Lecture 5: Greening of the Earth Flashcards
Are plants eukaryotes or prokaryotes?
eukaryotes
What are some characteristics of plants?
They are multicellular, photoautotrophs, and they have cell walls made of cellulose
What other “thing” has the same traits as the plant(multicellular, cell wall made of cellulose, and a photoautotroph)?
Seaweed, a protist has all these traits as well
What are some differences between plants vs protist differences?
- all plants multicellular: algae can be unicellular, colonial, or multicellular
- most plants live on dry land, algae live in aquatic or moist habitats
- plants have a waxy cuticle, algae does not
- most plants have roots, stems, leaves, and vascular tissue, algae does not
What is a charophyte?
green algae that is a protist
what are the basic resources plants require in order to survive and reproduce?
water, light, and co2 for photosynthesis, o2 for cellular respiration, mineral nutrients to make dna, proteins, lipids(nitrogen, phosphorous, potassium)
The transition from living in water to living on land provided both benefits and challenges for plants in terms of?
support, resources, and reproduction
What are some benefits for algae to live in water?
- surrounded and supported by water
- access to lights
- can take up nutrients directly from water via diffusion
- gametes released directly into water for easy dispersal
- stable temperatures and humidity
What are some limitations for algae to live in water?
- can only access light near surface
- there are limited amounts of dissolved o2, co2, and minerals
What are some benefits for the first plants to live on land?
- brighter, unfiltered sunlight
- plenty of co2 and o2
- soil rich in nutrients
- the first land plants had less competition and fewer predators
What are some limitations for the first plants to live on land?
- Lack of structural support against gravity
- Lack of water - as a resource and to stop
from drying out ( desiccation ) - Fluctuating temperature & humidity
- Nutrients and water need to be
transported from soil to plant - Modes of reproduction needed to be altered ( to prevent spores from drying out, and for dispersal )
What are derived traits?
unique traits that evolved during the evolution of a specific lineage after the split from the common ancestor with other lineages
What do the derived traits of plants distinguish them from?
close green algae relatives, charophytes
5 derived traits found in all plants but not protists are?
- Alternation of generations
- Embryophytes
- Walled spores made in sporangia
- Multicellular gametangia
- Apical meristems
Alternation of generations?
plant life cycles alternate between gametophyte
(gamete-producing plant) and sporophyte (spore-producing plant): both are multicellular
Embryophytes?
a multicellular plant embryo dependent on the parent
* The developing embryo remains inside the tissues of the female plant
* Get protection and nutrients via specialized placental transfer cells
Walled spores made in sporangia?
sporangia: multicellular organ with the sporophyte plant that produces spores
spores: single reproductive cells that grow into the multicellular gametophyte
What are spore walls made of?
sporopollenin: making the spores extremely resistant to harsh environments
Multicellular gametangia?
- Gametangia: multicellular organ within the gametophyte that produces gametes
Female gametangia: archegonia make eggs and male gametangia: antheridia makes sperm
What is phyte?
plant
Spore/gamete?
reproductive cells
Gametophyte?
plant that produces gametes
Sporophyte?
plant that produces spores
embryo?
developing organism after fertilization
embryophyte?
developing plant
angium?
receptacle/container/organ
gametangia?
organs that make gametes
sporangia?
organs that make spores
apical meristems?
areas of cell division at the tips of roots and shoots: plants on land need resources from above ground and below ground, therefore need to grow up and down
what does plant meiosis form?
spores
are gametes formed before or after fertilization?
before
what does the archegonia make?
eggs
evolution of plants?
as plants continued to adapt for successful life on land, new derived traits emerged. Key adaptation = a notable derived trait that provides an individual with a new
ability that allows it to take advantage of previously unavailable habitats or resources
early evolving plant groups:
fewer adaptations and are more similar to aquatic algae than later groups
later evolving groups:
retain all the key adaptations that arose in earlier groups
byrophytes?
the first land plants are non vascular:including liverworts, mosses and hornworts
what are the key adaptations to these non vascular plants?
waxy cuticles: coats the surface of the plant to prevent water loss/drying out
stomata: pores in the surface that open and close: exchange of co2 and o2 with surrounding air, where water evaporates, close to minimize water loss
what are the byrophytes major limitations?
height is below 20cm, no vascular system or true roots or leaves
no long distance transport of water and nutrients
limited structural support
restricted to moist environments
dispersal by spores: small short distances
vascular plants?
have vascular tissue; systems of tubes that transport water and nutrients throughout the organism.
seedless vascular plants include?
ferns, horsetails, club mosses
what are the two vascular tissues?
xylem and phloem: transport tissues connecting above and below ground and move water and nutrients long distances; the secondary cell walls of xylem also provide support against gravity
leaves?
main photosynthetic organ : increase surface area for light capture
roots?
structures that extend into soil : increase access to water and nutrients in soil, anchor the plant
seedless vascular plants limitations?
- limited to moist environments bc they need film of water for reproduction, spores= limited dispersal
