Midterm Flashcards
What are the three plant organs?
Roots, stems, and leaves
What is the primary function of roots?
Anchor the plant, absorb minerals and water, store carbohydrates
What are some specialized functions of roots?
Support, obtaining oxygen, storage
What is the primary function of stems?
to elongate and orient the shoot for photosynthesis
What are some specialized functions of stems?
Support, reproduction
What are some examples of stems?
Rhizomes, stolons, tubers, brussel sprouts
What is the primary function of leaves?
photosynthesis
What are some secondary functions of leaves?
Gas exchange, heat dissipation, defense from herbivores and pathogens
What are some specialized functions of leaves?
Defense, reproduction, storage, movement
What are some examples of leaves?
spines, tendrils, plantlets, onions
What are the three types of plant tissues?
dermal, vascular, ground
What is the main function of dermal tissue?
protection and reduction of water loss
Describe ‘periderm’
the protective layer of dermal tissue that replaces the epidermis in woody plants
Describe ‘cuticle’
a part of the epidermis that prevents water loss
Describe ‘trichomes’
a dermal tissue that reduces water loss, reflects light, and defends against insects
What is the main function of vascular tissue?
to transport materials and provide mechanical support
What is the main function of xylem?
to conduct water and dissolved minerals upward
Describe ‘tracheids’
a type of xylem that has long thin walls with tapered ends and thin regions lacking secondary walls called pits through which water moves
Describe ‘vessel elements’
a type of xylem that has end walls with perforation plates so water can flow freely
What is the main function of phloem?
transport sugars from production areas to storage/growing areas
What kind of plants have sieve cells? What kind of tissue are they?
Seedless vascular plants and gymnosperms, phloem
What kind of plants have sieve tubes?
angiosperms
Describe ‘sieve tubes’
chains of cells called sieve-tube elements whose porus end walls between them (sieve plates) allow for fluid to flow between cells
Each sieve-tube element is connected to a companion cell (that has organelles) by plasmodesmata
What are some functions of ground tissue?
storage, photosynthesis, support, transport
What are the three types of ground tissue?
Parenchyma, collenchyma, and sclerenchyma
Parenchyma, collenchyma, sclerenchyma, or multiple -> supports herbaceous plants
collenchyma and sclerenchyma
Parenchyma, collenchyma, sclerenchyma, or multiple -> has a large central vacuole that can be used for storage
Parenchyma
Parenchyma, collenchyma, sclerenchyma, or multiple -> made up of sclereids and fibers
sclerenchyma
Parenchyma, collenchyma, sclerenchyma, or multiple -> perform the most metabolic functions
Parenchyma
Parenchyma, collenchyma, sclerenchyma, or multiple -> provides flexible support without restraining growth
collenchyma
Parenchyma, collenchyma, sclerenchyma, or multiple -> retains the ability to divide and differentiate
Parenchyma
Describe ‘sclerids’. What kind of ground tissue are they?
short and irregular with thick, lignified secondary walls
Sclerenchyma
Describe ‘fibers’. What kind of ground tissue are they?
long, slender, and arranged in threads
Sclerenchyma
What are the two major types of plant meristems?
Apical and lateral
What is the general function of apical meristems?
elongate shoots and roots, prevent the growth of lateral branches/axillary buds
What do apical meristems produce?
Produce protoderm (dermal tissue), ground meristem (ground tissue), and procambium (vascular tissue)
What two things make up lateral meristems?
vascular cambium and cork cambium
What is the function of a root cap?
cover the root tip to protect the apical meristem
What are the three zones of root growth?
Cell division
Elongation
Differentiation/Maturation
Describe ‘pericycle’
Lateral roots arise from the pericycle that surrounds xylem/phloem
Describe what you would see in a root cross-section of a eudicot
xylem and phloem in the center, the xylem is arranged in a star with the phloem around it
Describe what you would see in a root cross-section of a monocot
a core of parenchyma cells surrounded by a ring of xylem, and phloem (looser arrangement)
What protects the apical meristem>
the leaves of the apical bud
Where do axillary buds develop from?
meristematic cells left at the bases of leaf primordia
Describe what you would see in a stem cross-section of a eudicot
a vascular bundle forming a ring around the edge of the stem, that goes pith-xylem-phloem-fiber cells-cortex-eipdermis
Describe what you would see in a stem cross-section of a monocot
mostly ground tissue, with vascular bundles scattered throughout
Describe the function and arrangement of stomata
Stomata are pores in the epidermis that allow gas exchange
Major avenues for evaporation loss (so most are on the lower side)
Describe the function of guard cells
guard cells control the opening and closing of stomata
What is the general type of tissue between the upper and lower epidermis of plants? (tissue type, cell type, name)
ground tissue -> parenchyma ->mesophyll
Describe the bilayer arrangement of the tissues between the upper and lower epidermis in eudicots
There are two layers in eudicots: the palisade in the upper part and the spongy in the lower part (loose arrangement for gas exchange)
Palisade is lined up in rows
What are the two functions of leaf veins?
vascular bundles and skeleton
Describe ‘bundle sheath’
a protective layer that encloses leaf veins
What three tissues could make up secondary xylem?
tracheids, vessel elements (angiosperms), and fibers
Describe ‘heartwood’
older layers of xylem that no longer function
Describe ‘sapwood’
outer layers of xylem that still transport materials
What happens with older secondary phloem?
sloughs off
What is the direction of secondary growth of xylem and phloem?
Xylem is towards the core, phloem is towards the outside
Describe ‘early wood’
formed in the spring in temperate regions and has thin cell walls to maximize water delivery
Describe ‘late wood’
formed in the summer and has thick cell walls for support
How do tree rings form?
Tree rings are visible where late and early wood meet and can be used to estimate a tree’s age
Describe ‘dendrochronology’
the analysis of tree ring growth patterns and can be used to study climate change
Thick rings indicate a warm or wet year
Thin rings indicate a cold or dry year
What is the function of the cork cambium?
Replaces the epidermis with periderm (towards the outside)
Describe the life cycle of cork cells
Cork cells accumulate to the exterior of the cork cambium
They deposit waxy suberin in their walls, then die
Describe ‘phelloderm’
the thin layer of tissue produced on the inside of the cork cambium in woody plants that forms a secondary cortex
Describe ‘prop roots’
found in plants that grow very tall and need support
Describe ‘pneumatophores’ (hint: a type of root)
grow in waterlogged soil to get oxygen to roots
Describe ‘strangling aerial roots’
a seed lands in a host tree and envelopes it
Describe ‘buttress roots’
when trees have shallow roots or are in humid climates
How can you detect a phase change in a plant?
The morphological changes in leaves that occur during phase changes from a juvenile phase to an adult vegetative stage to an adult reproductive stage can be used to detect phase changes
What are the kinds of water-transporting cells that are dead at functional maturity?
tracheids and vessel elements
Parenchyma, collenchyma, sclerenchyma, or multiple -> unevenly thickened primary cell walls
collenchyma
When was the origin of the earth?
4.6 BYA
When was the first fossils of prokaryotic life? What were they?
3.5 BYA, stromatolites
When were the first animals? What were they?
.7 BYA, sponges
When was the oxygen revolution? Why was it significant?
2.7 BYA, caused the extinction of many prokaryotic groups, others adapted using cellular respiration
How did the first eukaryotes form (basic)? When was this?
1.8 BYA, originated by endosymbiosis with a aerobic bacterium
What were the first multicellular organisms? When were they?
1.4 BYA, small red algae
Most modern animals via the _____ explosion
Cambrian
What were the first colonists on land? When was that?
.5 BYA, plants and fungi as mycorrhizae
What is the edicaran biota?
an assemblage of larger and more diverse soft-bodied organisms that lived from 635 to 541 MYA
Define phylogeny
the evolutionary history of a species or group of related species
Define systematics
the discipline that classifies organisms and determines their evolutionary relationships
What are the the eight levels of the current hierarchical classification? What groups make up the highest level (most broad)?
Domain, kingdom, phylum, class, order, family, genus, species
Three domains: Bacteria, Archaea, Eukaryotes
What are the rules for binomial nomenclature? (parts, format)
The first part of the name is the genus, the second is the specific epithet
The first letter of the genus is capitalized, the entire species name is italicized
Both parts together name the species
What is a phylogenetic tree?
The evolutionary history of a group of organisms
What do branch points on a phylogenetic tree represent?
the divergence of two species
(phylogentic trees) define sister taxa
groups that share an immediate common ancestor
(phylogentic trees) define clade
a group of species (an ancestral species and all descendants)
(phylogentic trees) define outgroup
a species or group of species that is closely related to the ingroup (the various species being studied)
(phylogentic trees) define polytomy
section of a phylogeny in which the relationships cannot be fully resolved (many branches from one point, do not know order of divergence)