Lesson 1: terrestrial Plant Adaptations

What are the 2 types of green algae?

Chlorophytes: never made it to land

Charophytes: Sister group to all land plants

What are land plants

They have a single ancestor

Have multicellular haploid and diploid cells

What are the 2 major challenges to terrestrial life

Desiccation and Transportation (of water and minerals/nutrition)

What is desiccation? What are two physiological adaptations that overcame it?

Cuticles: a waxy covering on the surface to protect from dissication. Prevent water loss but inhibit gas exchange. (Most land plants have it)

Stomata: Small openings which aid in gas exchange

• Allow CO2 in and H2O out

• Give off excess oxygen

Describe the transportation system for land plants

Tracheids: special cells that some plants have that aid in water and mineral transport

• xylem: transport water and minerals

• Phloem: food transfer system (sucrose and hormones,). They are involved in the process of healing so dispered throughout the whole plant

What are 4 other challenges of land life

Structural support:

• have to be able to support your own bosy without water

• Mechanism is called lignin (polymer) its found in the cell walls and strnegthens them

New reproductive strategies

• you can’t use water to reproduce

• solution: wind, animals

Predation

• animals eat you on land

• thorns, foul taste, poisenous

Poor conditions

• symiotic association

  • Fungi-micorrhizae: extract minerals from soil

What is a haploid vs. Diploid

Haploid has one set of chromosomes, diploid has 2

Describe the haploiddiplontic life cycle

• Gametophyte (n) goes through mitosis o form egg and sperm.

• Fertilization (start of 2n) develops into zygote and then embryo and then sporophyte

• Sporophyte turns into spore mother cell which prodcuces spores thorugh meiosis (back to n)

• spore turns into gametophyte

What is mitosis

Mitosis is a type of cell division that produces two genetically identical daughter cells from one parent cell (leads to egg and sprem)

Meiosis

creates four daugther cells that are genetically unniue, half the number of chromosomes

How does the difference in life cycles link to different sophistication of plants

Dominance of diploid generation during evolution causes greater genetic variety. More sophisticated plants are diploid dominant

Mosses are primative so gametophytes are dominant part of life cycle

What are the 3 Bryophytes

Liverworts, mosses, hornwarts

Describe Byrophytes and their features (Gametophyte or sporophyte dominant, vascular or non, vascular system, sexual reproduction)

Gametophyte dominant

• photosyntehtic

• primitive

Non-vascular

Non-tracheids

• they have conducting cells (primitive type of tracheids)

• Because they have a weak transport system they are small in size

• require water for sexual reproduction so they are common in moist areas

Dont have true roots for water absoprtion

• they have rhizoids

What are the three types of Tracheophytes, and do each need water to reproduce

Lycophytes (club mosses) need water to reproduce

Pterophytes (ferns, whip ferns, horsetails) need water to reproduce

Seed plants (gymnosperms and angiosperms) dont need water to produce

Describe tracheophytes and their features (Gametophyte or sporophyte dominant, vascular or non, vascular system, sexual reproduction)

Sporophyte dominant (2n)

Colonized land by having good vascular tissue

• xylem: vascular tissue for water absoprtion and dissolved minerals. TOo much water opens up the stomates. they go roots to leaves

• Phloem: vascular tissue adopted for sucorse, hormones, and other organic compounds.

waxy cuticle

some need water for reproduction

Lycophyte features

Sporophyte dominant

Vascular tissue

• roots and stems

No vascular tissue in leaves ‘

No seeds

• so need water required for fertilization

Sister group to all other vascular plants

Pterophytes: Ferns and relatives

Sporophyte dominant

Vascular tissue

• roots, stems, true leaves (euphylls)

No seeds

• water for fertilization

Eupylls have large surface area

Seed plants (what are the evolutionary advatages of seeds)

Protect embryo, food supply, dispersal, dormancy

Dominante terrestrial landscapes

Gymnosperms (what does it mean, what are the 4 common groups)

Naked seed

seed seperate gymnosperm from ferns and allies

• seed is exposed that is not completely enclosed by sprophyte tissue

• when seed is mature, it may be enclosed by sporophyte tissue

Cyads: sub tropical and tropical regions

• slow growing

• like palm trees but they produce cones

Welwitschia: desserts of southwestern africa

Ginko: native to china

• only living species of a more widespread group

• maple plants are preffered for cultivation

Conifers

Angiosperms (meaning, advantage of flowers, pollination)

Seed in a vessel

fruits

flowers

• attract pollinators thrpugh morphology, color, iris, nectar

Most evolutionary advanced land plants

most diverse and widespread land plants

Vessel is a diploid sporophyte tissue is called carpel

Carpel

• originated from modified leaves it encloses the seed and the fruit develops

Pollen with 2 sperm

Double pollination