(T)LAB: Explain the alternation of generations in plants
- (T) Alternation =(switch), generation = stages. Two stages that it switches through = sporophyte and gametophyte stages.
- 1. Sporophyte starts diploid
- 2. They divide by meiosis to form haploid spores (half)
- 3. Spores always produced by meiosis (common between plants/protist?)
- 4. Spores germinate and then then = gametophyte (Sex cells/sperm/egg)
- 5. Plants produce sex cells by mitosis, WHY? because its already at haploid state therefore don’t need to go by meiosis
- 6. Zygote forms (diploid)
- 7. Zygote splits by mitosis then back to sporophyte
- Spores produced by meiosis*****
(T)Why are Nonvascular plants primitive, small plants that grow in damp, shady places?
- Non vascular plants grow in damp why? Because they can only get
- water/minerals by diffusion, don’t have vascular tissue, thats why short
- and small and in damp locations. Diffusion can only occur certain
- distance therefore limits where they can grow
Explain the life cycle of a moss
Bryophyte life cycle.
1. Spores develop into haploidprotonemata.
2. Protonemata produce "buds" that undergo mitosis.
3. Buds develop into gametophyte bearingantheridia or archegonia.
4. Sperm swims to egg inarchegonium.
4. Fertilized diploid zygotedevelops into sporophyte embryo.
5. Sporophyte emerges from thearchegonium.
6. The small sporophyte is dependent on the largegametophyte.
7. Spores develop by meiosis insporangium.
(T)Why are moss “primitive plants”?
!What are the adaptations for terrestrial existence?
- Why moss primitive? = They need water for fertilization because they
- produce flagellated sperm in order to swim to the egg to fertilize it =
- need damp environment if dries up, its okay for moss, another reason it survives for long time cause it produces spores
- ALSO, Primitve
- features of moss also: Main part of plant is visible is the
- gametophyte, gametophyte is dominant , permanent part of the plant and
- most obvious part of plant, think of moss, think of leafy part.
- Sporophyte growing out of gametophyte, dependent on gametophyte for
- water, nutrients, minerals thats why it grows on top of it
- are the features that make it well adapted on life on land? = spores =
- resistant in structures , no metabolic activity , protective coat , can
- stay dormant til environment improves(ADVANTAGES) big benefits), the
- fact that they have multiple sex organs and the sex organs protect the
- sex cells and providing nutrients for it to stay alive. ONly time sperm is vulerable when they leave antheridia, archegonia protects egg and ZYGOTE. AND the embryo.
What is a trend in plants? Except Moss?
sporophytes are dominant(= major trends in life cycle)BUT in moss gametophytes are dominant
sporophytes become bigger, gametophytes become smaller
Vascular plants are modern large plants that have xylem and phloem. What are the functions of xylem and phloem?
- -xylem is designed for the transport of water and minerals (don’t say
- nutrients). Because it has thick cell walls (the cell walls also contain
- lignin-->hard) it also provides great support, like the skeleton of the plant (more inorganic molecules)
- wood we use xylem , very supportive structures
- phloem = function = transport of nutrients mostly sucrose, but also amino acids, vitamins, hormones. (organic molecules)
What are some examples of seedless vascular plants?
- Examples of seedless vascular plants →
- 1. lady fern(good for bladder infection),
- 2. whisk fern(no roots no leaves,
- just stem, its supported by horizontal stem to support it, yellow stuff =
- sporangium, no leaves, whats carrying out
- photosynthesis?-->STEM(stem taking over job of leaf)
What carries out photosynthesis in whiskferns?
the STEMS, (stems taking over function of leaves)
Explain life cycle of fern
Fern life cycle.
1. Sporangia release spores.
2. Spore develops into asmall, bisexual,photosyntheticgametophyte.Gametophyte produces sperm in antheridia and eggs in archegonia.
3. Sperm swim to eggs inarchegonia.
4. Zygote develops intolarge sporophyte.
5. Clusters of sporangiaform in sori.
(T)Why are ferns still “primitive plants”
- → What part primitive? = flagellated sperm in this cycle(has to swim through rain droplets to get to other plant)
- → Ferns are still primitive plants because they have to get from one plant to another by rain droplets.
(T)Explain why the sporophyte is better adapted than the sporophyte of moss(Advantage in having dominant sporophyte?)
- advantage of having large sporophyte(dominant)? ->
- 1.Produces more
- 2. able to further disperse the spores(able to disperse
- greater distance)
- 3. horizontal part of fern below, stem safe from
- predators/climate = stem
- 4. sporophyte = independent, not dependent on
- gametophyte after fertilization
!Antheridia and archegonia mature at different times. Why?
- and archegonia mature at different times because self fertilization
- won’t occur. Antheridia first, archegonia second.
cross fertilization in ferns, why is cross fertilization wanted?
Because genetic variation
Whats advantage of having only leaves shown on fern?
Because protected by predators and climate (animals will eat leaves but won’t be able to eat stem)
What is gymnosperms?
A type of seed vascular plants that are ever green conifers that have "seeds", which are "not surrounded by a fruit"
Explain life cycle of a pine
Gymnosperm life cycle.
1. Sporophytes bear cones.
2. Pollen cones containmicrosporangia.
3. Ovulate cones containmegasporangia.
4. After pollination, amegaspore develops into a female gametophyte.
5. The pollen grain germinates asperm cell which fertilizes an egg/
6. The ovule becomes a seed.
What are the adaptations for terrestrial existence of a pine ? (advancements?)
- big advancements here?
- 1. pollen grains
- 2. sporophytes huge therefore
- producing so many spores
- 3. fact that its so much bigger then
- gametophytes it makes cones that can wrap itself around gametophytes,
- protecting its sex organs)
- 4. Wings on pollen grains and ALSO wings on seeds** → Embryo that’s dormant state waiting for that perfect climate
- for it to come out and protected and has stored food
(T)Compare monocots and eudiocts in angiosperms
- 1. ONE cotyledons (MONO)
- 2. Veins in parallel fashion (composed of xylem and phloem)
- 3. Herbaceous stem=(stem soft and green, vascular tissue scattered)
- 4. Fibrous root system (threadlike/thin)
- 5. Pollen grain has one opening(pollen grain creates sperms
- 6. Flower in multiples of 3
- 1. TWO cotyledons (DI)
- 2. Veins branched apart (not parallel)
- 3. Woody stem(vascular tissue forms in a ring)
- 4. Tap root (thick part going down and smaller branches going around
- 5. Pollen grain has many openings (more choices for sperm to get out)
- 6. Flower parts in multiples of 4 or 5
Advantages of fibrous root system/taproot system
- Advantage of taproot because of depth goes lower so can get more water minerals deep in soil
- fibrous increases surface area for more water and minerals
(T)What is the structure and function of a flower?
- green part of flower, typically covers the bud, photosynthesis cause green
- inside ring of sepals, colour part of flower , they attract animals to help with pollination
- male structure
- stamen - male reproductive part of flower. a. anther=production of pollen grain(what produces sperm nucleus, what will become male gametophyte part of the plant)
- b. filament = raises anther higher up - increases chances of animals rubbing on anthercarpel
- sigma(top flat part, sticky, perfect for receiving the pollen grain, landing
- platform) pollen tube grows out of style(style is hollow) lets sperm
- nucleus through
it contains the ovules waiting to be fertilized by pollen
what contains the female gametophyte part of the plant , called embryo sac(female gametophyte) produces egg
(T)Why is stigma of flower, higher then the anther?
- Because if they were at same level, then pollen grains would more likely go on carpel and then there would be more self pollination. Stigma higher = self pollination
- must slimmer, stigma higher more pollen grains will land on it
(T)Explain life cyle of angiosperms
1. Anthers contain microsporangia which produce microspores by meiosis.
2. Microspores form male gametophytes(pollen grains) by mitosis.
3.Ovaries containovules where megasporangia produce megaspores bymeiosis.
4. Megasporesform female gametophytes(embryo sacs) bymitosis.
5. Afterpollination, double fertilization occurs.
6. The diploid zygote develops into an embryo within a seed.
7. A seed uses the triploid endosperm as food to germinate into a large sporophyte.
Whats unique about cycle of angiosperms? Explain. Advantage?
Embryo sac undergoes double fertilization.(2 end products)
- Why is double fertilization so important? (Producing of embryo and food at
- the same time, advantage?) Making stored food only when you know you
- have fertilization (Not wasting energy), making food when you KNOW
- there’s an embryo present, Like (WOMEN, don’t produce milk til they get a
(T) Understand life cycle and know parts of the flower it turns into
all other parts of flower disintegrates, ovule turns to seed => fruit,
- 1. Ovules
- The ovules are the parts of the flower that will turn into seeds. The
- seed is made up of many parts. The roots come out when the seed sprouts.
- They suck up water so that the true leaves will be able to transform water
- and sunlight into oxygen and food for the young plant. The cotyledons are
- the first leaves to appear, and they supply food temporarily to the embryo.
- The true leaves won't appear until later. The stem is tucked inside the
- seed and it will sprout to hold up the flower.
- 2. Stem
- The cotyledons which were talked about earlier, still have the same
- purpose, only they are above the ground. They shrivel up and die when the
- true leaves come. The true leaves as mentioned before still do photosynthesis,
- or make food. Soon after they come, the plant has a growth spurt. Buds then
- come in. Buds are the unopened flowers.
- 3. Petals
- On the flower there are petals. Petals are the brightly colored parts
- that most of us notice first.They are brightly colored so bees are attracted.
- Bees are also attracted to them because bees see patterns on the petals
- that are only visible in ultraviolet light, because bees have ultraviolet
- 4. Stamen
- The stamen is the male part of the flower. There are two parts on it,
- the anthers and the filament. The filament just holds up the anthers. The
- anthers produce pollen. Pollen is the sticky stuff that some of us are allergic
- to. That stuff somehow gets into another flower's pistil.
- 5. Pistil
- The pistil is the female part of the flower. It is made up of three
- parts: the stigma, the style, and the ovary. The stigma is a sticky part
- at the top of a pistil. It gets pollen stuck on it. Then the pollen burrows
- down the long, skinny style. It gets into the ovary, or the "nursery"
- for unfertilized eggs. It then fertilizes them. When that happens, the style
- gets longer and fatter. It turns into either a pod or a fruit. Either way,
- inside lay the eggs. When the pod/fruit opens, the whole cycle begins again.
- 6. Sepals
- The sepals are the opened buds. They are right under the petals at the
- very top of the stem. They look like they are holding the flower in place,
- but the flowers actually came out of them!
How do ﬂowers attract only certain species of animals?(EXAMPLES)
- 1.Scotch Broom Flower (blues/yellow bees like) - perfect landing platform
- for bees, since only yellow/blue flowers the pollination very specific
2. Madagascar orchid
- animal must have mouth with 28cm long to pollinate , Darwin was right! moths like sweet flowers and yellow/white flowers(moths are nocturnal)
3. Cacti flower
= large opening for bats, its white also so it stands out(bats are nocturnal), sweet nectar and fragment smell
- 4.trumpet honeysuckle = perfect for humming birds(red/pink range), shape
- of flower tubular therefore only beak of humming birds can fit , birds
- have a very bad smell sense
- 6.skunk cabbage - stinks, vomit smell, fecal smell, colour = reddish,
- dark colour, attracting flies, to help disperse smells it raises it
- temperatures so smell is worst, melts snow to give off smell
5. spider orchid
- looks like a spider , wasp eats spiders and lays egg for baby wasp to eat spider
(T)Why is pollination in angiosperms more effective than gymnosperms?
Angiosperms are more specific since only certain animals are attracted to certain flowers while gymnosperms pollinate by wind so it is very random!
!What is the function of fruits?
Surrounds the seed(ovary) and helps it survive, plus the seeds are like the babiesseeds = embryos (babies)