Lecture 1 -- Plants Flashcards
Why are plants important
they give us energy by providing us with food, (agriculture), fossil fuels, drugs, biodiversity, clothes
What is Botany
the study of plants
what is a plant
many ways to define this, in this class, we focus on streptophytes and chlorophytes.
what are streptophytes
charophytes and embryophytes.
what are embryophytes
land plants
what is a plastid
organelle in a cell that use to be free-living bacteria (cyanobacteria) – now lives in a symbiotic relationship with eukaryote.
photosynthetic eukaryotes include
plants (and also green algae) and red algae.w
hat are other eukaryotes
non photosynthetic eukaryote engulfed a photosynthetic prokaryote )red/green algae)
major events in plant life history
4550 MYA the earth formed.
3500 MYA photosynthesis appears
1500 MYA 1st plastid; plants and red algae diverge.
500 MYA colonization of land by plants, fungi, then animals.
colonization of drier environments
organisms invaded land to allow organisms to live on land. adaptations were: cuticles, vascular tissue: roots and shoots, relationship with fungi, and seeds & pollen.
Ancestors of plants/land plants
features of all plants
starch as main energy-storage molecule, chlorophyl b, cellulose major component of cell wall, thylakoids in stacks (grana)
features that differ between streptophytes and viridiplante
charophyte is the closest relative to land plant, evidence by anatomical structures, and both have nuclear and chloroplast DNA. They have cel plates and phragmoplast which are short microtubules, they have plasmodesmata, which is the connection between cells, also referred to as tunnels. their sperm structure, peroxisome enzymes, rose shaped cellulose-synthesizing complex and sporopollenin.
why did plants move to land
because more sunlight was available, more CO2, early habitats lacked the predators now seen, and soil is richer in nutrients.
what do ONLY land plants have
cuticle waxy covering, multicellular jacketed sex organs (gametangia), embryophyte condition, alternation of generations
what is an embryophyte condition
this is where the zygote is maintained in the maternal tissue.
what is alternation of generations
both haploid and diploid stages are multicellular, the two generations are sporophyte and gametophyte.
gametophyte stage
haploid stage multicellular that makes gametes by mitosis.
sporophyte stage
makes spores by meiosis diploid stage multicellular
how did alternation of generations generate
zygote delays meiosis and divides and grows. – resulting in a multicellular diploid. it arose independently in evolution, and does NOT occur in charophytes. ONLY embryophytes.
oxygen revolution
occurred 2400 MYA. cyanobacteria caused oxygen revolution to occur as photosynthesis started with them 3500 MYA, then 700 MYA it is said plants occurred because of the increased amount of oxygen.
what are some examples of why plants are important
agriculture: chocolate,
gas was a plant,
rubber comes from trees,
cotton for clothing,
drugs are plants secondary components, aspirin, caffeine,
what does it mean by plants secondary components
not used in photosynthesis but are used to ward off insects, parasites, etc.
cardinal flower
pollinated by humming birds, attracts humming birds because of its reward (nectar) and advertisement (red colour).
what do the humming birds do with pollen
they can either transfer pollen from one plant to another or transfer pollen on one single plant.
structure of plant
male flowers are at the top which are younger, and the female flowers are at the bottom, which are older.
what groups are in viridiplante
embryophytes, charophytes, and chlorophytes.
what is an antheridium
male sex organ, produces sperm, haploid
what is an archegonium
female sex organ, produces egg, haploid.
draw the life cycle of chlamydomonas.
should have a 2n stage consisting of the zygote, it’ll undergo meiosis producing 4 offspring, 2+ and 2- those are in the 1n stage, mitosis in these gametes will occur, fertilization, boom zygote again.
