BIS 2C MT 2 Part 1

What is a plant?

An autotrophic eukaryotic organism that converts light energy into chemical energy through photosynthesis using chlorophyll inside chloroplasts

How did the chloroplast in plants originate?

It arose via a unique episode of primary endosymbiosis of a cyanobacterium

What are the diagnostic features of all plants?

The possession of a chloroplast from primary endosymbiosis and the photopigment chlorophyll a

When did plants arise?

They are monophyletic and arose approximately 1.2 billion years ago

What were the major challenges plants faced when transitioning to land?

Desiccation, water transport, structural support against gravity, intense UV radiation, and dispersal of gametes and progeny

What benefits did the terrestrial environment offer early plants?

Increased access to sunlight, better access to oxygen and carbon dioxide, and initially decreased competition and herbivory

Which "algal" innovations appeared before the move to land?

Storing starch in chloroplasts, chlorophyll b, and the retention and encasement of the egg on the parent plant

Which group is the sister group to Land Plants?

Charales

What characterizes a "Sporic" life cycle?

It is characterized by an alternation of multicellular haploid and diploid generations

What are the vegetative innovations of Land Plants?

The cuticle, pigments for UV protection, and mycorrhizae

What is the function of sporopollenin?

It is a protective coating that surrounds air

Define antheridia and archegonia

Antheridia are multicellular sex organs that produce sperm, while archegonia are multicellular sex organs that produce eggs

Why are "Bryophytes" restricted to cool, damp habitats?

They lack a true vascular system, true leaves, stems, and roots, and have swimming sperm that require water for reproduction

Which "Bryophyte" groups possess stomata?

Mosses and Hornworts

What were the two major innovations of the extinct Rhyniophytes?

A branched sporophyte with apical sporangia and a vascular system

What are the diagnostic features of Vascular Plants?

A sporophyte that is nutritionally independent at maturity and tracheid cells with lignified cell walls

How does xylem differ from phloem?

Xylem conducts water and minerals via dead tracheid cells, while phloem conducts products of photosynthesis via living sieve

What is the evolutionary origin of microphylls?

They evolved from sterile lateral sporangia in Lycophytes

What is the evolutionary origin of megaphylls?

They evolved from modified side branches in Euphyllophytes

What is the difference between homospory and heterospory?

Homosporous plants produce one type of spore for hermaphroditic gametophytes, while heterosporous plants produce two types of spores for separate male and female gametophytes

What are the three main lineages of Lycophytes?

Club mosses, spike mosses, and quillworts

What lineages make up the Euphyllophytes?

Monilophytes and Seed Plants

What is overtopping growth and its adaptive value?

It is the asymmetric division of the apical meristem that allows for taller growth, better sunlight competition, and enhanced spore dispersal

In which groups did heterospory evolve independently?

Within Lycophytes (spike mosses), Monilophytes (some leptosporangiate ferns), and the MRCA of Seed Plants

What lineages are included in the Monilophytes?

Whisk ferns, horse