plant evolution & diversity overview field botany – lecture 01 dr. donald p. althoff lec 01

Plant Evolution &

Diversity Overview

FIELD BOTANY – Lecture 01

Dr. Donald P. Althoff

LEC 01

SEEDS & FRUITS (not ___________)

ANGIOSPERMS

Algae-to-Plants: Land Conquered

• _______ or rootlike structures

• Conducting _________

• Stiffening substance __________

• Waxy ___________

• Pores called ____________

protista *Algae—plant-like _________ organisms

mosses ferns conifersFlowering

plants

_______________

_____________

______

________

Reproduction on land “key”• Needed to have new method to

transport sperm to eggs

• Accomplished by having sex cells carried by _____…or ____…or ________

• And, _______ of developing embryos from __________...

Evolutionary process…con’t

• First, ________

• Followed by _______…

• Then, in the most advanced plants, ________________

ALTERNATING GENERATIONSGametophyte = (n) produces gametesSporophyte = (2n) production of spores by meiosis

Think 4 Major Divisions

BryophytaPteridophyta Coniferophyta

Anthophyta

Division: BryophytesLIVERWORTS & MOSSES

• ~16,000 species• _____ true roots, leaves & stems• root equivalent -- RHIZOIDS• ____________ plants• rely on diffusion or poorly developed

conducting tissues to distribute water & nutrients

NO

N-v

ascu

lar p

lant

s

LIVERWORTS & MOSSES…con’t

• most are _______ (2cm) max height

• main adaptation to land:_____________

REPRODUCTIVE STRUCTURESarchegonia (egg develops)antheridia (sperm formed)

LIVERWORTS & MOSSES…con’t

• sperm must swim to egg through a ____ ___________

• egg emits a _______________ to aid in location by the sperm

• timing of reproduction MUST coincide with _________________…this is very __________ in dry environments

VASCULAR PLANTS (3 MAJOR CATEGORIES)

• Seedless: Club mosses,horsetails, & ferns

• Seed-bearing: Conifers (pines)flowering

plants

vasc

ular

pla

nts

Vascular, ___________ bearing plantsFERNS & CLUB MOSSES

• PTERIDOPHYTA—fernsmost successful

(~12,000 species)• LYCOPHYTA--club mosses

(ground pine)(~1,000 species)

• SPENOPHYTA--horsetails(~15 species)

FERNS & CLUB MOSSES…con’t

• Distribution and dominance-wise, these plant divisions _____ seen better days…

• Life cycles, again, tied to moist conditions…ex: dominant plant body for ferns

is the sporophyte (frond)

Non-flowering, seed bearing plants Plants PINES, GINKGOS, & CYCADS

• Pines (~500 species) (Conifers)

• Ginkgos (1 species: Ginkgo biloba… can you remember this one?)

-- male & female trees-- extinct in wild-- resistant to air pollution

• Cycads (~160 species)

Conifers = EVERGREENS(Division: Coniferophyta)

• Gymnosperm = “____________” in Latin• Pines, spruces, firs, hemlocks, & cypresses• Once more ______________ and dominant on

land• Most are extremely well-adapted to _____(cold),

____ conditions….

Conifers…con’t

• Dry & cold environment adaptations:a) thin needles with ______ cuticle

b) _____ contains “antifreeze”(what gives it a “piney” fragrance)

• How do these adaptations help????

Conifers…reproductive cycle• Dominant form: _____ = diploid sporophyte

• Male & female cones• Pollen (from male cones) dispersed by wind• Pollen landing on scale of female cone

produces pollen tube that burrows into female gametophyte

Flowering Seed Plants ANGIOSPERMS

• Division: ANTHOPHYTA (“anthro” is Greek for “_______”)

• “Angiosperm” is Greek for “________ ___________________” ….angiosperms produce their seeds enclosed within a fruit

• Diverse group….corn, oaks, water lilies, cacti, and buttercups

Angiosperms…con’t• ~230,000 species• “the” ________ plant division for over 100

million years

• 3 major adaptations:a) flowers

b) fruits

c) broad leaves

1

2

3

Flowers• Produced by sporophyte • Males & females generally in same

flower• _______ formed in anther (male)• _______ formed in ovary (female)• Fertilization accomplished with pollen

tube through the stigma

1

All in!

Fruit

• Contains the ovary which contains a ______________

• This adaptation greatly enhanced __________.most seeds pass through digestive tracts of animals unharmed. Some attached to fur.

2

Seeds

• Important source of food for humans….including prehistoric times

a) easy storage (if kept dry)b) source of protein, oils,

carbohydrates, & vitamins…same goes for germinating seed

Broad Leaves

• During favorable conditions…particularly in tropical and temperate zones…_____ ______________ available to collect sunlight for photosynthesis.

• Excess production allows for storage…and subsequent dormant period

3

Broad Leaves…liabilities

• Broad, ________ leaves are more appealing to herbivores than conifer leaves (needles)

• To __________….some have developed defenses: a) thorns, spines, & resins b) chemical compounds that may be toxic or distasteful

protista *Algae—plant-like single-cell organisms

mosses ferns conifersFlowering

plants

All multicelluar

Vascular tissue

Seeds

Flowers