plant classification and reproduction: lesson 9B

Question 1

importance of plants in reference to the environment and humans:

Answer 1

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

Question 2

What are the general characteristics of a plant?

Answer 2

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)

Question 3

What is alterations of generations and what are its 2 life cycles?

Answer 3

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.

Question 4

Whats the difference between animal life cycles and a plants life cycles?

Answer 4

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

Question 5

Alterations of generations: Plant life cycle, how does it work?

Answer 5

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.

Question 6

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?)

Answer 6

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)

Question 7

Flow chart on how to classfy plants

Answer 7

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?

Question 8

What does sporophyte refer to? (in the alterations of generations)

Answer 8

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

Question 9

What does the gametophyte refer to? In alterations of generations?

Answer 9

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

Question 10

Non-vascular plants are called what? and what are their characteristics?

Answer 10

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)

Question 11

VASCULAR PLANTS THAT PRODUCE SPORES:

Are called what?

Answer 11

Lycophytes (club mosses) and pterphytes (ferns)

Question 12

Chatactersitics of Lycophytes and pterophytes and why are they called different things

Answer 12

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

Question 13

If the plant is vascular? What is it called?

Answer 13

Tracheophytes

Question 14

If the plant is vascular and produces seeds what are the two names? (why are they named seperate things/reasoning)?

Answer 14

Gymnosperms (seeds in the form of a cone, therefore “naked”)

Angiosperms (Seeds in the form of a fruit, usually from flowering plants “enclosed”)

Question 15

What do gymnosperms and angiosperms both have in common?

Answer 15

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

Question 16

How do i know if a plant is a gymnosperm?

Answer 16

—> 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)

Question 17

characterstics of gymnosperms + charactersitics of cones

Answer 17

—> 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

Question 18

Why are vascular tissues important/why did plants evolve to have vascular tissues?

Answer 18

Consists of xylem and phloem, specalized for transportation of water and nutrients. Allowed the plant to grow taller + more efficient in transportation.

Question 19

General charactertistics of angiosperms?

Answer 19

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

Question 20

What are the two types of seeds in angiosperms?

Answer 20

Monocotyledons (1) or Diocotyledons (2 seeds)

Cotyledons refer to structures that store food used by the growing embryo (within the seed)

Question 21

Angiosperms: how do i know if its monocot or dicot?

—? In reference to seeds, roots, vascular system, leaves, and flowers.

Answer 21

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.

Question 22

Asexual reproduction within seeded plants (how does it work and named/methods)

Answer 22

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)

Question 23

Benefits of asexual reproduction in plants.

Answer 23

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

Question 24

How do seeds work?

Answer 24

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)

Question 25

what does germination mean?

Answer 25

The process by which an organism grows from a seed or spore.

Question 26

How does sexual reproduction in gymnosperms happen? (alterations of generations) (specifically for plants with cones)

Answer 26

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)

Question 27

Sexual reproduction in angiosperms: understandging the structure of a flower.

Answer 27

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.

Question 28

How does an angiosperm reproduce? (Alterations of generations)

Answer 28

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)

Question 29

2 types of pollinations:

Answer 29

Some plants can self-pollinate: pollen meets ovary on the same plant
Cross-pollination: pollen meets ovary of a different plant

Question 30

How does pollinations and fertilization relate?

Answer 30

-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

Question 31

How do you fertilize a plant?

Answer 31

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

Question 32

What are the benefits of speed plants? / sexual reproduction within seeded plants?

Answer 32

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)

Question 33

How do humans affect the diversity of plants?

Answer 33

Climate change

Overharvesting

Pollution (interferes
with photosynthesis in
some plants)

Question 34

Are plants the most dominate organisms? (Specific?)

Answer 34

Plants are the most dominate

Specifically angiosperms

Question 35

How have plants evolved? (What have they evolved from?)

Answer 35

Charophytes (A protist group)

Question 36

Similarities between plants and protists? (Specifically what type of protist)

Answer 36

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

Question 37

What are resurrection plants?

Answer 37

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.

Question 38

How do bryophytes reproduce?

Answer 38

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.

Question 39

Why are vascular plants better than non-vascular plants?

Answer 39

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.

Question 40

Whats the differences between lycophytes + pterophytes and bryophytes?
-Specifically with their gamates and mode of nutriention

Answer 40

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.

Question 41

Why are seeded plants more dominate than plants that produce spores?

Answer 41

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.

Question 42

Whats a seed’s sturcture?

Answer 42

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.