Plant Diversity I: How Plants Colonized Land

Flashcards about plant diversity and adaptations for land colonization.

Plant Colonization of Land

Plants colonized land approximately 500 million years ago, with the first forests appearing 385 million years ago.

Key Innovations for Plants

Key areas of innovation for plants include morphology, motility, metabolism/energy, and reproduction.

Charophytes

Green algae called charophytes are the closest living relatives of plants.

Plant Origin

Plants originated from green algae about 470 million years ago.

Viridiplantae

Viridiplantae refers to green plants; land plants were the first organisms to thrive with tissues completely exposed to the air.

Green Algae

Photosynthetic protists in freshwater habitats and the closest living relatives to land plants.

Land Plant Challenges

Challenges of terrestrial life for plants include maintaining moisture, obtaining resources from soil and air, supporting the body in air, and reproducing/dispersing offspring without water.

Alternation of generations

Life cycle involving distinct haploid sexual and diploid asexual stages.

Walled spores

Haploid germ cells produced in sporangia which are the receptacle in which asexual spores are formed.

Apical Meristems

Localized regions of cell division in the tips and roots.

Cuticle

Waxy coating which prevents dehydration.

Stomata

Pores for gas exchange.

Embryophytes

Plants are called embryophytes because of the dependency of the embryo on the parent.

Sporopollenin

Polymer that makes spore walls resistant to harsh environments.

Apical Meristems

Localized regions of cell division at the tips of roots and shoots that enable elongation for resource acquisition.

Cuticle Function

Prevents dehydration but also prevents CO2 absorption.

Stomata Function

Pore surrounded by guard cells which open and close to allow gas exchange.

Nonvascular Plants

Plants that do not have vascular tissue and produce spores not seeds (e.g., mosses).

Seedless Vascular Plants

Plants that have vascular tissue and produce spores not seeds (e.g., ferns).

Seed Plants

Plants that have vascular tissue and produce seeds.

Gymnosperms

Seed plants that produce seeds but no flowers or fruits (e.g., ginkgos).

Angiosperms

Seed plants that have vascular tissue and produce flowers, seeds, and fruits (e.g., viburnums).

Bryophytes

Nonvascular plants including liverworts, hornworts, and mosses.

Rhizoids

Root-like structures that anchor gametophytes to the substrate.

Gametangia

Protected gametes from drying and physical damage.

Sphagnum

Also known as peat moss, forms extensive deposits of partially decayed organic material known as peat.

Ferns Characteristics

Seedless vascular plants with sporophyte dominant lifestyle.

Tracheids

Long, tapering, water-conducting cells with lignin.

Vessel elements

Shorter and wider water conducting cells with end gaps.