Chapter 23 Plant Evolution and Diversity - BSC 111

concept

Angiosperms produce three main groups of secondary metabolites: (1) terpenes and terpenoids; (2) phenolics; and (3) alkaloids, which play essential roles in plant structure, reproduction, and defense, respectively

double fertilization

In angiosperms, the process in which two different fertilization events occur, producing both a zygote and the first cell of a nutritive endosperm tissue

vascular tissues

Includes both xylem and phloem, plant tissue that provides both structural support and conduction of water, minerals, and organic compounds in major plant organs such as stems, roots, and leaves.

concept

Lycophytes, ferns, and other vascular plants (tracheophytes) generally possess stem, roots, and leaves having vascular systems composed of conductive phloem and xylem

fleshy fruit

adapted to attract animals that consume the fruits and excrete the seeds ex) cherry

perinath

all of a flower's sepals and petals are collectively known as this

pollinator

an animal that carries pollen between angiosperm flowers or cones of gymnosperms

Cycads

an early-diverging lineage of seed plants and so are important in understanding how seeds first evolved

Land plant tissues arise from one or more actively dividing cells that occur at growing tips, forming

apical meristems

Flowering plants (Angiosperms)

are the plants upon which humans and many other animals most depend.

Mosses

arose after liverworts, but prior to all other modern plant group Play a particularly important role in stabilizing Earth's climate

A plant produces juicy, sweet red fruits having relatively small seeds. Among the choices given, which seed dispersal agent is most likely in nature? a) butterfly b) bird c) bear d) wind e) water

b) bird

Conifers

cone-bearing seed plants, are particular important to humans as sources of wood and other commercial materials

aggregate fruit

consisting of many, tiny, single-seeded fruits produced by a single flower. allow a single animal consumer, such as a bird, to disperse many seeds at the same time ex) strawberry

Plants lack bones, but they have left many fossils. What decay-resistant plant materials are largely responsible for the occurrence of plant fossils? a) lignin in the xylem of the plant conducting system b) cutting produced on plant surfaces c) sporopollenin produced on spore surfaces d) all of the above e) none of the above

d) all of the above

What features of wild food did humans alter during crop domestication? a) fruit size b) fruit softness c) seed dispersal d) all of the above

d) all of the above

A plant produces very small, petal-less flowers that are clustered into a dangling inflorescence. Among the choices given, which pollination agent is most likely? a) butterfly b) hummingbird c) bat d) wind e) water

d) wind

juicy multiple fruit

develop when many ovaries of an inflorescence fuse together, attract large animals that can spread seeds long distances ex) pineapple

Lycophytes and ferns have a life cycle dominated by the _______________

dipolid sprophyte, which is large enough to produce many spores

inflorescences

group of flowers tightly clustered together ex) sunflower

In what way are gymnosperms different from angiosperms?

gymnosperms lack flowers, fruit, and seed endosperm

A waxy cuticle is an adaptation that

helps to prevent water loss form tracheophytes

apical meristems

in plants, a group of actively dividing cells

concept

Ancient and modern plants transformed Earth's ecology by altering atmospheric chemistry and climate, and by influencing the evolutionary diversification of animals

embryophytes

land plants

What are the modern nonvascular plants?

liverworts, mosses, and hornworts

dicots (eudicots)

one of the two largest lineages of flowering plants in which the embryo possesses two seed leaves tend to occur in fours, fives, or multiples of four and give ex) roses, daises

stigma

part of the pistil topmost part, receives and recognizes pollen of the appropriate species or genotype

streptophyte

plants and their closest green algal relatives

angiosperms

produce seeds and pollen, but are distinguished by the presence of flowers, fruits, and a specialized tissue known as endosperm

phenolic

secondary metabolite responsible for some flower and fruit colors, as well as the distinctive flavors of cinnamon, nutmeg, ginger, cloves, chilies,and vanilla. absorb ultraviolet radiation, preventing damage to cellular DNA

terpene

secondary metabolite, used in treatment of cancer, citronella, rubber, turpentine, rosin, and amber

pollen

seed plants produce these small air or animal-borne spores that contain and protect microscopic male gametophytes.

Ginkgos

seed plants that were more diverse in the past than today. Valued as hardy and attractive street trees.

Seed Plants (Spermatophytes)

seeds present; leaves have branched vein systems

gametangia

specialized structures produced by many land plants in which developing gametes are protected by by a jacket of tissue. They generate, protect, and disperse land plant gametes.

The seed plants are also known as

spermatophytes

fruits

structures that develop from flowers, enclose seeds, and foster seed dispersal in the environment

sporangia

structures that produce and disperse the spores of plants, fungi, or protists

stomata

surface pores on plant surfaces that can be closed to retain water or open to allow the entry of CO2 needed for photosynthesis and the exit of O2 and water vapor.

The simplest and most ancient phylum of modern land plants is probably

the liverworts

Plants possess a life cycle that involves alteration of two multicellular generations: the gametophyte and

the sporophyte

Streptophyte Algae

Primarily aquatic habitat; zygotic life cycle; embryos and tough-walled spores absent

Welwitschia

(part of Gnetales in conifer phylum) only one living representative, a strange looking plant that grows in the coastal Namib Deser of southwestern Africa, one of the driest places on earth. A long taproot anchors a stubby stem that barely emerges from the ground

Ephedra

(part of Gnetales in conifer phylum) tiny brown scalelike leaves and green, photosynthetic stems, these adaptations help to conserve water. produce secondary metabolites, that aid in plant structure, protection, or reproduction used to be used to treat colds and other medical conditions

Gnetum

(part of Gnetales in conifer phylum) unusual among modern gymnosperms in having broad leaves similar to those of many tropical plants. Such leaves foster light capture in the dim forest habitat. More than 30 species occur as vines, shrubs, or trees in tropical Africa or Asia.

The conifer phylum also includes the Gnetales (3)

1) Gnetum 2) Ephedra 3) Welwitschia

Land plants can be classified into nine Phyla:

1) Liverworts 2) Mosses 3) Hornworts 4) Lycophytes 5) Ferns 6) Cycads 7) Ginkgos 8) Conifers 9) Flowering plants (Angiosperms)

How have plants influenced the evolution of animals?

1) The earliest land plants generated substantial soils, thereby fostering the growth of later plants that provided earliest land animals with food and shelter 2) Plant evolutionary diversification generated many different types of habitat, thereby influencing the evolutionary diversification of animals. 3) The photosynthetic activity and fossilization of abundant Coal Age plants decreased the amount of CO2 and increased the amount of O2 in Earth's atmosphere, thereby affecting insect size and causing global climate change 4) The diversification of angiosperms following the K-T event fostered the diversification of modern mammals and other animal lineages

cuticle

A coating of wax and cutin that helps to reduce water loss from plant surfaces.

sepal

A flower organ that occurs in a whorl located outside whorls of petals of edict plants

stamen

A flower organ that produces the male gametophyte, pollen

carpel

A flower shoot organ that produces ovules that contain female gametophytes.

pistil

A flower structure that may consist of a single carpel or multiple, fused carpels and is differentiated into stigma, style, and ovary

spore

A haploid, typically single-celled reproductive structure of fungi and plants that is dispersed into the environment and is able to grow into a new fungal mycelium or plant gametophyte in a suitable habitat

Endosperm

A nutritive tissue that increases the efficiency with which food is stored and used in the seeds of flowering plants

tracehophyte stems

A plant organ that produces buds, leaves, branches, and reproductive structures.

root

A plant organ that provides anchorage in the soil and also fosters efficient uptake of water and minerals

domestication

A process that involves artificial selection of plants or animals for traits desirable to humans.

seeds

A reproductive structure having specialized tissues that enclose plant embryos; produced by gymnosperms and flowering plants, usually as the result of sexual reproduction. complex structures having specialized tissues that protectively enclose embryos and contain stores of carbohydrate, lipid, and protein that enable embryos to grow and develop

phloem

A second type of vascular tissue that conducts a watery sap containing organic molecules such as sugar through the plant body

xylem

A specialized conducting tissue in plants that transports water, minerals, and some organic compounds. Also provides structural support, allowing vascular plants to grow taller than nonvascular plants.

Tracheophytes

A term used to describe vascular plants.

lignin

A tough polymer that adds strength and decay resistance to cell walls of tracheids, vessel elements, and other cells of plants.

tracheid

A type of dead, lignified plant cell in xylem that conducts water, along with dissolved minerals; also provides structural support. Occur in specialized tissues known as xylems that conduct water and minerals through the plant.

Spermatophytes

All of the living and fossil seed plant phyla (gymnosperms and angiosperms)

Vascular plant photosynthesis transformed a very large amount of carbon dioxide into organic compounds that were incompletely degraded and transformed into coal, thereby causing a dramatic decrease in the atmospheric carbon dioxide levels during the geological period known as the

Carboniferous

concept

Cycads, ginkgos, conifers (the gymnosperms) and the flowering plants (the angiosperms) are the seed plants

Ferns

Display many modern species, particularly in tropical habitats, and are valued for horticultural plantings. Do not produce seeds, but display several adaptations that foster stable tissue-water content, a feature critical to the ability to survive through dry periods.

Nonvascular plants (Bryophytes) (liverworts, mosses, hornworts)

Dominant gametophyte generation; supportive, lignin-containing vascular tissue absent; true roots, stems, leaves absent; sporophytes unbranched and unable to grow independently of gametophytes

Vascular plants (Tracheophytes) (lycophytes, ferns, spermatophytes)

Dominant sporophyte generation; lignin-walled water-conducting tissue—xylem; specialized organic food-conducting tissue—phloem; sporophytes branched and eventually become able to grow independently of gametophytes; all have stems; most also have leaves and roots Lycophytes Leaves generally small with a single, unbranched vein (lycophylls); sporangia borne on sides of stems

Ferns + Seed Plants

Ferns Leaves relatively large with extensively branched vein system; sporangia borne on leaves; seeds absent

concept

Flower diversification involved evolutionary changes such as fusion of petals, clustering of flowers into inflorescences, and reduced perianth that improve pollination effectiveness and seed production

Gymnosperms (cycads, ginkgos, conifers)

Flowers and fruit absent; seed food stored in female gametophyte, endosperm absent

Angiosperms (flowering plants)

Flowers and fruit present; seed food stored after fertilization in endosperm formed by double fertilization

concept

Flowers foster seed production and are adapted in various ways that aid pollination. Flower parts likely evolved from leaflike structures

concept

Fruits are structures that enclose seeds and aid in their dispersal

What are the modern seed plants?

Gymnosperms and Angiosperms

concept

Humans have produced new crop species by domesticating wild plants. The process of domestication involved artificial selection for traits such as non shattering ears of wheat, corn, and rice.

vessel

In a plant, a pipeline-like file of dead, water-conducting vessel elements

ovule

In a seed plant, a megaspore-producing megasproangium and enclosing tissues known as integuments

monocots

One of the two largest lineages of flowering plants in which the embryo produces a single seed leaf. typically have petals or stamens numbering 3 or some multiple of 3 ex) tulip

concept

Paleobiologists and plant evolutionary biologists infer the history of land plants by analyzing the molecular features of modern plants and by comparing the structural features of fossil and modern plants

concept

Plants are multicellular eukaryotic organisms that are mostly photosynthetic and display many adaptations to life on land. The modern plant kingdom consist of 9 phyla, informally known as the liverworts, mosses, hornworts, lycophytes, ferns, cycads, ginkgos, conifers, and angiosperms

Land plants (embryophytes)

Primarily terrestrial habitat; alternation of two multicellular generations—diploid sporophyte and haploid gametophyte; multicellular embryos are nutritionally dependent on maternal gametophyte for at least some time during development; spore-producing sporangia; gamete-producing gametangia; tough-walled spores

concept

The diversity of modern gymnosperms includes three modern phyla that are all important to human life; cycads, Ginkgo blob, and the conifers (including Gnetales)

Which of the following descriptions most accurately represents how the plant gametophyte has changed through time?

The first plant gametophytes were, like those of modern bryophytes, larger than the earliest plant sporophytes

flower

a short stem bearing reproductive organs that are specialized in ways that enhance seed production

concept

The monophyletic liverwort, moss, and hornwort phyla are together known informally as the bryophytes

alteration of generations

The phenomenon that occurs in plants and some protists in which the life cycle alternates between multicellular diploid organisms, called sporophytes, and multicellular haploid organisms, called gametophytes.

pollination

The process in which pollen grains are transported to an angiosperm flower or a gymnosperm cone primarily b y means of wind or animal pollinators

concept

The seed plants (also called spermatophytes) consist of the gymnosperms, with exposed seeds, and the angiosperms, with seeds enclosed in fruits

sporopollenin

The tough material that composes much of the walls of plant spores and helps to prevent cellular damage during transport in air

concept

The two largest and most diverse lineages of flowering plants are the monocots and eudicots

vascular system

This system allows water and minerals then up by roots to move through stems and leaves and allows sugar produced in leaves to move into locations where the sugar is respired to produce ATP.

petal

a flower organ that usually serves to attract insects or other animals for pollen transport

gymnosperm

a plant that produces seeds that are exposed rather than seeds enclosed in fruits "naked seeds" cycads, ginkgos, and conifers lack flowers, fruits, and endosperm

legumes

dry pods and dry fruits split open down both sides when seeds are mature, thereby releasing them ex) peas, grains, nuts,

Which of the following plant traits represent examples of plant adaptations that are useful to humans? a) lignin-walled xylem b) stems, leaves, and roots c) seed endosperm d) secondary metabolites e) all of the above

e) all of the above

Liverworts

earliest to appear and thus serve as useful models of the earliest land plants

Lycophytes

earliest-divergent group of vascular land plants those having conduction systems that also provide skeletal strength, do not produce seeds. In the ancient past, these were more abundant, larger in size, and more diverse than they are now.

style

elongate middle portion of the pistil

Place the plant structures in correct order, starting with earliest evolved and ending with most recently evolved.

embryo, tracheid, seed, flower

Which sequence of critical adaptations reflects the order of their appearance in time?

embryos, vascular tissue, seeds, flowers

Hornworts

evolutionary important because they are closely related to lycophytes and other land plants that have a well-developed system for internal conduction of water, minerals, and organic compounds.

Which phylum among the plants listed has vascular tissue?

ferns

The primary function of a fruit is to

foster seed dispersal

Bryophytes

liverworts, mosses, and hornworts. The modern nonvascular land plants. relatively small in stature and are most common and diverse in moist habitats, lack traits allowing them to grow tall or reproduce in dry places. Have a dominant (larger and longer-lived) gametophyte generation; the sporophyte is a relatively small and short-lived phase that does not branch. Gametophytes are close to crown, sporophytes are little shoots that spring up

ovary

lowermost portion of the pistil, which encloses and protects ovules

What are the two vascular plants that do not produce seeds?

lycophytes and ferns

alkaloids

nitrogen-containing secondary metabolites have potent effects on animal nervous system caffeine, nicotine, morphine, ephedrine, cocaine, and codeine

The bodies of all land plants are primarily composed of

tissues defined as close association of cells (bodies composed of tissues have a lower surface area-to-volume ratios than simpler green algal bodies, and, thus less readily lose water in dry air by evaporation