~ Algae ~ Bryophytes ~ Ferns ~ Angiosperms ~ Gymnosperms Diversity of organisms ~ Algae ~ Bryophytes ~ Ferns ~ Angiosperms ~ Gymnosperms

Evolution

Algae This is a collective name for a varied group of phyla with no one diagnostic feature. They are normally aquatic or live in damp terrestrial habitats. Subdivisions are mainly associated with biochemical differences related to photosynthesis.

Algae are without roots, stems or leaves. All contain chlorophyll and so can make their own food by photosynthesis. The cells are long and their cellulose cell walls are covered by a layer of mucilage. The major are green, but some are brown or red.

Feature of plant Vascular tissue no support Air sac, by water sporophyte gametophyte Stem root leave Water absorption diffusion Reproduction Binary fission dispersal swim

Structure of algae

diatom

Type of algae Green algae Brown algae

Volvox

Example of algae egregia analipus

Bryophytes Bryophytes are small green plants with simple leaves, stems but no roots. They grow close to ground, and usually do not grow more than 2cm in length. They do not have vascular tissue which enables the plant to grow tall, and which they have no support to be stiff. They are anchored in the ground by delicate structure called Rhizoid. They live in damp places.

- The life cycle of Bryophytes begins with the release of haploid spores. Spores that geminate begin cell division, this produces the filament that will eventually form a gametophyte.

Photo of bryophytes

moss

liverwort

Life cycle of bryophytes

Archegonia

Feature of plant Vascular tissue No true support turgid sporophyte Only capsule parasite gametophyte gametophyte Photosynthetic, mainly Stem root leave No real root but rhizoid Water absorption diffusion Reproduction Sexually archegonia, antheridia dispersal Capsule dry up, mechanical

Ferns Their roots grow horizontally underground Ferns consist of true stems, roots, leaves and vascular tissues. Their roots grow horizontally underground The preferred habitat of a fern is in the wetlands, or in moist woody areas; they also prefer damp shaded area. They need water for fertilization. As for reproduction, they reproduce by spores and vegetatively by rhizomes, which are horizontal underground stems.

Photo of ferns

Life cycle of ferns

Feature of plant Vascular tissue simple support tracheid sporophyte Major, large, water resistant gametophyte Minor, small Stem root leave Have but root is simple as rhizoid Water absorption rhizoid Reproduction Gametophyte archegonia antheridia dispersal Sorus dry up mechanical

Gymnosperms(conifers) Gymnosperms are large evergreen trees with seeds growing inside cones for reproduction. Most of them have needle-shaped leaves. It does not have flowers but seeds. The seeds are naked. They are not enclosed in food and borne on structure called cones. Example is pine.

In conifers, the region of primary cell wall in the centre of the pit is thickened with a deposit of waxy material, forming a structure known as a torus. The phloem of conifers contains sieve cells, fibres, and parenchyma cells, but companion cells are absent.

Examples of gymnosperms Pine

Feature of plant Vascular tissue have support woody sporophyte all gametophyte Minimize to cone Stem root leave Water absorption root Reproduction cone dispersal wind

Angiosperms All angiosperms have flowers for reproduction. Their seeds are produced inside the ovary. Angiosperms form the dominant terrestrial vegetation today. They are found in a wide range of habitats and have even re-established themselves in freshwater and the sea.

- They are extremely well suited to life on land both in their morphology. - They are divided into dicotyledons and monocotyledons.

Morphology of herbaceous dicotyledon

Morphology of herbaceous monocotyledon Lily

Comparison of moncotyledoneae and dicotyledoneae

Life cycle of angiosperms

Feature of plant Vascular tissue have support Turgid or woody sporophyte all gametophyte Minimize to flower Stem root leave Water absorption root Reproduction Pollen by wind or insect dispersal Water wind animals mechanic

Summary of plant kingdom

TSANG MAN YEE 6B (26) YIK WAI TUNG 6B (31) PRESENTED BY: TSANG MAN YEE 6B (26) YIK WAI TUNG 6B (31)