Plant Biodiversity Flashcards
what are charophyceans?
closest algal relatives to plants
what is the advantage of sporopollenin?
prevents exposed zygotes from drying out so aided in the evolution of land plants
what is the monophyletic group name of land plants?
embryophytes
how many times did embryophytes evolve and what from?
the evolved only once and from freshwater aquatic multicellular algae
what are 4 traits shared between land plants and charophyceans?
1) rose shaped complexes for cellulose synthesis
2) peroxisome enzymes
3) structure of flagellated sperm
4) formation of phragmoplast in cytokinesis
what are 5 problems with moving from aquatic habitats to land?
1) water balance
2) availability of nutrients and gases
3) support
4) UV protection
5) reproductive strategy
what are the 2 main clades of land plants?
1) bryophytes
2) tracheophytes
what are features of bryophytes?
- non vascular plants
- gametophyte dominant
what are features of tracheophytes?
- vascular plants
- sporophyte dominant
3 non vascular plants?
1) liverworts
2) mosses
3) hornworts
3 types of vascular plants groups?
1) free sporing plants
2) angiosperms - flower seed plants
3) gymnosperms - seed plants
what are apical meristems?
localised regions of cell division - help growth of root and stems
explain alternation of generations?
multicellular haploid (gametophyte dominant) and multicellular diploid (sporophyte dominant) stages of the lifecycle
what is the job of the sporangium?
protects developing spores from harm
what are the male and female reproductive organs called?
1) archegonia - female
2) antheridia - male
why are land plants called embryophytes?
they have multicellular dependent embryos with placental cells that transfer nutrients from parent to embryo
what are bryophytes reproductive strategy?
they are homosporous
what are the 2 main things which make up a bryophyte gametophyte and how are they anchored?
1) gametophore
2) protonema
anchored by rhizoids
what does a bryophyte sporophyte consist of and what are their jobs?
1) a foot - absorbs nutrients from parental gametophytes
2) a seta - conducts materials to sporangium
3) a sporangium - produces spores by meiosis
what is a calyptra?
protective cap for sporangium which is shed when sporangium is mature
what is a peristome and its job?
tooth like structures for gradual spore discharge
which sporophytes have stomata for gas exchange?
mosses and hornworts
what are isospores?
spore exhibiting no sexual dimorphism
how are mosses able to live in extreme habitats?
they can survive loss of most of their body water and rehydrate when water is available so can live in cold or dry habitats
what is the benefit of phenolic compounds in mosses cell walls?
absorb damaging levels of radiation
how do peat bogs prevent decay and what do they store?
low nutrients and temperatures and they store organic carbon
what are the most primitive extant vascular plants?
lycopsids
why are tracheophytes more adapted for life on land than bryophytes?
because the sporophyte stage is dominant over gametophyte stage and sporophyte has lignified conducting tissues providing support
are lycopsids homosporous or heterosporous?
both
what is the job of the xylem and phloem?
xylem conducts most of the water and minerals
phloem has living sugar conducting cells and transports amino acids
what are tracheids?
tube shaped cells that carry water and minerals up from the roots
what are the 2 most abundant polymers in plants?
1) cellulose
2) lignin
what is the difference between microphyll and megaphyll leaves ?
microphylls - spine shaped leaves with single veins
megaphylls - highly branched vascular system with much greater photosynthetic activity
what are sporophylls?
modified leaves that bear sporangia
what is an advantage of heterosporous plants?
due to the megaspore and sperm needing to land near each other which has low probability it encourages outbreeding which speeds up evolution and it doesn’t need damp to reproduce so opens up more land habitats
what are 4 points of significance of seedless vascular plants?
1) formed first forests in carboniferous period
2) increased photosynthesis = removal of CO2 = global cooling
3) formed peat bogs which drove the industrial revolution and ice age world into greenhouse world
4) end or permian arborescent lycopsids became extinct leaving herbaceous forms present today
