Chapter 25- Plant Evolution and Diversification

How can fruits be adapted?

Fruits may be adapted to attract animals to eat them, for wind dispersal, to attach to animal fur, or to float in water

What is the major difference b/w eudicots and monocots?

Monocots consist of 1 cotyledon and eudicots consist of 2 cotyledons

What three major classes of SM are there?

Terpenes and terpenoids, phenolics, alkaloids

7. Ginkgos

seed plants, more diverse in the past

1. Liverworts

useful model of the earliest land plants

When can vascular plants grow larger?

- In relatively dry habitats, vascular plants are able to grow to larger sizes and remain metabolically active for longer than bryophytes because they can better maintain stable internal water content

Lycophytes and Pteridophytes are vascular plants that do not produce seeds

-Lycophytes are the oldest phylum of living vascular plants -Pteridophytes are the second oldest living plant phylum --Lycophytes diverse in past; now~1000 living species --Pteridophytes ~12000 modern species including horsetails, whisk ferns, and other ferns -these are known as the seedless vascular plants

Modern Land Plants Can Be Classified into Nine Phyla:

-Plant systematics use molecular and structura; information to classify plants; modern phyla are informally described as: --Liverworsts, mosses, hornworts, Lycophyte, pteriodophytes, cycads, ginkgos, conifers, and flowering plants

Gymnosperms and Angiosperms- Seed producing plants

-Seeds: complex structure with tissues that protectively enclose embryos and contain stores of carbohydrate, lipid, and protein, that enable embryos to grow to develop --seed plants produce pollen, small spores that contain and protect microscopic male gametophytes -phyla typically known as gymnosperms(cycads, ginkgo, conifers)("naked seeds"; lack flowers, fruits and endosperm) -Angiosperms produce seeds and pollen as well as flowers, fruits, and endosperms(nutritive seed tissue)

Cont'd:

-bryophytes are unable to grow tall because conducting tissues are not tough enough to also provide structural support -require moist habitats to accomplish sexual reproduction b/c they produce flagellate sperm which swims though water to fertilize egg. -have dominant (larger and longer-lived) gametophyte generation; sporophyte is relatively small and short -lived -moss genus Mnium -life cycle of the early-diverging peat moss genus Sphagnum

9. Flowering Plants

-currently dominant group, humans and many other animals depend heavily on these plants

Land plants

-distinguished form closely related algae by the presence of terrestrial adaptations -plants and closest green algal relative are known as streptophytes

Cycads

-earliest-diverging modern gymnosperms phylum, originated more than 300 mya -cycads are listed as endangered --spreading, palm-like leaves, produce conspicuous cone-like structure that produce either pollen or ovules --beetles are pollinators

Cont'd:

-embryos are young, multicellular sporophytes --embryos follow fertilization of an egg and depend on maternal tissue for food during development --embryo are not resent in related green algae; they are a foundational feature of land plants(embryophytes) -tough-walled spores allow plants to disperse offspring through dry air -Gametangia(specialized structures): generate, protect, and disperse land plant gametes. -Sporangia(specialized structures): produce, protect, and disperse spores of land plants

In what ways has flower evolution change the way that they foster the transfer of pollen from one plant to another?

-flowers have fused petals that form floral tubes: tend to accumulate nectar which attracts pollinators. -many plants produce inflorescences; groups flowers tightly which allow pollinators to transfer pollen among large number of flowers at the same time -Grasses feature flowers with few to no perianths, which foster pollination by wind.

Lycophytes and Pteridophytes- seedless vascular plants

-have a life cycle dominated by by the diploid sporophyte, large enough to produce many spores -life cycle of a typical fern is depicted

What kind of distinctive feature to land plants possess?

-land plants display features that represent early adaptations to the land habitat -bodies primarily composed of tissues --compared to algae they have less surface which decreases water loss to air -tissue arise from apical meristems at growing tips --able to produce thick robust bodies to withstand stress or droughts --able to produce tissues and organs with specialized functions

Cont'd:

-life cycle involves alteration of generations --haploid gen. (gametophyte): produces eggs and/or sperm in mitosis --diploid gen. (sporophyte): produces spores by meiosis LEARN GRAPH ON BOOK AND SLIDES***

Where does the name conifers derive from?

-lineage named for their seed cones; modern conifer families include more than 50 genera

Mosses, Liverworts, and Hornworts are the simplest land plants

-liverworts, mosses, and hornworts are informally known as the bryophytes --The bryophytes do not clade; individual groups form monophyletic phylum --however these groups share common structural, reproductive, and ecological structures. --~6,500 modern liverworts, ~12,000 mosses, and ~100 hornworts -bryophytes are relatively small and are most common in moist habitats

Parts of the plant body:

-lycophytes, pteridophytes, and other vascular plants generally possess stems, roots, and leaves having vascular systems composed of conductive phloem and xylem

Vascular plants-cont'd

-maintain stable internal water content because of several adaptations, including a vascular system, waxy cuticle, and stomata --vascular systems allows water, minerals, and sugars to move to appropriate places. --waxy cuticle: prevents drying and deters pathogens --stomata: pores that can open and close on the surface tissue of vascular plant stems ---allows for exchange of o2 and co2 while conserving water

Where are conifers most commonly seen?

-most common in cold, dry climates (mountain and high-altitude forests)

Plants

-multicellular, eukaryotic organisms that are generally photosynthetic and primarily live on land. -usually classified into Kingdom Plantae

Diversity of Modern Gymnosperms

-relationship b/w seedless and seed plants are depicted in a phylogenetic -Gymnosperms have the capacity to produce wood, compose of xylem tissue --producing wood allows for plants to grow to tree height; tall height provides an advantages in capturing light energy for photosynthesis ---angiosperms inherited the ability of producing seeds and wood

Ginkgo biloba

-today may be nearly extinct in the wild -trees are widely planted along city streets because they tolerate heat, cold, and pollution better than many other trees -individuals can live for more than 1000 years

What is the product of a conifer?

Conifers produce simple pollen cones and more complex ovule-bearing cones

What is a the unique reproductive process that angiosperms have?

Double fertilization

What are two large and diverse lineages of angiosperms?

Eudicots and Monocots

Have other plants been domesticated?

In addition to grain, humans have domesticated a number of other plants( that can easily be found in the vegetables section of the grocery store)

What do Phenolics do?

Responsible for some colors and the distinctive flavors of cinnamon, nutmeg, ginger, cloves, chilies, vanilla; some are antioxidants; some absorb UV radiation

In angiosperms what are/do secondary metabolites?

Secondary metabolites are organic compounds that are not essential for basic cell structure and growth bit aid in survival, structure, and reproduction.

What parts make up to pistil (female)?

Stigma-receives and recognizes pollen Style-long middle portion ovary-encloses and protects ovules

In the confier phylum what else is included?

The Gnetales in 3 distinctive generas (gnetum, ephedra, and welwitschica)

What are the function of colorful petals?

attract pollinators

Phloem

conducts a watery sap containing organic molecules such as sugar

Xylem

conducts water and minerals throughout the body and provides structural support - -

8. Conifers

cone-bearing seed plants

What does dispersal help with?

dispersal helps prevent seedlings from competing with their larger parents for scarce resources and helps to colonize new habitats

4.Lycophytes

earliest-diverging groups of vascular plants, no seeds, were more abundant and diverse during ancient times

6. Cycads

early-diverging lineage of seed plants

What do fruits do?

favor seed dispersal

Where are flowers produced?

flowers are produced at the stem tips.

What do endosperm do?

food helps embryos within seeds grow into seedling

What do flowers do?

foster seed production

3. Hornworts

have well-developed system for internal conduction of water, minerals, and organic compounds

2. Mosses

important in stabilizing Earth's climate

5. Pteridophytes

includes many modern ferns, no seeds

What is one favorable trait produced by domestication?

larger grains, greater number of grains, and softer grains were also selected during the process of domestication

What do Alkaloids do?

often affect animal nervous system; examples include caffeine, nicotine, morphine, ephedrine, cocaine, and codeine.

What is the pistil composed of?

one or several carpels

What do Terpenes and terpenoids do?

play a protective role in the plant, helping the plant to recover from damage; others act as a part of the plant's immune system to keep away infectious germs. Some people also use the term terpenoids.

Vascular Plants:

possess a conduction system (xylem and phloem) that also provides structural support

What is domestication?

process of artificial selection, where traits that are desirable to humans are selected

what organs are typically in flowers?

sepals, petals, pollen-producing stamens, and ovule-producing stamens, and ovule-producing carpels.

What are fruits and what do they do?

structures that develop from ovary wall in diverse ways that aid the dispersal of the enclosed seeds

dominant sporophyte generation

supportive lignin-walled water-conducting tissue-xylem; specialized organic food conducting tissue-phloem; sporophyte branched and eventually become able to grow independently of gametophytes; have stems; most have leaves and roots

Why traits do angiosperms have that makes them so successful?

the evolutionary success of angiosperms is based on a combination of traits(flowers, fruits, and endosperm)

What kind of adaptations can conifers acquire to adapt to their environment?

tree shape and flexible branches- shed snow leaf shape and structure- resist drought damage when water is scarce(summer and winter) needle shaped leaves with waxy cuticle reduces water loss many are ever green-helps them start photosynthesis early