Midterm 2 Flashcards
(343 cards)
What kinda tree is the tallest?
redwood
What is the oldest type of tree?
bristlecone pine
What is the biggest tree?
sequoia
What is the green revolution?
When major progress made around the 1950-60’s with fertilizers, irrigation, etc. – worried it maxed out agricultural products
What are the 2 definitions of a seed?
- a mature, fertilized ovule that acts as a dispersal unit for seed plants
- contains an embryo, food source and seed coat (testa)
What is 2n composed of?
diploid, 2 chromosomes each composed of 2 alleles (4 alleles total – allele = version of a gene)
What is n composed of?
haploid, 1 chromosome
What is the sporangia
aka “mother cell”, is a sexual organ where meiosis occurs to produce spores (n)
What is the alternation of generations life cycle?
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)
What is a gametophyte?
the haploid gamete producing phase in the life cycle
Formed in sexual organs (antheridia / archegonia) – reproduces sexually – undergoes mitosis
Whats the difference between a gamete and a spore?
spore: germinates and develops into a sporeling
gamete: combines with another gamete to form a zygote
What is a sporophyte?
the diploid spore producing phase in the life cycle – reproduces asexually – undergoes meiosis
Bryophytes (gam/spo dominant, homo or hetero)
small, non vascular plants (mosses, liverworts and hornworts) – gametophyte dominant – homosporous
Ferns (gam/spo dominant, homo or hetero)
sporophyte dominant – homosporous
Gymnosperms aka seed plants (gam/spo dominant, homo or hetero)
sporophyte dominant – heterosporous
What is homospory?
the production of one type of spores asexually (same size and type)
What is heterospory?
the production of 2 different types of spores asexually (2 sizes and 2 sexes)
Conifer characteristics
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)
What are pollen 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
What are seed cones?
each woody scale on the cone has 2 wings and 2 seeds (ovule = seed before fertilization)
Ovule characteristics
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
What are serotinous cones?
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
Yews and juniper berry special characteristics
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
What are the big 3?
wheat, corn and rice