Exam 2 Flashcards
What is in the SAR clade?
Stramenopiles (Diatoms, golden algae, brown algae
alveolates ( Dinoflagellates, apicomplexans, ciliates)
Rhizarians (forarms, cercozoans, radiolarians)
What are in Excavata
diplomonads
parabasalids
Euglenozoans
What are in Archaeplastida?
Red algae
chlorophytes
charophytes
land plants
what are in unikonta?
Ameobozoans ( slime moulds, tubulinids, entamoebas)
opisthokonts ( nucleariids, fungi, animals, choanflagellates)
What are protists characteristics?
-extremely diverse
-mostly unicellular
-some colonial
some multicellular
How are protists like plants?
photosynthetic,
sessile
How are protists fungus- like?
-heterotrophic (absorption)
-relatively sessile
How are protists animal like?
-heterotrophic (ingestion)
-motile
what are protists habits?
-aquatic (marine and freshwater)
-moist terrestrial
-parasitic
reproduction in eukaryotes
-one of four conditions that define “life”
-most eukaryotes reproduce sexually
-some also reproduce asexually through binary fission, budding, fragmentation
-in most cases of sexual reproduction, haploid gametes are formed via meiosis (gametic)
-return to the diploid state via syngamy (fusion)
structural and functional diversity is greater in_____ then any other group
protists
protists may be -
unicellular, multicellular, or colonial
what is mixotrophy?
the combination of photoautotrophy and heterotropy
What is heterotropy?
getting its food from other plants or animals, or relating to such living things
What is photoautotrophy?
organisms that carry out photosynthesis
Protists acquire their energy through processes of -
photoautotrophy
heterotropy
mixotrophy
Syngamy
The fusion of the male and female gametes during fertilization
Supergroup Excavata: euglenozoans
-can be photosynthetic or heterotrophic
-unique flagella used for locomotion
-have chlorophyll a and b
-no cell wall composed of cellulose
-freshwater euglena are mixtotrophic
-store energy as a carbohydrate called paramylon
What super group is euglenozoans (euglena) from?
Excavata
How do euglenids differ from green algae?
they do not have a cell wall composed of cellulose
What super group are alveolates from?
The SAR clade
What are (ciliates) stentors?
- a grey-green ciliate that possesses minute hair-like structures called cilia in rows along the oral groove
-they feed on other microscopic organisms by sweeping food into the oral groove and enveloping it in a food vacuole for absorption
alveolates: dinoflagellates
-predominantly marine, single celled organisms
-many have photosynthrtic pigments, a few are are mixotropic
-other nonpigmented species are heterotrophic or parasitic
stramenopiles: Diatoms
-unicellular photosynthetic algae
-major part of plankton in marine and freshwater habitats where they are transported by currents and turbulence
-cell wall have 2 valves made of silica
-shape is normally described as centric or pennate
-has 2 views, valve, and girdle
Stramenopiles : Brown algae (laminaria)
-common in temperate marine waters
-cell walls composed of cellulose and derive their nutrition from photosynthesis
What are supergroup Archaeplastida
key photosynthetic protists
red algae (polysiphonia)
-marine organisms
-call walls are composed of cellulose
-has chlorophyll a and phycoerythrin
-some are parasitic on other red algae and lack those pigments
-lack flagellated stages in their life cycle so they are entirely dependent on currents for fertilization and dispersal
What supergroup is red algae in?
Archaeplastida
what is Chlorophyll a
A photosynthetic pigment
What is phycoerythhrin?
A photosynthetic pigment that is adapted to take advantage of a wide specrum of light in various depths of water
What is polysiphonia?
a widespread marine alga with a branching, filammentous thallus
filaments can reach up to 30 cm in length and are composed of a single elongated central cell coated with several layers of cells
Green algae: chlorophytes and charophytes
-most ecologically and evolutionarily important algae.
-primary souce of food for aquatic animals and health food supplements for humans
-many similarities to land plants including having cellulose cell walls
-both sexual and asexual
Two types of green algae
chlorophytes and charophytes
Chlorophytes (volvox)
-unicellular, colonial, filamentous-like, and parenchymatous
-most are free living, some chlorophytes are known to form lichens in a mutalistic relationship with fungi
-inhabit freshwater environments although some species are found in marine and terrestrial environments
Volvox
-highly developed colony
-hallow ball
-ball composed of hundreds of flagellated cells that cannot reproduce in isolation
-daughter cells form inside of and are eventually relased by the large colony
Charophytes (spirogyra)
-exhibit diverse thallus (body) forms
-inhabits many different types of environments
-most closey related to land plants
-the types of cellulose, synthesizing protein in the plasma membrane, the presence of peroxisomes, and the process of forming land plants and the charophtes
Spirogyra
A fliamentous member of the charophytes with an elongated chloroplast
what supergroup is amoebozoans
unikonta
Ameobozoans: slime moulds
-physarum
-sometimes referred to as “fungus-like” protists
-important role as decomposers in terrestrail habitats and so resemble fungal organisms
-often colourful and live an almost anything moist (soil, rain gutters)
-in vegetative state they are thin, streaming masses of multinucleated protoplasm referred to as a plasmodium
-engulf bacteria and organic compounds by phagocytosis
-when food and/or water supply runs low, plasmodimum stops moving and begins to form a series of small mounds which develops into a mature sporangium that produces spores
What is a sporangium?
-a spore-containing sac that produces spores
Ameobozoans: Tubulindis
(ammoeba proteus)
-sometimes referred to as animal-like” protists
-they move by forming and extending a pseudopodium at any point on their body surfaces
-feed by phagocytosis
-cytoplasm is into two regions
-ectoplasm, nonflowing and more peripheral in position
-endoplasm, more fluid and more central in position
-plasma membrane which has adhesive properties and new pseudopodia attach to the substrate as they are formed
Protist table
-…-
Why is green algae closest to land plants?
-has chlorophyll a and b
-caretenoids
-xanthophylls
cell walls are predominantly composed of cellulose and photosynthetic products are stored as starch
What makes land plants and algae different?
they are distinguished from the charophytes by the development of apical meristemms, spores with sporopollein enriches walls within sporangia, and possessing multicelluar gametangia (antheridia and archegonia, and possessing an embryo (sporophyte) that develops within the archegonium
all plants, as well as some green and brown algae exhibit-
life cycles with sporic meiosis
-all organisms with this life cycle exhibit alternation of generatinos, where a multicellular, hapoid form of the organism (gametophyte) alternates with a multicellular diploid form (sporophyte)
what is isomorphic alternation of generations?
if two generations appear to be identical
What is a heteromorpic alternation of generations?
If the gametophyte and sporophyte stages are phenotypically distinct
PineLife-cycle table
–…—
Why do land plants echibit a variety of morphological and physiological modifictations of their body organizations?
-they are responses to selection pressures assosicated with the move from an aquatic to a terrestrial environment
differences between plant and water environments for plant growth
aqatic environment:
-water is available to all cells and also acts as a supportive medium
-oxygen, CO2 and minerals required by a photosynthetic organism are in solution and so most cells are capable of photosynthesis
Terrestrail habitats:
-light, oxygen and CO2 areavailable but water is often limiting, and when present is noramlly in soil
-photosynthesis and nutrient absorbation are often seperated in terrestrial photosynthetic organisms
what specialized cells have plants evolved
cells for photosynthesis, for transport of organic and inorganic nutrients, and those for reproduction
unlike animal cells, a typical plant cell possesses what?
a rigid cell wall that surrounds the protoplast
What is the protoplast?
it comprises the contents of the cell: the plasma membrane, the cytosol, the nucleus, and other membrane-bound structures such as endoplasmic reticulum, mitochondria and chloroplasts
Living, metabolically active plant cells have a-
primary cell wall
-composed of cellulose and is somewhat flexible to permit growth
some plants have a secondary cell wall
-deposited inside the primary cell wall after the cell has stopped expanding
-may also contain a plant polymer called lignin
what is lignin
a plant polymer
-a chemcial that renders the cell wall infelxible
parenchyma cells
-unspecialized cells (not differentiated) that are thined walled and many sided
-make up the bulk of the plant body and perform virtually all the metabolic activities required by the plant
Collenchyma cells
cells with unevenly thickened, nonlignified primary cell walls that allow the cells to stretch
-are thickened in the corners
-They do not have a secondary cell wall and are alive at maturity
What is the funtion of the collenchyma cells structure is?
To give the plant strength
in which regions of the plant body would you expect to find coolenchyma cells?
under epidermis
peticles
leaf veins
young stems
sclerenchyma cells
-thick, ignified secondary walls
-lack a protoplast at maturity
-provide strength and support in regions of the plant that have ceased elongating
What is the major function of cells with a secondary cell wall?
To provide additional strength
when they are functionally mature, Sclerenchymma cells generally have no protoplast and therefore are not living. Why might this be?
They have thick secondary walls which do not elongate during cell growth
What are tissues?
-Groups that perform similar functions
-may be simple or complex
What are simple tissues?
only a single type of cell is found
-the name reflect on the type of plant cell of which they are composed
ex- tissue solely composed of collenchymma cells would be called collenchyma tissue
What is complex tissue?
-are composed of more than one cell type
-defined by their function and location
theres three types of complex tissues:
- xylem, pholem, and epidermal
What are xylem tissue?
-complex
-made up of a number of cell types (including parenchyma cells and a veriety of sclerenchyma cell types)
there are more sclerenchyma cells than parenchyma
the principle water conducting tissue in vascular plants
-actual transport of water and minerals throughout the plant that have lignified secondary cell walls at maturity
-parenchyma cells do not participate directly in conduction
Why are the functional transporting cells living or nonliving? why?
Nonliving, so their cell walls serve as conduits so the water can move
What is phloem tissue
-an aggregation of parenchyma and sclerenchyma cell types
-functions prinipally as a conducting tissue for photosynthate (food) in vascular plants
-conducting cells are derived from parenchyma, sclerenchyma cells provide support
-more parenchyma cells than sclerenchyma cells
how are xylem and phloem functionally different from each other?
Xylem transports and stores water and minerals.
-larger
Phloem transports sugars, proteins, and other organic molecules in plants
-smaller
Epidermal tissue
-makes up the outermost cell layer of the plant body
-covers leaves, floral parts, fruits, seeds, stems, and roots
-one cell layer thick and is sometimes covered with a waxy cuticle on aboveground parts
-stomata are pores in the plant epidermis of most leaves that are surrounded by 2 guard cells, which controls the opening and closing of the aperture
What is the purpose of the waxy covering on plants?
To prevent water loss
what is the function of guard cells
- help to regulate the rate of transpiration by opening and closing the stomata.
Would you predict that the upper and lower surfaces of a leaf would be identical in appearance? Why?
No, the upper part of the leaf is lighter then the lower half because it tends to get more sunlight
where can you find specialized parenchyma cells?
on the epidermis
What are parebchyma cells?
on root tips, these cells form root hairs and function to increase surface area for absorption of water and minerals
-on leaves and stems these cells are called trichomes and look like little hairs
Seedless nonvascular plants
-bryophytes
-they phylum hepatophyta (liverworts) and phylum bryophyta (mosses), make up the seedless nonvascular plants
-have a simple ¨body plan¨ calleda thallus
exhibit heteromorphic alternation of generations, however, in bryophytes, the gametophyte is the dominant generation
what is a thallus?
-a ¨body-plan¨
-of a bryophyte- they are pretty small and not differentiated into stems, leaves and roots, and therefre it lacks a specialized conduction system
What is phylum hepatophyta?
liverworts
Phylum hepatophyta
-liverworts
-pores leads to air chambers benealth the upper surface of the thallus
-Rhizoids
The function of pores
regulate gas exchange through their stomata
What are Rhizoids
-tiny thread-like structures thats function is to anchor the thallus to the substrate and allow the plant to absorb water and nutrients directly from the substrate
Asexual reproduction for liverworts
-gemmae cups develop on the surface of the thallus
-the cups produce samll packets of cells called gemmae that are dispersed by splashing out in the rain
Are gemmae formed by mitosis or meiosis. what is its ploidy?
-haploid (n)
-mitosis
Sexual reproduction for liverworts
the little umbrellas bear antheridia or archegonia
-fertilization results in a sporophyte that remains permanently attached and dependent on the gametophyte
Archegonia
produces eggs
Antheridia
produces sperm
Phylum Bryophyta
-mosses produce protonema as the first satge after spore germination
-spores are round tan objects that will grow by mitosis to produce protonemata
what is protonema?
thread-like structures
-buds that form will eventually develop into leafy gametophytes, which is attached to a substrate by thin filaments of cells called rhizoids
are protonemata haploid or diploid?
Haploid
What will happen when leafy gametophytes mature?
-they will produce gametangia
Are eggs haploid or diploid?
Haploid
is sperm haploid or diploid
haploid
are sperm produced by mitosis or meiosis?
Meiosis
The sperm if these plants is flagellated. What kind of environment conditions would be required for the sperm cells to reach the egg cells for fertilization
They need water and so they must be in moist habitats
sporophyte and gametophyte for moss
-sporophyte results from mitotic divitions of the fertilized egg in the archegonium and in dependent on the gametophyte for some of its nutrients
life cycle table
—…—
The earlier vascular plants were-
seedless
What are the two living phyla of seedless vascular plants that are still alive?
Monilophyta
lycophyta
what is the dominant generation for seedless vascular plants?
the sporophyte generation
phylum monilophyta
-most ferns are related plants, are homosporous
-fern sporophytes are diploid
-ferns have an underground stem (rhizome), from which fronds (leaves0 arise
-pinnae
-the frond is a megaphyll that is characterized by a complex vascular trace
What does homosporous mean?
-the plant produces only one size of spore in its sporangia
-the spores germinate and grow into free-living gametophytes bearing both antheridia and archegonia (a bisexual gametophyte)
-bisexual gametophyte is called a prothallus
Phylum lycophyta
selaginella, a heterosporous species in this phylum
-plant produces small cones called strobilil on the tips of the branches
-has mircophyll types of leaves which are only in lycophytes
-the single strand of vascular tissue in the centre of the selaginella leaf
-a few members have evolded heterospory, so the products of meiosis are two different sizes of spores, microspores and megaspores
-these spores germinate (grow) and become microgametophytes and megagametophytes that mature inside the spore wall
What does selaginella do?
-produces 2 types of sporangia and two kinds of spores- megaspores in megasporangia, microspores in microsporangia
-megaspores and microspores germinate to produce unisexual gametophytes that are retained in the spore
-megaspores germinate to form megagametophytes (female gametoplytes) that produce female gametes (eggs)
-microspores germminate to form microgametophytes (male gametophytes) that produce male gametes (sperm)
what are pinnae?
a frond that is divided further into little “leaf-like” segments
What are clusters of sporangia called?
sori (single, sorus)
what is an indusium?
a flap of pinna tissue that covers each sorus
What is the annulus?
-a ring of thick-walled cells surrounding each sporangium
-it opens the sporangium and disperses the spores
What is a fern gametophyte also known as?
- a prothallus
-they are bisexual, free-living, and photosythetic
-at maturity, it is flat and heart shaped
what is the function of prothallus
to produce the gametes
How is the fact that antheridia and archegonia mature at different times on the same prothallus adaptive in homosporous ferns?
Because it increases the chances of cross-fertilization as well as genetic variation
How is the sporophyte developed in ferns?
-the sperm is released from the antheridia, swim to the neck of the archegonium and then travel down to the egg.
-the fertilized egg (zygote) develops into a sporophyte which then attaches to and is dependent upon the gametophyte for nutrients
-then becomes free-living while the gametophyte shrivels and dies
Life cycle table -pg 85
–..—
where does fertillization take place in selaginella
on the megagametophyte
strobilus is made up of many fertile leaves called-
sporophylls, which has a sproangium on its upper surface
-some sporangia have megaspores in megasporangia on megasporophylls, while others have small spores, microspores in microsporangia on microsporophylls
fig 5.5 86
–…–
What generation is selaginella from?
gametophyte
Protonema ploidy and function?
-n
-they form the earliest stage of development of the gametophyte
Rhizoids ploidy and function?
-n
-absorbs water and nutrients from the soil
Antherisdium ploidy and function?
-n
-produces and holds sperm cells
Archegonium ploidy and function?
-n
-produces and holds the eggs
Sperm and egg ploidy and function?
-n
-used for reporduction- fertilization
zygote ploidy and function?
-2n
-fertilized egg which develops into spotophyte embryos
Capsule ploidy and function?
-2n
-produces the spores
Peristome ploidy and function?
-n
-releases the spores
Operculum ploidy and function?
-2n
-controls the release of spores over a long period of time
are spores in the mosses and ferns produced by mitosis or meiosis?
meiosis
Why is water still required in ferns and clubmossess to complete the life cycle?
So the sperm can move through the water and get to the egg
What are the three characteristics in seedless vascular plants that allow them to survive in terrestrail habitats
-roots
-vascular tissue
-lignin
Traits shared by charophyceans and
land plants:
- Possession of chlorophylls a + b, carotenoids, and xanthophylls
- Cell wall of cellulose
- Photosynthate stored as starch
Also:
– Rings of cellulose-synthesizing proteins (see figure)
– peroxisomes
– Structure of flagellated sperm
– Formation of a phragmoplast
Derived traits of land
plants:
apical meristems
* walled spores in sporangia
* multicellular gametangia
* dependent embryos
All land plants also undergo sporic meiosis, which is also referred to as ‘alternation of
generations’.
Basic Plant Anatomy
cell wall - rigid
* primary cell wall
* cellulose, somewhat
flexible
* Always present
* secondary cell wall
* cellulose and lignin, inflexible
* Sometimes present
* plasma membrane
* protoplast (living contents of cell)
Heteromorphic vs Isomorphic Alternation of Generations
Ulva represents isomorphic A
of G as the gametophyte and
sporophyte look identical
Ferns represent
heteromorphic A of G as the
gametophytes and
sporophytes look different
Plant Cell Types: Parcnchyma cells
Parenchyma cells
* primary cell walls
* unspecialized
* metabolically active
Plant Cell Types: Collenchyma cells
Collenchyma cells
* primary cell walls
* Support/growth
* living
Plant Cell Types: Sclerenchyma cells
Sclerenchyma cells
* secondary cell walls
* support in areas that are done growing
* no protoplast at maturity
Simple tissue
- single cell type
- named after cell type
- eg. collenchyma tissue is composed of collenchyma cells
Complex tissue
- more than one cell type (or highly specialized)
- Three types: xylem, phloem and epidermal
Phloem
- parenchyma and sclerenchyma
- nutrient transport
Xylem
- parenchyma and sclerenchyma
- water transport
Seedless Non-vascular Plants:
small
* no true stems or roots
* no specialized conduction
system
* Heteromorphic alternation of
generations
* gametophyte dominant
generation
* high dependence on water to
complete life cycle
Phylum Hepatophyta
- Common name = Liverworts
- Name from the appearance of the plant body (thallus) – looks like the lobes of a liver
Seedless Vascular Plants
- specialized conduction system
- lignified cell wall for support
- sporophyte generation dominant
Phylum Monilophyta L
homosporous
- Bisexual gametophyte called a prothallus
- Leaf a megaphyll
Phylum Lycophyta L
Most are heterosporous, including Selaginella
- Leaf a microphyll
Plant Adaptations for Dry Land 1)
Reduction of gametophyte
generation
- retained within sporangia
* protection from drought
and UV radiation
* nutrients obtained from
sporophyte
Plant Adaptations for Dry Land 2)
Heterospory
- ovule - megaspore retained within sporophyte, produces
female gametophyte, which produces an egg cell in
protected environment - pollen - designed to be dispersed from parent plant to
ovule
Plant Adaptations for Dry Land 3)
seeds
* protective coat
* food supply for embryo
* wide dispersal ability
* Seeds can be interpreted as a fertilized ovule; the embryo, a food supply, a protective coat derived from the integument
Gymnosperms
‘naked seeds’
Phyla:
Cycadophyta
Ginkgophyta
Gnetophyta
Coniferophyta
Gymnosperm Phyla
Phylum Gnetophyta
Phylum Ginkgophyta
Phylum Cycadophyta
Angiosperms
- flowers and fruit
Phylum Coniferophyta
drawing
Angiosperms L
Phylum Anthophyta
pic of flower parts
Inferior vs superior ovary
drawing
angiosperm cycle
darwing-pic
seed plants have become the most ___ feature of the terrestrial landscape
dominant
what do seeds offer?
protectino fron unfavourable environments and stored food reserves for developing embryos
All seed plants are-
heterosporous
-a dominant sporophyte generation and a much-reduced gametophyte generation that develops on the sporophyte
Where is the dispersal of male gametes on seed plants?
it takes place in pollen grains and eliminates the requirment for water in fertilization
The gymnosperms
-all are woody perennials
-produce seeds on structures that are open and exposed to the surrounding environments (naked seed), rather then enclosed in an extra protective structure as in the angiosperms
-produce multi-nucleated pollen grains for protection and transportation of male gametes for fertilization
-seeds develop and mature in cone-like structures called strobili before being realsed for dispersal
What are the 4 extant phyla of gymnosperms?
Cycadophyta
Gnetophyta
Ginkgophyta
coniferophyta
Cycadophyta
perdominant during dinos
-thrive in tropical and sub-tropical regions
Ginkgophyta
-only has one species, ginkgo biloba, thats living
Gnetophyta
-only three exist
-ephedra (type of ephedrine) the only species in North America and can be found in arid regions
Coniferophyta
-the most abundant and successful of the gymnosperm phyla
-consists of trees like pines, spruces, firs, and larches
Cones are composed of several leaves that bear___ on their lower surfaces
microsporangia
Can you distinguish the microsporangia and the mircosporophylls?
Microsporangia is the modified leaf that contains the microsporophylls
What is the microsporangia in male cones?
The sites of meiosis
Microspores in male cones
-they develop into pollen grains which consists of 4 cells
What are the 4 cells of a pollen grain
tube cell
generative cell
prothallial cells
sterile cells
What is a tube cell?
-it is responsible for growth of the pollen tube (often it is only the nucleus of the tube cell that is visible
What is a generative cell?
-it will divide to produce two sperm cells and 2 prothallial or sterile cells
what are the prothallial and sterile cells?
they represent the remains of the vegetative body of the male gametophyte
what is the wings for?
to aid in its dispersal
what gender of cone is more complex?
Females
megasporangia
upper surface of a flat structure called the scale, which in turn sits above another structure termed a bract.
-they are surronded by extra layers of tissue called the integument and are now referred to as ovules
Pine ovule pic
—…— pg 94
in the gymbosperm life cycle
a pollination droplet captures th epollen grains at the opening to the micropyle
-droplet dries, pollen grains are pulled into the pollen chamber where they germinate
-vegetative cell becomes the pollen tube that grows into the archegonim where the egg cell has formed
-fertilization happens when the 2 non-motile sperm nuclei are discharged from the pollen tube into the egg cell
-one nucleus fuses with the egg nucleus and one degenerates
-zygote develops by mitosis to form an embryo surrounded by female gametophyte tissue
-tissue serves as a nutrient supply for the young developing sporophyte
-the integument deelops into a resistant seed coat
-the seed then, is a package containing an embryo, food storage material, and a protective coat
What tissue is the seed coat derived?
The integument
the embryo of a seed is sporophyte or gametophyte?
Sporophyte
The angiosperms phylum?
anthophyta
The angiosperms
-flowering plants are the most diverse and widespread group of plants
-250,000 species
-anthophyta- antho = flower
phylum are divided into 2 groups:
monocots and dicots
Phylum anthophyta has 4 main groups
Group monocots
includes grassed, lilies, palms, and grain crops
group dicots
includes roses, legumes, sunflowers, and trees like oaks and poplars
-paraphyletic
Phylum anthophyta has 4 main groups
-basal angiosperms
-magnoliids
-monocots (largest)
-eudicots
Most angiosperms are___
Hermaphroditic
-sexual reproduction can occur either through self-fertilization or cross-pollination (outcrossing)
Pollen, seeds and fruits are all adapted for__
dispersal- aided by both abiotic and biotic agents
What are abiotic agents
wind
water
gravity
-common and evident
what are biotic agents
insects
birds
other animals
-showy flowers, colour, shape, smell, and rewards attract pollinators
The flower
-a highly modified and specialized shoot whose function is reproduction
-leaf like sepals
-petals, coloured for attraction, 2nd whorl
-stamens comprise the 3rd whorl.
-composed of a slender stalk, termed the filament, and a pollen-bearing anther, derived from a microsporangium
-develop from microsporophylls
-carpels constitute the 4th (innermost) whorl.
-composed of a swollen ovary, containing one or more ovules, a style, that connects the ovary to the stigma, and a stigma, the pollen receiving site
-develop from megasporophylls
-might be more then one in a flower depending on the species- they remain seperate, or they fuse together to form a single reproductive structure (the gynoecium)
The pollen grain (reduced male gametophyte)
-lilium anther
-2 cells:
-tube cell
-generative cell
anther
-derived from a microsporangium
-microspores produced inside the anther develop into pollen grains
are microspores from pollen grains produced by mitosis or meiosis
meiosis
Are pollen grains haploid or diploid?
haploid
only two cells visable in pollen grain. what are they and their functions?
generative cell: to act as the reproductive cell of the pollen grain
tube: to move the male gametes to the ovule
The female gametophyte
lilium ovary
there are 6 ovules visable: megasporangium + megaspore + integuments
-each ovule is attached to the centre axis of the ovary by a stalk called the funiculus
in typical angiosperms, a diploid meiocyte inside the megasporangium ___
divides meiotically to produce 4 haploid nuclei
-3 degenerate, 1 undergoes mitotic divistion 3 times to get 8 haploid nuclei
-nuclei comprise the female gametophyte, or embryo sac
-during fertilization, the pollen tube produced by a male gametophyte will grow through the micropyle to deliver 2 sperm to the embryo sac
pg 99
Lilium embryo sac
-3 antipodal cells at the end of the sac (opposite the micropyle)
-2 nuclei in the central region of the embryo sac, termed the polar nuclei
-3 nuclei at the micropyle end of the embryo sac, cosisting of 2 synergids surrounding the egg
Double fertilization
1 sperm nucleus fuses with the egg to form a zygote (2n), which eventually divides by mitosis to become the embryo
-second sperm nucleus does not degenerate but instead fuses with the 2 polar nuclei to form the endosperm nucleus (3n)
-endosperm nucleus then divides to form endosperm tissue, which provides nutrition for the devlopin embryo
-the fertilized ovule is termed a seed
-seeds remain inside the ovary, which develops into the fruit
pg 100
The seed
-cotyledons
-embryo is located between the 2 cotyledons
-radicle
what are cotyledons
-fleshy and leaf-like in seeds
-a food storage tissue until the growing seedling becomes photosynthetic
What is the plumule
located near the top of the embryo, represents the first set of true leaves produced by the embryonic shoot apical meristem
What is the radicle?
an embryonic root that emerges from the bean seed as it splits the seed coat
The fruit
-develops from ovary wall material following fertilization of the ovules within
-as seed develop, the ovary wall simutaneously thickens to become the pericarp
-function of fruit is to protect the seeds and to aid in their dispersal
-may have one or more ovaries (true fruits) or may incoroporate other floral parts in addition to the ovary (accessory fruits)
may be dry or fleshy.
true fruits
fruits that may have one or more ovaries
accessory fruits
may incoroporate other floral parts in addition to the ovary
what are pericarps?
the wall of the fruit
Dry fruits
-may remain intact at maturity or may split apart (like legumes)
-nuts, fruit of pea and bean plants
Fleshy fruits
-have layers of fleshy tissue surrounding the seed or seeds
-berries and drupes are fleshy fruits composed of only ovary tissue
berries
-fruits with many small seeds, like grapes, bananas, or tomatoes
drupes
fruits with one large seed, such as peaches, almonds, or olives
are berries and drupes true or accessory fruits?
true, cuz they were developed by the ovary
What are pomes?
apples and pears
table on 103
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Volvox diagram
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spirangyra diagram
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Amoeba diagram
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physarum diagram
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diatoms diagram
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stentor diagram
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euglena diagram
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laminaria diagram
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steps to liverwort fertilization
1) Flagellated sperm swims up archegonial neck and fertilizes the egg
- The diploid zygote divides mitotically to form a dependent sporophyte, which produces spores via meiosis
- The spores are released, each forms a new gametophyte via mitosis
The calyptra L
a remnant of gametophyte tissue.
It is attached to the sporophyte that emerges from the archegonium
The operculum L
acts as a ‘lid’ for the capsule/sporangium
The peristome L
aids in spore dispersal
