Plant Diversity II

what are derived traits of seed plants

• seeds: self contained structure of embryo, E source, protection

• gametophyte: microscopic, develop from spore, dependent on sporophyte

• heterospory: production of two different spores

• pollen: male reproduction

what are the two spores of heterospory

• megaspore: female gametophyte

• microspore: male gametophyte

how does pollination work

• transfer of pollen to female reproductive structures by wind or animals

• not fertilization

• not water dependent

what are the advantages of seedless plants, a seed and a spore

• seedless plants: spore only protective stage

• seed: multicellular embryo protected by seed coat, viable for days to years, has E source

• spore: single celled, shorter lifespan, no E source

what are gymnosperms like

• cones and conifers

• naked seeds: exposed seeds

what are angiosperm derived traits

• flowers

• fruits

• double fertilization

• endosperm

what are flowers for and what are their layers

• used for sexual reproduction

• sepals: protection during growth

• petals: attract pollinators

• stamens: males reproductive structures

• carpels: female reproductive structures

what is flower diversity

• complete flowers: all foru parts

• incomplete flower: missing one or more parts

what are fruits

• ovary wall matures into fruit as seed develops

• protects seeds and facilitates dispersal

what is double fertilization

• two sperm involved in fertilization

• one sperm fertilizes egg to make a diploid zygote

• one fertilizes “central cell” with two nuclei which leads to triploid 3n cell

what is an endosperm

• triploid 3n cell grows into endosperm

• nourishes developing embryo