Embryophyte

Embryophytes

• Embryophytes are a clade of plants, also known as Embryophyta or land plants.
• They emerged from freshwater charophyte green algae.
• Embryophytes consist of bryophytes and polysporangiophytes.
• They include hornworts, liverworts, mosses, lycophytes, ferns, gymnosperms, and angiosperms.
• Embryophytes have diplobiontic life cycles.
• They are primarily adapted for life on land.
• They have specialized reproductive organs.
• They obtain biological energy through photosynthesis.
• They release oxygen as a byproduct of photosynthesis.
• They have alternation of generations in their life cycle.
• They have multicellular gametophytes that produce sperm and eggs.
• Fertilization takes place within the archegonium.
• The zygote develops into a protected embryo.
• In most embryophytes, the sporophyte generation is dominant.
• Embryophytes evolved from streptophyte algae.
• Streptophytes invaded land during the Ordovician period.
• Freshwater adaptation pre-adapted embryophytes to tolerate land conditions.
• Molecular evidence supports the relationships among embryophyte groups.
• Present-day embryophytes form a clade.
• Mosses, hornworts, and liverworts are non-vascular land plants.
• They have a haploid-dominant life cycle.
• Sporophytes are unbranched structures in these plants.
• They rely on water for dispersal of gametes.
• Non-vascular land plants dominate in humid or seasonally moist environments.

Rise of Vascular Plants

• Plants evolved vascular tissue during the Silurian and Devonian periods.
• Vascular tissue contains cells with lignin-strengthened walls called tracheids.
• Some early plants had water-conducting tissue similar to mosses but a more developed sporophyte.
• Other plants, like Rhynia, had a similar life cycle but simpler tracheids.
• The gametophyte and sporophyte stages in vascular plants are equally independent.
• Lycophytes, such as clubmosses and spikemosses, make up less than 1% of living vascular plants.
• Lycophytes have small leaves called microphylls or lycophylls.
• Microphylls evolved from outgrowths on stems and later acquired veins.
• Tree-like lycophytes dominated the landscape during the Carboniferous period.
• Euphyllophytes, comprising over 99% of vascular plant species, have large true leaves called megaphylls.
• Ferns and horsetails form a clade and disperse through spores.
• Whisk ferns and horsetails have reduced leaves compared to true ferns.
• Ferns are a diverse group with approximately 12,000 species.
• Stereotypical ferns have broad, divided leaves that unroll.
• Early fossil horsetails had broad leaves with branching veins.

Seed Plants

• Seed plants appeared towards the end of the Paleozoic era.
• They reproduce using desiccation-resistant capsules called seeds.
• Seed plants have two types of spore-forming organs: megasporangia and microsporangia.
• Megasporangia produce a single large spore that develops into a tiny gametophyte.
• Microsporangia produce microspores that develop into pollen grains.
• Seed plants include gymnosperms and angiosperms.
• Gymnosperms have exposed ovules or seeds, while angiosperms have enclosed ovules within carpels.
• Angiosperms typically have additional structures like petals, forming flowers.
• Gymnosperms and angiosperms are the two clades of seed plants with living members.
• Seed plants underwent complex changes to evolve from spore-dispersing ancestors.

Evolution of Land Plants

• Land plants evolved from a single type of algae.
• The earliest land plants were likely small and lacked roots and leaves.
• The evolution of land plants involved the development of specialized structures such as roots, leaves, and vascular tissues.
• Land plants played a crucial role in shaping terrestrial ecosystems and providing habitats for other organisms.
• The evolution of land plants was a key event in the colonization of land by organisms.
• Land plants have a complex life cycle that alternates between a haploid gametophyte phase and a diploid sporophyte phase.
• The gametophyte phase produces haploid gametes through mitosis.
• Fertilization occurs when a sperm from the male gametophyte fuses with an egg in the female gametophyte.
• The fertilized egg develops into a diploid sporophyte, which produces spores through meiosis.
• The spores are dispersed and germinate into new gametophytes, completing the life cycle.
• Land plants exhibit a wide range of morphological features, including different types of leaves, stems, and roots.
• The major groups of land plants include bryophytes (mosses, liverworts, and hornworts) and vascular plants (ferns, gymnosperms, and angiosperms).
• Bryophytes lack true roots, stems, and leaves, while vascular plants have specialized vascular tissues for transport.
• The evolution of leaves allowed land plants to increase their photosynthetic surface area and improve their ability to capture sunlight.
• The diversity of land plants is vast, with over 300,000 known species, making them one of the most successful and widespread groups of organisms on Earth.

Adaptations to Terrestrial Life

• Land plants have evolved various adaptations to survive and thrive in terrestrial environments.
• The development of a cuticle, a waxy layer on the surface of leaves and stems, helps reduce water loss.
• The

Embryophyte Data Sources