BSC 2011: Biological Diversity - Plants and the Conquest of Land

These flashcards cover key concepts from the BSC 2011 lecture on biological diversity focusing on plants and their adaptations to land environments.

What are the derived characteristics present in land plants that distinguish them from their nearest algal relatives?

Land plants exhibit alternation of generations, multicellular dependent embryos, walled spores in sporangia, multicellular gametangia, and apical meristems.

What adaptations allow land plants to thrive in a terrestrial environment?

Adaptations include new tissue from meristems, a cuticle, stomata, tough-walled spores, and structures for reproduction on land.

What is the significance of lignin in vascular plants?

Lignin provides structural support, allowing plants to grow taller and to adapt to life on land.

What transformed Earth's ecology during the appearance and spread of seedless plants?

The appearance of seedless plants led to the formation of the first forests, which helped sequester carbon dioxide, enriched soils, and contributed to global cooling.

Define the term 'microphyll'.

A leaf with a single branch of vascular tissue.

Define the term 'megaphyll'.

A leaf with a branched vascular system.

In what generation does meiosis occur in the alternation of generations in land plants?

Meiosis occurs in the sporophyte generation.

What structure do gametophytes use to produce haploid gametes?

Gametophytes produce haploid gametes by mitosis.

What are the primary groups of land plants based on vascular tissue and seeds?

The main groups are Bryophytes, Seedless vascular plants, Gymnosperms, and Angiosperms.

What is the dominant generation in bryophytes?

In bryophytes, the dominant generation is the gametophyte.

How do seedless vascular plants reproduce?

Seedless vascular plants rely on moist conditions for reproduction as they have flagellated sperm that swims to eggs.

What role did seedless plants play in reducing atmospheric CO2 levels?

Seedless plants produced decay-resistant tissues that contributed to carbon burial, thus reducing CO2 in the atmosphere.

What is a distinctive feature of land plant bodies?

Land plant bodies arise from apical meristems, leading to complex bodies with specialized tissues and organs.

What distinguishes the sporophyte generation from the gametophyte generation in land plants?

The sporophyte generation is diploid (2n) and produces spores, while the gametophyte generation is haploid (n) and produces gametes.

What adaptations do land plants have to minimize water loss?

Land plants have a waxy cuticle and stomata that help reduce water loss while allowing gas exchange.

What indicates that vascularization allowed earlier land plants to grow larger?

Vascularization provided better access to sunlight and the ability to disperse spores effectively.

What is the ecological impact of the first forests formed by seedless vascular plants?

The first forests reduced atmospheric CO2 levels and contributed to global cooling.

What characteristic of the fern life cycle is true?

Fern sporophytes eventually grow independently of the female gametophyte.