Chapter 25/26 Flashcards
Green Algae
Live in freshwater habitats and are close relatives to land plants
Land PLants
Terrestial habitats
Why do we study plants?
we rely on plants for food, fuel, textiles, forestry, and horiculture
Ecosystem services
Things that contribute to the environment such as carbon cycle, help prevent erosion, increase h2o Prescence in soil, moderate climate.
Artifical selection and examples
Selecting for traits that are good and farming it.
maize is a good example because it only had a few kernels 100s of years ago and now it has thousabnds of kernels.
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Why is it important that plants are primary producers
Allowed
Human uses for plants/algae
Medicine, Buildings, fuel
How did we go from algae to plants?
- Tides brought in aglae in tide pools and due to tides going down it can create a selective pressure to survive in an non aqeuous environment.
- Plants were seedless initially, but due to the new land and no natural predators, competition induces changes like vascular systems etc.
Advantages of plants on land
More access to CO2 & sunlight, Not as much predators, more room to spread (because it initally had no life)
Why are we still interested in algae
ask prof goff.
lichens
Symbiosis between green algae and fungi
adaptations to countact living on land
cuticles: waxy surface that pervents H2O from leaving
Stomata: allows exchange of gas
Flavonids: UV abosrbing compounds
Why did plants grow tall?
Initally plants were close to the ground because there was more moisture in the ground than in the air. Competition for space and sunlight made plants want to grow tall and vascular systems were the solution
Big four plants morphologies
moss, ferns, gymnosperms, angiosperms
Vascular tissue in 4 morphologies
-moss has simple water conducting cells that had no additions in the vascular system
-ferns had lignin deposit rings that helped strucuture and water movment up
-gymnosperms has a primary wall with cellulose and a secondary wall with lignin with pores that created a vacuum
-angiosperms Has basically the same as gymnosperms, but have ends with perforations that created a stronger vacuum
Chronology of 4 major morphologies
moss<ferns<gymnosperms<angiosperms
How to tell all morphologies apart
moss: nonvascular, uses spores for reproduction, special cells for h2o and nutrient conduction
Ferns:developed vascular tissues, uses spores
Gymnosperms: naked seeds, vascular tissue
Angiosperms: encased seeds, vascular tissue, flowers
What is so important about nonvascular plants (moss)
all key lineages involve with nutrient enrichment, mosses form peat which is an nutrient rich soil of dead plant matter
How do mosses and ferns reproduce?
Alternate generations from gametophytes and sporophytes
Proliferation of land plants
Spores are resistant to many environments\
gametes create genetic diversity
embryos retained and nourished by parent plant
What is moss
A collection of stalks
Antheridium
Sperm producing structures
Archegonium
Egg producing structures
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homosporus
all the same type of spores
heterospores
2 different types of spores
Microsporangia
produces microspores–>male gamete–>sperm
Megasporangia
produces megasproangia–> female gametes –> eggs
How did angiosperms take over?
Success attributed to reproduction organs (flowers), other organism rely on their population to survive, some of those organisms are involved in the reproduction cycle
Stamen
contains, microsporangia in angiosperms (pollen)
Carpel
contains ovary, megasporangia
Double fertilization
2 sperm fuses to make a triploid tissues, creates a nucleous that becomes an endosperm
endosperm
The nutritive tissues (like a yolk) that create enough energy to provide a developing plant to grow vascular tissues, roots, and atleast its first leaf
Monocot
one cotyledon
Euidicots
two cotyledons
Differences of monocots and dicots
Vascular tissue: monocots have scattered tissuse spread out, while dicots have it throughout the stem
Veins: monocots are parallel while dicots are branching
Flowers: monocts have pairs of 3 while dicots have pairs of 4 or 5
Intercalary meristen
if a part of a leaf gets cut they can regenerate instead of dying
The importance of pollen
creates a mutually beneficial relationship between organisms and the plant that causes adaptive radiation and coevolution
Coevolutions
the infulence of species have eachother on an evolutionary scale (bees and pollen)
Adaptive Radiation
many new species from one base species
