Midterm 2

redwood

bristlecone pine

sequoia

When major progress made around the 1950-60’s with fertilizers, irrigation, etc. – worried it maxed out agricultural products

• a mature, fertilized ovule that acts as a dispersal unit for seed plants • contains an embryo, food source and seed coat (testa)

diploid, 2 chromosomes each composed of 2 alleles (4 alleles total – allele = version of a gene)

haploid, 1 chromosome

aka “mother cell”, is a sexual organ where meiosis occurs to produce spores (n)

alternation between a haploid (n) gametophyte phase and a diploid (2n) sporophyte phase in the life cycle of a sexually reproducing plant (circle of gametophyte to sporophyte)

the haploid gamete producing phase in the life cycle Formed in sexual organs (antheridia / archegonia) – reproduces sexually – undergoes mitosis

spore: germinates and develops into a sporeling gamete: combines with another gamete to form a zygote

the diploid spore producing phase in the life cycle – reproduces asexually – undergoes meiosis

small, non vascular plants (mosses, liverworts and hornworts) – gametophyte dominant – homosporous

sporophyte dominant – homosporous

sporophyte dominant – heterosporous

the production of one type of spores asexually (same size and type)

the production of 2 different types of spores asexually (2 sizes and 2 sexes)

Seeds are in cones (naked seeds) Cones = a collection of reproductive structures on a short axis 2 types of cones on the same tree (pollen male cones and seed female cones)

many microsporangia that produce microspores which become microgametophytes (pollen) – have 2 air sacs (air bladders) on either side that help with wind distribution (reduce density) – pollen consists of 4 nuclei and is dispersed only through wind

each woody scale on the cone has 2 wings and 2 seeds (ovule = seed before fertilization)

Surrounded by integument (2n - tough) Has 2-5 archegonium, each with their own egg (n) (only 1 seed in total carries on tho) Female gametophyte (n) acts as the food source

require heat to open and release seeds (resin glues it together) Clears the landscape so lots of sunlight Provides lotsa nutrients (ash) in the soil to grow

have individual seeds surrounded by a red fleshy aril (part of the seed coat) // juniper berries are fleshy seed cones, not really berries or fruits

wheat, corn and rice