plant classification and reproduction: lesson 9B Flashcards
importance of plants in reference to the environment and humans:
Produce oxygen (required for other organisms and humans)
Producers (because they are autotrophs) - therefore they support food webs → plant diversity increases the diversity of ecosystems
–> Food source (The baseline food source)
—> Supplying food through photosynthesis (creation of glucose)
Source of medicines, clothing (cotton), wood, paper products
Provide habitats for many species (nest, spiders web)
Act as arbon sinks that absorb CO2 from atmosphere → When the plant Dies → Carbon goes into the soil as organic matter.
—> Intake carbon and turns into co2 (photosynthesis)
Diversity of terrestrial ecosystems depends on plants
What are the general characteristics of a plant?
Multicellular and eukaryotic (have membrane bounded organelles, and a nucleus)
Autotrophic (mainly phototrophic, therefore produces its own source of food)
Cell wall is mainly composed of cellulose
Sessile (stationary)
Different life cycle from animals - Alternation of Generations
–> Can be asexual and sexual (repdouction)
—> Plants have a diploid and haploid stage, where the diploid generation produces spores and the haploid generation produces gametes
—> while animals only have diploid stage (excluding the fertilization process of gametes)
What is alterations of generations and what are its 2 life cycles?
Alterations of generations, where the plant is asexual for a period of time and within the same life cycle reproduces sexually.
Takes place in 2 stages:
Diploid stage - produce spores - asexual stage
—-> Plant in this stage is called a Sporophyte
—> Why is it asexual if this stage does meiosis? (In this stage the gametes (spores) are not coming in contact and being fertilized.
Haploid stage- produce gametes - sexual phase
—-> Plant in this stage is called a Gametophyte
—> Gametes fertilize, come in contact together.
Whats the difference between animal life cycles and a plants life cycles?
animal life cycles only have a diploid stage, where they only have diploid cells (organismsms with two sets of chromosomes) indivduals produce haploid cells (sex cells, produced by meiosis), these haploid cells come into contact (fertilize), producing a zygote, and grow into adults. A diploid stage that produces haploid sex cells
Plant life cycle alternates between a diploid sporophyte generation and a haploid gametophyte generation, both asexual reproduction and sexual reproduction.
A diploid and a haploid stage
Alterations of generations: Plant life cycle, how does it work?
CAN START ANYWHERE:
Plants diploid stage is called a sporophyte. the sporophyte diploid cells divide by meiosis to produce haploid cells (which take the form of spores).
These haploid cells are ASEXUAL (therefore do not fuse right away together to form a zygote) (Haploid cycle/generation begins) Haploid cells form asexual spores (reproductive units NOT THE GAMATES OF THE PLANT)
Spores germinate (which means it triggers the growth of the young plant) and grow into the gamtophyte indivduals (think of it as a new plant)
Once mature, they produce gamates, then gamates fertilize (come in contact), once fertilized you now have a diploid zygote, which matures into a sporophyte, which restarts the cycle.
How have plants adapted themselves to survive on land?
(How do they receive water/prevent water loss? How do they get water and nutirents? how do they do photosynthesis?)
Why do these adaptations come to be? Plants primitive ancestors lived on water.
—> The benefits of living on land = more light and co2 (which is crucial for photosynthesis)
Cons of living on land?
—> Must adapt to prevent waterloss
A) Protection from drying out/prevent water loss
Developed a waxy cuticle on their outer surface
–> Evolved characterstics because plants use to live in water now they live in land
B) System of transport (environment to plant cells)
Development of vascular tissue - xylem (water) and phloem (sugars)
C) Gas exchange (Protection to water loss)
Developed Stomata - tiny openings that can take in carbon dioxide gas from the atmosphere
—> conduct Photosynthesis
–> stomato Open/closed (controlled by guard cells)
Flow chart on how to classfy plants
are they non vascular (called brophytes) or vascular (called tracheophytes)?
If they are vascular, do they produce spores (called either a lycophyte [Club-mosses]or pterophytes [Ferns]) or do they produce seeds?
If they produce seeds are they gymnosperms (have cones) or angiosperms (seeds enclosed flowering plants)?
If the seeds are flowers, are they monocotledons or eudicotyledons?
What does sporophyte refer to? (in the alterations of generations)
Diploid stage, which produces spores, and refers to the ASEXUAL stage
–> in the diploid stage the plant does meiosis (a form of sexual reproduction) However, it does not produce GAMATES, it produces spores
Asexual = spores
What does the gametophyte refer to? In alterations of generations?
Haploid stage, which produces GAMATES, refers to the sexual phase
Sexual because it produces gamates, and in the haploid stage there is fertilization.
Sexual = gamates
Non-vascular plants are called what? and what are their characteristics?
Called: bryophytes (Simpliest land plants)
–> “Mosses” group
-> Have no seeds and are non vascular
—> ie moss, hornworts
(Live very close to the ground because they have no vascular tubes to transfer materials)
Non-vascular = no vascular tissues (no xylem or phloem
–> Have a protective waxy cuticial (waterloss protection)
–> Has stomata for gas exchange (but also protects against waterloss)
–> Only a few cms in height (Closer to the ground, because cannot transport substances to long heights)
–> No true leaves or true roots (/structures that can be truely defined as leaves or roots)
—> Live and reproduce in wet conditions (Gametes depend on water to fertilize, helps the “swimming structure” gamates come into contact)
VASCULAR PLANTS THAT PRODUCE SPORES:
Are called what?
Lycophytes (club mosses) and pterphytes (ferns)
Chatactersitics of Lycophytes and pterophytes and why are they called different things
Lycophytes are Clubmosses and pterophyes are ferns.
Clubmosses are simplie, therefore smaller and shorter compared to ferns.
Both:
No seeds: PRODUCES SPORES
Vascular plants (therefore have vascular tissues, xylem and phloem)
Contain LIGNIN (an organic polymer)
–> Key componey of vascular tissues
–> Extremely strong, makes cells walls more rigid
–> responsible for the strength of wood
HOWEVER CLUBMOSSES AND FERNS ARE NOT WOODY (do not contain enough lignin in comparacence to trees and shrubs)
–> has a well devolped vascular system, therefore the leaves (also called appendages) and “veins”
–> The stems (called rhizomes) grow horizontally below the surface of the ground)
–> leaves are called fronds
–> Reproduce sexually (egg fertlization via sperm) via water SImilar to borophyes
—–> Sexual reproduction in alterations of generations
-> Has a symbiotic mycorrhizal (fungi)) relationship
If the plant is vascular? What is it called?
Tracheophytes
If the plant is vascular and produces seeds what are the two names? (why are they named seperate things/reasoning)?
Gymnosperms (seeds in the form of a cone, therefore “naked”)
Angiosperms (Seeds in the form of a fruit, usually from flowering plants “enclosed”)
What do gymnosperms and angiosperms both have in common?
Vascular plants with seeds (there fore have vascular tissues, they have zylem and phloem)
Seeds = more efficinnt for survival and to grow more compared to ferns and mosses (because they are not limited to wet environments to disperse like ferns and mosses)
Dominant land plants (most land plants)
Male gametophyte is carried from one plant to another by wind or animals (how they male gamate touches the female gamate [fertlize] is through the wind or an animal [bee])
—> Male gamates are encompassed in pollen (the small structure that bees carry around)
—> Fertilizes the female gametophyte
Which produces a seed.
—> Seeds contain an embryo (the young plant)
**
Seed can remain dormant - allowing embryo to survive for extended periods of time until conditions are suitable for it to germinate (germantion refers to growth)**
Dormant: state of inactivity and suspended growth
How do i know if a plant is a gymnosperm?
—> Usually coniferous trees (tall trees that produce pines, spurce, cedars, etc)
–> woody and big
(Known as “the conifers”)
-> Boreal forces contain a lot of gynosperms, (because they are dominated by spurce trees)
–> Majour source of lumber)
characterstics of gymnosperms + charactersitics of cones
—> Due to size,
ussally have large, shallow root systems (that spread horizontall out near the soil surface)
—> These roots form a mycorrhizal relationship with fungi
(Fungi help plant absorb nutrients)
(Plant provides fungi with surgars)
-> Seeds that gynosperms produce are called cones (the reproductive structure of conifers)
–> 2 types of cones
male cones produce pollen (pollen is the grain that contains the male gamates))
female cones produce ovules (eggs)
—-> When comes fertlize (come into contact) they devolpe into a seed.
–> Produce naked seeds (ovules are not enclosed by an ovary)
–>Therefore when pollem reaches the female cone, containing the egg, it becomes fertlized
These seeds are NAKED, not enclosed in a ovary or a fruit.
Gynmnosperms are mostly WOODY
Why are vascular tissues important/why did plants evolve to have vascular tissues?
Consists of xylem and phloem, specalized for transportation of water and nutrients. Allowed the plant to grow taller + more efficient in transportation.
General charactertistics of angiosperms?
Largest group of living plants
Reproductive structure is flower
Flowers contain pollen and ovaries (eggs)
—> Same function as cones, however female eggs are encompassed by a enclosed ovary
After fertilization, seeds form within the ovary
Outer tissues of ovary become fruit (fruit offers protection)
The main function of the fruit is to help disperse the seeds
What are the two types of seeds in angiosperms?
Monocotyledons (1) or Diocotyledons (2 seeds)
Cotyledons refer to structures that store food used by the growing embryo (within the seed)
Angiosperms: how do i know if its monocot or dicot?
—? In reference to seeds, roots, vascular system, leaves, and flowers.
Seed: mono = 1 cotylydon, di = 2 cotyledon
Root: mono = fibrous root, di = tap root
Vascular: mono= scattered xylem and phloem, di = ringed zylem and phloem (ringed trees)
leaf: mono = parallel veins (long leafs), di = net-like veins (look like a net)
Flower: Mono = multiples of 3/3 petals, dicot = 4 or 5 petals.
Asexual reproduction within seeded plants (how does it work and named/methods)
Seeds refer to a sexual process (because male gamates must fertlize female gamates to produce seeds)
–>Therefore plants can also produce asexually via
Mitosis: creation of clones (genertically identical offspring from its diploid cells)
–> Vegetative reproduction
Rhizomes: Horizontal underground stems that grow below the soil surface
–> Spread laterally and produce roots and shoots at the nodes of the plant (these form new plants)
Seen in: ginger, iris, etc
Stolons:
–> Horizontal stems that grow along the surface of soil
–> Extend outwards from the parent plant, and at the nodes, stolons form roots and shoots that create new plants
ie: strawberries.
Croms: short, vertical, swollen underground stems
–>Buds on the surface of a crom devolpe into new roots and shoots, while the chrom stores nutrients to support the new plant growth
“Eyes” on tubers (potatoes)
Fragmentation (piece breaks off and then begins making a new plant)
Grafting: two plants join together to grow as a single plant
Growing from cuttings. (cut a plant, place in water and it grows as a new plant)
Benefits of asexual reproduction in plants.
All successful offspring is identical
No need to waste energy on flowers
(Seed dispersal, etc)
No need to depend on presence of other individual or pollinator
Self dependent)
High plantlet survival rate (robust)
–>Usually health and strong
How do seeds work?
Seeds protect and carry embryo to new location
Dispersed by wind or animal that eats the seeds
Endosperm: nutritive tissue in an angiosperm seed (middle)
—> How is the seed made? Ovule becomes seed (embryo + endosperm) (Fertlizing the egg)
Seed coat: protects seed (outwer protection)
Cotyledon: nutrient storage (inner)
Embryo (the very center)
what does germination mean?
The process by which an organism grows from a seed or spore.
How does sexual reproduction in gymnosperms happen? (alterations of generations) (specifically for plants with cones)
Diploid stage (Asexual stage):
Seed (diploid) grows into a mature sporophyte, which produces two types of cones (female and male), these cones are haploids.
—> contain the gametes, not the gamete itself
male cone = microspore
female cone = megascore
The products of cones come into contact (fertlization) and produce the zygote, which is a seed.
Sporophyte (Tree) → Cones (Male & Female)
Cones → Microspores (Male, Pollen Grains) & Megaspores (Female, Ovules)
Microspores → Male Gametophyte (Pollen Grain) PRODUCED THROUGH MEIOSIS
Megaspores → Female Gametophyte (Eggs in Ovules)
PRODUCED THROUGH MEIOSIS
Pollination → Fertilization (Zygote)
Zygote → Seed Formation → Seed Dispersal → Germination
Seed → Sporophyte (Tree)
Sexual reproduction in angiosperms: understandging the structure of a flower.
Pollination happens by wind or by animals (carrying the pollen from one plant to another)
The anthre of the plant produces the pollen (nubs)
Filament: supports the anther (stem-liek structure holding the nubs)
Stigma: the middle part of the plant (large stem-like structure), it is a sticky surface on top of the style, and catches the pollen
Style: is the stem like structure called a stalk, that leads to the ovaries.
How does an angiosperm reproduce? (Alterations of generations)
Zygote matures into a sporophyte which creates the flower, the flower goes through meiosis and produces gamates.
–> Female gamate (ovule)
–> Male gamate is the anther/pollen
–>Gamates go through mitosis (to get bigger), and then come into contact creating another zygote.
Sporophyte (Flowering Plant) → Flowers (Male & Female Structures)
Flowers → contain Microspores (Pollen) & Megaspores (Ovules)
Microspores → Male Gametophyte (Pollen Grain) PRODUCED VIA MEIOSIS
Megaspores → Female Gametophyte (Egg in Ovule)PRODUCED VIA MEIOSIS
Pollination → Fertilization (Zygote + Endosperm)
Zygote → Seed Formation → Fruit Formation → Seed Dispersal
Seed → Sporophyte (Flowering Plant)
2 types of pollinations:
Some plants can self-pollinate: pollen meets ovary on the same plant
Cross-pollination: pollen meets ovary of a different plant
How does pollinations and fertilization relate?
-Pollinations refers to the transger of pollen from one anther to a stigma (male gamate in a pollen grain pentrates an ovule containg a female gametophyte), while fertilization is the fusion of male and female gametes
How do you fertilize a plant?
Two sperm nuclei (in the haploid stage, male produces many microspores) meet ovule
One sperm unites with egg to form diploid zygote
Other sperm fuses with two polar nuclei in the ovule forming a triploid (3n) cell that develops into endosperm
—>Endosperm is inside the seed, and it serves as nutrion for the embryo
Fruit: mature ovary of an angiosperm, contains seeds
What are the benefits of speed plants? / sexual reproduction within seeded plants?
High genetic diversity
More sustainable
Seeds can be dispersed far away from parent plant
Increases plantlet success (less competition for resources/better growing conditions)
Seeds can be dormant for long periods until conditions are good for growth (increasing chance of survival)
How do humans affect the diversity of plants?
Climate change
Overharvesting
Pollution (interferes
with photosynthesis in
some plants)
Are plants the most dominate organisms? (Specific?)
Plants are the most dominate
Specifically angiosperms
How have plants evolved? (What have they evolved from?)
Charophytes (A protist group)
Similarities between plants and protists? (Specifically what type of protist)
Charophytes.
—Both plants and charophytes have…
- Chlorophyll
-Cell walls composed of cellulose
-At the end of mitosis, both begin cytokinesis by forming a cell plate
-Both store excess food as starch
What are resurrection plants?
Ground of plants that can survive extreme dyhydration for extended periods of time and then come back to life.
“Write themselves into a dormant state” when there is no water.
How do bryophytes reproduce?
Exhibit alterations of generations, reproducing asexually and sexually.
Gamtephyte (haploid stage) produces gamates that have siwmmign structures
For fertilization to occur, bryophytes require water.
Fertilization = zygote
Zygote devolpes into a sporophyte which remains attached and dependent to the gametophyte for nutrients
Sporophyte foes through meiosis, which produces haploid spores.
These spores are disperse through wind or water, and germinate under suitable conditions to form a new gametophyte.
Why are vascular plants better than non-vascular plants?
Plants with specialized tbes for transportantions can grow to taller heights (because the leaves and roots are able to receive nutrients), therefore they can acess more sunlight.
Whats the differences between lycophytes + pterophytes and bryophytes?
-Specifically with their gamates and mode of nutriention
Lycophytes + pterophytes are larger and grow higher above ground
The sporophytes of lycophytes and pterophytes are photosynthetic, while the borophytes sporophyte epends on its gametophyte.
Why are seeded plants more dominate than plants that produce spores?
Seeded plants are not restricted to the reproduction over short distances in wet cpndotopms.
They are activtly being carried over by wind or animals instead of travelling through water.
Whats a seed’s sturcture?
Seed coat for protection, embryo (called the embroy sporophyte), and the nutriention for the seed.
–> The nutrient supplies the embryo with nutrients before it is able to rely on photosunthesis.
