Ch.29 - Plant Diversity I

Question 1

Plants evolved from a green algae ancestor, but have some important differences, especially relating to the ____________ in their lifecycle.

Answer 1

Plants evolved from a green algae ancestor, but have some important differences, especially relating to the alternation of generations in their lifecycle.

Question 2

Bryophytes are __________ (non/vascular) plants which have clearly observable _____________ (gametophytes/sporophytes).

Answer 2

Bryophytes are nonvascular plants which have clearly observable gametophytes.

Question 3

Vascular plants have many adaptations and more visible ___________ (sporo/gametophytes).

Answer 3

Vascular plants have many adaptations and more visible (dominant) sporophytes.

Question 4

Around ____ million years ago, small plants, fungi, and animals emerged on land. Since colonizing land, plants have diversified into roughly _____ (#) living species.

Answer 4

Around 500 million years ago, small plants, fungi, and animals emerged on land. Since colonizing land, plants have diversified into roughly 290k living species.

Question 5

T/F: Land plants are defined as having terrestrial ancestors, even though some are now aquatic.

Answer 5

True

Land plants are defined as having terrestrial ancestors, even though some are now aquatic.

Question 6

T/F: Land plants include photosynthetic protists (algae)

Answer 6

False

Land plants do NOT include photosynthetic protists (algae)

Question 7

What are some key characteristics of terrestrial plants?

Answer 7

Key characteristics of terrestrial plants:

• Multicellular
• Eukaryotic
• Photosynthetic autotrophs
• Cell walls made of cellulose
• Chloroplasts w chlorophyll a and b

Note that many protists share these traits, incl brown, red, and green algae.

Question 8

________ are the closest relative to terrestrial plants.

Answer 8

Charophytes (type of green algae) are the closest relative to terrestrial plants.

Question 9

Plants and Charophyte green algae share which key characteristics?

Answer 9

Plants and Charophyte green algae share key characteristics:

• Rings of cellulose-synthesizing proteins
• Structure of the sperm: flagella present
• Formation of a phragmoplast: group of microtubules that form between daughter nuclei of the dividing cell

Question 10

Many species of charophytes live in shallow waters. What adaptation allowed plants to survive dry periods on land?

Answer 10

Sporopollenin – durable polymer that prevents zygotes from drying out

Question 11

Which derived traits of plants are found in the embryophyte kingdom Plantae but not in charophytes?

Answer 11

• Alternation of generations
• Multicellular dep embryos.
• Production of walled spores in sporangia
• Multicellular gametangia
• Apical meristems

Plants also have mycorrhizae–symbiotic associations b/w fungi/plants; cuticle, a waxy covering of the epidermis; and stomata, specialized cells that allow for gas exchange between the outside air and the plant.

Question 12

Bryophyta (seedless, non-vascular plants) include which three phyla?

Answer 12

Bryophyta (seedless, non-vascular plants) include Hepatophyta (liverworts), Bryophyta (Mosses), and Anthocerophyta (hornworts).

Question 13

Seedless vascular plants incl wh two phyla?

Answer 13

Seedless vascular plants:

• Phylum Lycophyta (lycophytes)
• Phylum monilophyta (monilophytes)

Question 14

Vascular seed plants incl gymnosperms and angiosperms. Which phyla are included in gymnosperms? Angiosperms?

Answer 14

Gymnosperms (vascular seed plants):

• ginkgophyta
• cycadophyta
• gnetophyta
• coniferphyta

Angiosperms:

• Anthophyta (flowering plants)

Question 15

What is meant by alternation of generations?

Answer 15

Lifecycle of all plants alternate between gametophyte (haploid) and sporophyte (diploid) forms; not found in charophytes.

• Gametophyte generation is haploid and produces haploid gametes by mitosis
• Fusion of a sperm and egg gives rise to the diploid sporophyte, wh produces haploid spores by meiosis
• Spores develop into gametophytes

Question 16

What are sporophytes?

Answer 16

Sporophyte: “spore producing plant”

• diploid zygote grows, dividing by mitosis, produces sporophyte
• Sporophyte undergoes meiosis to produce spores
  
  • Reproductive cells that develop into haploid organisms (the gametophyte)

Question 17

The diploid zygote grows, dividing by ______ (mitosis/meiosis), to produce a sporophyte. The sporophyte undergoes ______ (mitosis/meiosis) to produce spores.

Answer 17

The diploid zygote grows, dividing by mitosis, to produce a sporophyte. The sporophyte undergoes meiosis to produce spores.

Question 18

T/F: In seedless plants, both gametophytes and sporophytes are visible, while in flowering (seed) plants only the sporophytes are visible.

Answer 18

True

In seedless plants: both gametophytes and sporophytes are visible, but look very different

In flowering plants: only the sporophytes are visible; gametes are microscopic

Question 19

Dev of the embryo (fr the zygote) occurs in the tissues of the _______________.

Answer 19

Dev of the embryo (fr the zygote) occurs in the tissues of the female gametophyte.

• Specialized placental transfer cells enhance transfer of nutrients.
• Landplants referred to as embryophytes bc of this derived trait (multicell, dep embryos).

Question 20

Landplants referred to as embryophytes bc of wh derived trait?

Answer 20

Multicellular, dependent embryos

Question 21

The sporophyte produces spores in organs called _________.

Answer 21

The sporophyte produces spores in organs called sporangia.

Question 22

Diploid cells called _________ undergo meiosis to generate haploid spores.

Answer 22

Diploid cells called sporocytes undergo meiosis to generate haploid spores.

Question 23

________ (hap/diploid) cells called sporocytes undergo meiosis to generate ________ (hap/diploid) spores.

Answer 23

Diploid cells called sporocytes undergo meiosis to generate haploid spores.

Question 24

What advantage does sporopollenin offer?

Answer 24

Spore walls contain sporopollenin, which makes them resistant to harsh environments

Question 25

Summarize the diffs b/w spores, sporangia, and sporocytes

Answer 25

Spores – haploid reproductive cells Sporangia – multi-cellular organs that produce spores Sporocytes – diploid cells that undergo meiosis to produce spores

Question 26

What are gametangia?

Answer 26

Gametangia are **organs** found in gametophytes where the production of gametes occurs

Question 27

Archegonia are female gametangia while antheridia are male gametangia. Summarize the diffs.

Answer 27

**Archegonia** – female gametangia * pear-shaped organ that produces a *single* egg **Antheridia** – male gametangia * Produce sperm, *many* wh have flagella to swim to archegonium.

Question 28

What are apical meristems?

Answer 28

Apical meristems * Found at the tips of roots and shoots * Regions where cell division occurs * Differentiation of cells leads to specialized tissues

Question 29

Define the following terms and their relationship to each other: sporophyte, sporangia, sporocytes, spores.

Answer 29

Spores – haploid reproductive cells Sporangia – multi-cellular organs that produce spores Sporocytes – diploid cells that undergo meiosis to produce spores Sporophyte - diploid, dominant form of vascular plants The gametophyte generation is haploid and produces haploid gametes by mitosis. Fusion of a sperm/egg gives rise to diploid sporophyte, wh produces haploid spores by meiosis. Spores dev into gametophytes.

Question 30

Define the following terms and their relationship to each other: gametophyte, gametangia, archegonia, antheridia.

Answer 30

**Gametangia** are organs found in gametophytes where the production of gametes occurs. * **Archegonia** - female gametangia; produces ONE egg. * **Antheridia** - male gametangia; produces many sperm. The gametophyte generation is haploid and produces haploid gametes by mitosis. Fusion of a sperm/egg gives rise to diploid sporophyte, wh produces haploid spores by meiosis. Spores dev into gametophytes.

Question 31

Name the three phyla of non-vascular plants (bryophytes).

Answer 31

Phylum Hepatophyta – Liverworts (9,000) Phylum Anthocerophyta – Hornworts (100) Phylum Bryophyta – Mosses (15,000)

Question 32

What are several key characteristics of non-vascular plants (bryophytes)?

Answer 32

**Lack true roots and stems** **Gametophyte dominates lifecycle**; larger and longer lived **Herbaceous** = non-woody (wort = herb in Anglo-Saxon) Likely resemble v early plants; fossilized tissue similar to liverworts.

Question 33

T/F: Bryophyte gametophytes are larger and longer-lived than sporophytes.

Answer 33

True In bryophytes, gametophyte is the dominant stage. Spores grow into gametophytes in damp environments (soil, tree bark)

Question 34

\_\_\_\_\_\_\_\_ are one-cell thick filaments that help with water absorption \_\_\_\_\_\_\_\_ are structures that produce gametes

Answer 34

**Protonema** – one-cell thick filaments that help with water absorption **Gametophore** – structure that produces gametes

Question 35

Bryophyte sporophytes grow out of \_\_\_\_\_\_\_\_\_\_, and are the smallest and simplest sporophytes of all extant plant groups

Answer 35

Bryophyte sporophytes grow out of **archegonia**, and are the smallest and simplest sporophytes of all extant plant groups

Question 36

A sporophyte consists of a foot, a ____ (stalk), and a sporangium, also called a \_\_\_\_\_\_\_, wh discharges spores through a \_\_\_\_\_\_\_\_.

Answer 36

A sporophyte consists of a foot, a **seta** (stalk), and a sporangium, also called a **capsule**, which discharges spores through a **peristome.**

Question 37

T/F: Hornwort and moss sporophytes have stomata for gas exchange; liverworts do not.

Answer 37

True Hornwort and moss sporophytes have **stomata** for gas exchange; liverworts do not.

Question 38

Label the attached diagram for plant taxonomy.

Answer 38

Question 39

Vascular plants are divided by whether or not they produce seed. What are the two phyla of *seedless* vascular plants?

Answer 39

Two phyla of *seedless* vascular plants Phylum **Lycophyta** (1,200) * E.g. mosses * Think: "lyco moss, lyco boss" Phylum **Monilophyte** (12,000) * E.g. ferns * Prev. **Pterophyta** Seed plants: gymnosperm and angiosperm (flowering)

Question 40

Origins and Traits of Vascular Plants: * Fossils of the forerunners of vascular plants date back about **\_\_\_\_** million years. * These early tiny plants had indep, branching **\_\_\_\_\_\_\_**. * Dominant land cover ~**\_\_\_\_** myo (**\_\_\_\_\_\_\_\_** and **\_\_\_\_\_\_\_\_\_** periods).

Answer 40

Origins and Traits of Vascular Plants: * Fossils of the forerunners of vascular plants date back about **425** million years. * These early tiny plants had indep, branching **sporophytes**. * Dominant land cover ~**420** myo (**Devonian** and **Carboniferous** periods).

Question 41

Seedless vascular plants are mostly found in ______ (arid/damp) environments.

Answer 41

Seedless vascular plants are mostly found in **damp** environments. * Recall: lycophytes and monilophytes. Need damp environ bc sperm must SWIM to eggs in archegonia of another gametophyte.

Question 42

T/F: Sporophytes of seedless vascular plants are branched and are NOT dep on gametophytes for nutrition.

Answer 42

True Sporophytes of seedless vascular plants are branched and are NOT dep on gametophytes for nutrition. * More complex morphologies * Grow taller, compete for sunlight

Question 43

Living vascular plants are characterized by: * Vascular tissues called **\_\_\_\_\_\_** and **\_\_\_\_\_\_** * Well-developed **\_\_\_\_\_** and **\_\_\_\_\_\_** * Life cycles with dominant **\_\_\_\_\_\_\_\_\_**

Answer 43

Living vascular plants are characterized by: * Vascular tissues called **xylem** and **phloem** * Well-developed **roots** and **leaves** * Life cycles with dominant **sporophytes**

Question 44

In seedless vascular plants, ______ conducts most of the water and minerals and includes dead cells called \_\_\_\_\_\_\_.

Answer 44

In seedless vascular plants, **xylem** conducts most of the water and minerals and includes dead cells called **tracheids**.

Question 45

In seedless vascular plants, ______ consists of living cells and distributes sugars, AAs, and other organic products.

Answer 45

In seedless vascular plants, **p****hloem** consists of living cells and distributes sugars, AAs, and other organic products.

Question 46

What advantages do roots and leaves offer vascular plants?

Answer 46

Roots – Anchor plants; enable absorption of water and nutrients from the soil. Leaves – Increase surface area; capturing more solar energy for psynth. * Both cases, allows plant to grow taller, compete for sunlight, and disperse spores further. * Lead to forests due to SELECTION for taller plants.

Question 47

Describe the two types of leaves.

Answer 47

**Sporophylls** - modified leaves bearing sporangia * **Microphylls** - leaves w a single vein * **Megaphylls** - leaves w a highly branched vascular system

Question 48

**\_\_\_\_\_\_\_\_\_** are modified leaves that bear sporangia. **\_\_\_\_\_** are clusters on the undersides of sporophylls. **\_\_\_\_\_\_\_\_** are sporophylls forming cone-like structures.

Answer 48

**Sporophylls** are modified leaves that bear sporangia. **Sori** are clusters on the undersides of sporophylls. **Strobili** are sporophylls forming cone-like structures.

Question 49

How do sporophytes of vascular plants compare to bryophytes?

Answer 49

**In contrast w bryophytes, sporophytes are the larger generation in seedless vascular plants**. Gametophytes are tiny plants that grow on or below the soil surface

Question 50

T/F: most seedless vascular plants are heterosporous.

Answer 50

False Most seedless vascular plants are **homosporous**. * Produce ONE type of spore. * Produce **bisexual gametophyte** that produces **both** eggs and sperm.

Question 51

T/F: some seedless vascular plants are heterosporous.

Answer 51

True SOME seedless vascular plants are heterosporous. (ALL seed plants are heterosporous) Heterosporous: TWO types of sporangia → produce two type of spores: * **Megasporangia** produce megaspores that dev into **female** gametophytes, wh will produce eggs. * **Microsporangia** produce microspores that dev into **male** gametophytes, wh will produce sperm.

Question 52

What is the diff b/w mega and microsporangia?

Answer 52

Megasporangia produce megaspores that dev into female gametophytes, wh will produce eggs. Microsporangia produce microspores that dev into male gametophytes, wh will produce sperm.

Question 53

Assort the following in Phylum Lycophyta or Monilophyta (formerly Pterophyta): * club mosses * ferns * whisk ferns * spike mosses * quillworts * horsetails

Answer 53

Phylum Lycophyta: club mosses, spike mosses, quillworts * Lyco moss, like a boss Phylum Monilophyta (formerly Pterophyta): ferns, horsetails, whisk ferns and their relatives

Question 54

Summarize the significance of seedless vascular plants.

Answer 54

Grew to great heights during Devonian early Carboniferous → **first forests**. * Early forests helped signif **↓ CO2** → global cooling → widespread **glacier** formation. * **Roots of vascular plants also ↓ CO2**: roots secrete acids that break down rocks → ↑ rate of Ca/Mg liberation fr rocks into soil → rxn w CO2 dissolved in rain water → compounds wash into ocean → incorporated into Ca/Mg carbonate. Seedless vascular plants that formed first forests eventually became **coal** → ↓ CO2 (in atmos). * Carboniferous swamps → dead bodies of early trees did not completely decay → thick layers of peat → heat/pressure converted peat to coal.

Question 55

Fern gametophytes are \_\_\_\_\_\_\_\_\_\_. * produced from haploid gametes * free-living, multicellular organisms * part of the asexual life cycle * found on the underside of fern leaves (fronds) * photosynthetic diploid organisms

Answer 55

Fern gametophytes are \_\_\_\_\_\_\_\_\_\_. * produced from haploid gametes * **free-living, multicellular organisms** * part of the asexual life cycle * found on the underside of fern leaves (fronds) * photosynthetic diploid organisms Ferns (monilophytes; non-vascular) produce small heart-shaped gametophytes that sustain themselves by psynth and produce haploid gametes. Most fern species are **homosporous** -\> devs into **bisexual** psynthc gametophyte -\> EACH gametophyte devs antheridia AND archegonia. Gametophytes are **haploid**. Gametophytes produce gametes. Gametophytes are involved in **sexual** reproduction. The underside of the leaf (frond) is where **sori** are found.

Question 56

Water is brought into mosses primarily by \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_.

Answer 56

Water is brought into mosses primarily by **diffusion through all cells**. * Mosses lack true leaves/roots. * Bryophyte gametophytes are anchored by delicate **rhizoids**, which are long, tubular single cells (in liverworts and hornworts) or filaments of cells (in mosses). * Unlike roots, rhizoids lack specialized conducting cells and do not play a primary role in water and mineral absorption.

Question 57

T/F: The gametophyte stage of the plant life cycle is most conspicuous in mosses.

Answer 57

True Mosses have a dominant gametophyte. * Unlike vascular plants, in all three bryophyte phyla the haploid gametophytes are the dominant stage of the life cycle. * I.e. typ larger and longer-living than the sporophytes. * When bryophyte spores are dispersed to a favorable habitat, such as moist soil or tree bark, they may germinate and grow into gametophytes. * **The sporophyte is the dominant stage in ferns (monilo),** **club mosses (lyco), and seed plants (gymno & angio)**.

Question 58

Which trait was most important in enabling the first plants to move onto land?

Answer 58

Dev of sporopollenin to prevent the desiccation of zygotes. * w/o sporopollenin, plant reprod on land would have been much more difficult.

Question 59

The diploid generation of the plant life cycle always \_\_\_\_\_. * produces eggs and sperm * produces spores * is larger and more conspicuous than the haploid stage * develops from a spore * is called the gametophyte

Answer 59

The diploid generation of the plant life cycle always \_\_\_\_\_. * produces eggs and sperm * **produces spores** * is larger and more conspicuous than the haploid stage * develops from a spore * is called the gametophyte

Question 60

In seedless plants, a fertilized egg will develop into \_\_\_\_\_\_\_\_\_\_. * a gametophyte * a sporophyte * spores * a fruit * gametes

Answer 60

In seedless plants, a fertilized egg will develop into \_\_\_\_\_\_\_\_\_\_. * a gametophyte * **a sporophyte** * **Releases haploid spores.** * spores * a fruit * gametes

Question 61

Most bryophytes, such as mosses, differ from all other plants in that they \_\_\_\_\_. * lack true leaves and roots * produce spores * do not produce flowers * have cones but no seeds * have flagellated sperm

Answer 61

Most bryophytes, such as mosses, differ from all other plants in that they \_\_\_\_\_. * **lack true leaves and roots** * **Have rhizoids instead.** * produce spores * do not produce flowers * have cones but no seeds * have flagellated sperm

Question 62

In contrast to bryophytes, in vascular plants the dominant stage of the life cycle is the\_\_\_\_\_\_\_\_. * gametophyte * archegonium * spore * sporophyte * antheridium

Answer 62

In contrast to bryophytes, in vascular plants the dominant stage of the life cycle is the\_\_\_\_\_\_\_\_. * gametophyte * archegonium * spore * **sporophyte** * antheridium

Question 63

What evolutionary development allowed plants to grow tall? * rhizoids * sporophylls * the waxy cuticle * leaves * lignified vascular tissue

Answer 63

What evolutionary development allowed plants to grow tall? * rhizoids * sporophylls * the waxy cuticle * leaves * **lignified vascular tissue**

Question 64

During the Carboniferous period, forests consisting mainly of _____ produced vast quantities of organic matter, which was buried and later became coal. * early angiosperms * gymnosperms and early angiosperms * gymnosperms * giant mosses * ferns and other seedless plants.

Answer 64

During the Carboniferous period, forests consisting mainly of _____ produced vast quantities of organic matter, which was buried and later became coal. * early angiosperms * gymnosperms and early angiosperms * gymnosperms * giant mosses * **ferns and other seedless plants.**