms, the pollen grains don't enter the ovules as they do in gymnosperms.. they don't get suck on the micropile like in gymnosperms. -they germinate on the stigmas

how are Selaginella spores dispersed?

in the water

heterosporous plants produce what two types of spores?

megaspores and microspores

sperm and egg are produced through ______

mitosis -mitosis occurs wherever there is new cells being produced (even if they are being differentiated into gametes.. it is till happening through mistosis)

does protist go through a alternation of generation?

no bc the zygote is the fleeting unit (not really an alternation of generation bc the zygote doesn't go through mitosis and grows into a bigger organism). so, no.

Ovule evolution:

ovules evolved as ancient megasporangia that were surrounded by leaf segments -these leaf segments later fused and provided only a small point of entry for entry of sperm cells.

What are gymnosperms?

plants that produce seeds without flowers (conifers and cycads)

microsporangia

produce microspores that give rise to male gametophytes osea they that produce the microgametophytes that lead to pollen grains (male) that can deliver the sperm to the stigma of another flower.

What are gemmae?

small multicellular reproductive structures that help liverworts (like mosses) reproduce asexually

what does meoisis do?

takes a diploid cell and produces 4 haploid cells

The sepals and the petals together are called

tepals

Early land plants were distinguish by their algal ancestors by what?

the evolution of distinctive multicellular chambers of the sperm and egg in the gametophytes bryophytes

the male stamen is made up of what two structures?

the filament and the anther

anther:

the part of a stamen that contains the pollen. -made up of 4 pollen sacs -the anther is on the filament.

what is the purpose of the juniperus having a fleshy cone?

to attach to animals and do dispersal like that -may help them get scattered more areas.

true or false a typical flower (most of them but not all) have male and female structures

true

true or false pollen grains are unique and varies. each pollen grain is as different as a fingerprint for us.

true

Bryophyte spores are mostly dispersed by ______

wind -this is why sporangia are adapted to be above the leafy gametophytes for them to be more exposed.

did the sperm cells of gymnosperms (ex: cycads and ginkgo) actually had a flagella?

yes in past lineages they did. -they never swim but they moved down the pollen tube could never swim in water they're carried by the pollen!!

does plants go through alternation of generations?

yes! -what shifts is what is dominant (the gametophyte or the sporophyte) -as time goes by, the sporophyte becomes dominant and the gametophyte looses its independent and becoming dependent on the sporophyte. -gametophyte becomes very reduced in angiosperms

Alternation of Generations - General

•Diploid sporophyte plant produces haploid spores through meiosis •Spores divide by mitosis and develop into haploid gametophyte plants •Haploid gametophyte plant produces haploid gametes through mitosis -happens whether it is a moss gametophyte plant, a fern gamerophyte, if it is a gametophyte •Gametes fuse to form diploid zygotes, which divide by mitosis and develop into diploid sporophytes, or a gametophyte that is inside a pollen grain.

Plant Ovules

•matures into the seed -It is the site of gametophyte development, fertilization & embryo development

what things about plants that make then asexual?

•the Repetitive units in plants -Internodes & nodes -this makes them capable of being asexually reproduce in some cases ex: Ginger from rhizomes, aspen from adventitious buds