LO5

Plants belong to which eukaryotic clade?

Archaeplastids

What did land plants evolve from 450 bya?

A multicellular, aquatic green algae ancestor

Two similarities between plants and green algae supporting the idea that plants descended from multicellular green algae.

Similar DNA and both use the same photosynthetic pigments (chlorophyll a&b, carotenoids).

What prevents plants from drying out on land?

A waxy cuticle covering the above-ground parts

Stomata

Allows for gas exchange on land

Where is stomata found?

Microscopic pores on the leaves and stems that allow the exchange of CO2 and O2

Spores

Reproductive cells adapted on land due to tough outer coat

In what structures are spores produced?

Capsule-like sporangia

Plants have multicellular reproductive organs that produce?

Gametes

Female reproductive organs

Archegonia

What do archegonia produce?

One single egg

What dies the egg develop into?

An embryo protected within the archegonia

Male reproductive organs

Antheridia

What do antheridia produce?

Many sperm

Algae have ___ reproductive organs

Unicellular

Land plants have ___ reproductive organs

Multicellular

Land plants cycle between what phases during their life?

Haploid and diploid generations

The haploid, multicellular generation

gametophyte

The gametophyte plant produces ___ by ___

Haploid gametes by mitosis

How do gametes form a diploid zygote?

Through fertilization

The gametophyte generation is ___ and ___

Haploid and multicellular

The sporophyte produces ____ by ____

Diploid zygote by mitosis

The sporophyte generation is ___ and ___

Diploid and multicellular

First stage of sporophyte generation

Diploid zygote

The zygote develops by ___ into an ___ inside the ___

Mitosis; embryo; archegonium

The embryo develops into a mature ____ plant that produces ___ by ___ inside ____.

Sporophyte; spores; meiosis; sporangia

First stage of gametophyte generation

Spore

Which two characteristics are used to classify plants into four main groups?

Presence or absence of vascular tissue and seeds

Vascular tissue function

Transport water and nutrients and provides structural support

Seed

Embryo with nutrients inside of a protective coat

Three parts of a seed

embryo, stored food, seed coat

What are the bryophytes (nonvascular plants) missing?

Vascular tissue and seeds

What do bryophytes use for dispersal?

Spores

Seed plants

gymnosperms and angiosperms

Do seed plants still produce spores?

Yes, but they use seeds for dispersal.

What do vascular seedless plants lack?

Seeds

The first plants to evolve and colonize land?

Nonvascular plants (bryophytes)

Why don't bryophytes have true leaves, stems, or roots?

They lack vascular tissue that provide structure

Which generation is dominant among bryophytes?

Gametophyte generation

What does the gametophyte plant protect and nourish?

The sporophyte

What other trait did bryophytes retain?

A flagellated sperm that requires external water to swim to the egg

Most common bryophytes?

Mosses

How do mosses prevent soil erosion and aid in soil formation?

Their root-like structures hold soil in place and they secrete acids that break up rocks

Mast plants are?

Vascular

Bryophytes form a ___ group while vascular plants are a ___ group.

Paraphyletic; monophyletic

Vascular tissue allows for larger or smaller size?

Larger

Efficient leaves, stems, and roots require?

Vascular tissue

What generation is dominant among vascular plants?

Sporophyte generation

What advantage do sporophyte plants have?

Being diploid and having vascular tissue

Do gametophytes have vascular tissue?

No

Why would a bentonite plant be dependent on the sporophyte?

Foot nutrition and protection

Prior to the evolution of seed land plants, what dominated?

Vascular seedless plants

What generation is dominant in seedless vascular plants?

sporophyte generation

How is the gametophyte generation independent from sporophyte generation?

It performs its own photosynthesis

Example of seedless vascular plant

A fern is a sporophyte, and its gametophyte is a tiny, vascular, short-lived plant

Why are seedless vascular plants restricted to moist environments?

They have bikont flagellated sperm that requires water to disperse to the egg

The first seed plants

gymnosperms

What did gymnosperms evolve from?

Ancient seedless vascular plants

What generation is dominant in seed plants?

sporophyte generation

Where is the gametophyte commonly found on gymnosperms? Angiosperms?

Cones in gymnosperms; flowers in angiosperms

How are seeds superior to a spore as an agent of dispersal?

Tough outer coat, food supply, and multicellular

Heterosporous

produce two kinds of spores

Female spores

megaspores

Where are megaspores produced?

megasporangia

What do megaspores develop into?

female gametophytes

male spores

microspores

Where are microspores produced?

microsporangia

What do microspores develop into?

male gametophytes

Do microspores or megaspores ever leave the sporophyte parent in which they were produced?

No, they are not released from the sporophyte parent

What was a necessary precursor for the evolution of seeds?

Heterospory

Ovule

Megaspore inside of its megasporangium

What does the female gametophyte produce?

egg (still protected in megasporangium)

What will the egg develop into once fertilized?

Sporophyte embryo

The seed is formed from?

New sporophyte embryo + remaining female gametophyte tissue + outer layer of megasporangium (seed coat)

Where does the entire female gametophyte plant develop?

Within the parent sporophyte plant

Where does fertilization occur?

Sporophyte

In seed plants, what are male gametophytes reduced to?

Microscopic pollen grains

Inside of the ___, microspores develop into ___.

Microsporangia; pollen grain

How are pollen grains dispersed to ovules during pollination?

By wind or animals

Each pollen grain produces a ___ that is transported to an egg for fertilization by a ___.

Flagellated sperm; pollen tube

What is the advantage of the pollen tube?

It eliminates the need for flagella and external water

What have 'naked seeds'?

Gymnosperms

What became dominant plants on land because of the dry climate during the Mesozoic era?

Gymnosperms

Why did gymnosperms outcompete the seedless vascular plants?

They did not have to rely on external water to disperse sperm, and they dispersed seeds.

Most abundant gymnosperms that are dominant in many forests

Conifers

Example of conifers

Junipers and pine trees

How do conifers prevent soil erosion?

Their roots

How are conifers ecologically important

Habitat for many organisms, food, and prevent soil erosion

Flowering plants

angiosperms

What did angiosperms evolve from?

gymnosperms

Majority of plants are?

angiosperms

Purpose of flowers?

reproduction

Within a flower, angiosperm ___ are protected inside of ___.

Ovules; ovary

Upon fertilization, ovule becomes a

Seed

Upon fertilization, ovary becomes a

Fruit

Two functions of fruit

Protects seed and aids in seed dispersal

Function of outer parts of flowers?

Protect the flower and attract pollinators

The ovary contains?

one or more ovules

The ___ contain microsporangia that produce ___

Anthers; pollen grains

Pollen grains in angiosperm contain?

Two sperm