PLANTS eukaryotic autotrophic (through photosynthesis) cells have walls made of cellulose

ALTERNATION of GENERATIONS Animals are diploid individuals with only haploid stages in sperm and egg. Plants alternate between a haploid and a diploid generation. Diploid (2n) = sporophyte; haploid (n) = gametophyte.

HIGHLIGHTS OF PLANT EVOLUTION

Four key adaptations to life on land 1.Dependent embryos, which are nourished and protected on the parent plant. 2.Vascular tissues (xylem and phloem) transport water, nutrients and provides support for upright stems found in most modern plants.. 3.Seed producers appeared and these plants dominate the plant kingdom today. 4.Flowers provide a new process for plant reproduction.

Evolution of Plants TransportPhylumExamples Non-vascular (live in water) Algae Seaweed (unicellular, colonial, & multicellular) Bryophytes Moss, liverworts Vascular (true land plants) Pteridophytes Ferns, horsetails Gymnosperms Evergreen trees Angiosperms Flowering plants

Unicellular Algae Euglena & Diatoms – protists or plants? Chlamydomonas (right) - unicellular. - moves using flagella. Volvox – lives in colonies. Some cells are specialized!

Unicellular to Multicellular Plants Unicellular-all of life’s activities occurs within a single cell. Colonial – Some cell specialization distributes jobs. Multicellular-various specialized cells, which perform different functions and are interdependent.

Spirogyra – multi-cellular - cells are stacked end to end. - specialization of some cells.

Ulva (sea lettuce) – multi-cellular - releases gametes for reproduction.

Green AlgaeBrown AlgaeRed Algae Chlorophyll A & B Chlorophyll A & C Chlorophyll A & D

Algal Structure Blade - thin for diffusion of nutrients & gas - photosynthetic - may secrete mucous Float (air bladder) – brings algae closer to surface and sunlight Stipe - photosynthetic extension Holdfast - anchors algae

Kelp Forests Provide habitat for numerous organisms and minimize the pounding effects of waves.

- Drying out - transport of nutrients. - Reproduction (sperm moving to egg) Challenges of moving to land!

Bryophytes (moss, liverworts, & hornworts)

Bryophytes Can survive on land but are heavily dependant on water.This is why they like shady areas. Depend on diffusion for transport Are thin and dry out easily Sperm need to swim to the egg Have rhizoids instead of true roots

Moss have a dominant haploid gametophyte generation Life cycle of a moss

Pteridophytes (ferns)

Pteridophytes Have true roots and vascular tissue for transport up stem. Have a waxy cuticle on fronds (leaves) to prevent drying out. Sperm do still need water to swim to the egg on the prothallus

Ferns have a dominant diploid sporophyte generation Life cycle of a fern

Gymnosperms (evergreens) Have cones for reproductive structures. Rely on wind for pollen dispersal from the smaller male cone to the larger female cone. Produce exposed (“naked”) seeds on their cones. Have tough needles which withstand cold climates.

Gymnosperm Lifecycle Single fertilization

Angiosperms (flowering plants) Have flowers for reproductive structures. Use wind and animals for pollen dispersal Produce protected seeds that contain food for their embryo. Have broad flat leaves.

Plant Porn???

Plant Peep Show

Angiosperm Lifecycle Double fertilization

Flower Diversity