Flashcards in CH 30: Gymnosperms and Angiosperms Deck (24)
What are the features of gymnosperms/angiosperms?
-embryos/zygotes retained in maternal tissue
-tissues used to transfer nutrients from mother plant to embryo (similar to placenta)
What are plant embryos?
Young sporophytes that develop from zygotes
What are the important reproductive features of land plants?
-Embryos that they protect
-placental transfer tissues that transfer nutrients
What is the evolutionary importance of leaves?
Provide high surface area to capture sunlight and more structural support
How did Lycophylls evolve into Euphylls?
-Lycophylls (early small leaves) had many green branches
-Eventually one branch dominates and grows taller
-Photosynthetic tissue fills in spaces
What is a seed and how does it work?
-megasporangia with a egg-producing gametophyte inside enclosed by protective layer
Seed plants produce two distinct types of spores in two different types of sporangia
-microspores in microsporangia
-megaspores in megasporangia
Fertilization occurs after Pollination
Male gametophyte extends pollen tube carrying 2 sperm toward the egg for fertilization (double fertilization in angiosperms)
When does pollination occur? When does fertilization occur?
Pollination occurs when pollen lands on the stigma
Fertilization occurs after the pollen tube inserts the two sperm into the ovule or ovary
What is double fertilization (only angiosperms)?
– One sperm fertilizes the egg to become an embryo
-One sperm fuses with another gametophyte tissue to form endosperm
-ovary integument becomes seed
What is the ecological advantages of seeds?
– Adaptation to reproduce on lan
– Seeds can remain dormant in soil until favorable conditions
– Improved dispersal
– Stores food
– No need for water for sperm to reach egg
What are the major critical innovations shared by all seed plants?
What does pollen do?
Allows seed plants to disperse male gametophytes
What do ovules do?
Provide protection and nutrition to female gametophyte and embryos
What do seeds allow plants to do?
Allow plants to reproduce in diverse habitats
What does wood do?
Strengthens plants allowing them to grow tall
What innovation of seed plants allows them to grow tall while still being ale to transport nutrients greater distances?
Vascular cambium that makes wood and inner bark
What are the critical innovations of conifers?
-Scales or needle shaped leaves
What are the critical innovations of angiosperms?
What makes gymnosperms unique?
-Produce seeds that are exposed rather than enclosed in fruits
-good at coping with climate changes and living in cold and dry habitats
What is wood?
-tissue composed of water conducting sells strengthened by lignin
-vascular cambium produces wood and inner bark use for transporting water
What were the early gymnosperms?
-Reproduced by spores
-wood came before seeds
What are the characteristics of Cycads?
Emit odors to attract beetles to pollinate
What are the characteristics of Ginkgos?
Ginkgo biloba last species
-humans the ones who ensure survival
What are the characteristics of Conifers?
-Pollen cones and Ovule cones
Pollen wind dispersed
-Some conifers require scarification (attract birds) for dispersal
Wood contains tracheids for water transport and resin ducts to prevent pathogens
Conical shaped, needle leaves, thick waxy cuticle