Midterm 2 Flashcards
What kinda tree is the tallest?
redwood
What is the oldest type of tree?
bristlecone pine
What is the biggest tree?
sequoia
What is the green revolution?
When major progress made around the 1950-60’s with fertilizers, irrigation, etc. – worried it maxed out agricultural products
What are the 2 definitions of a seed?
- a mature, fertilized ovule that acts as a dispersal unit for seed plants
- contains an embryo, food source and seed coat (testa)
What is 2n composed of?
diploid, 2 chromosomes each composed of 2 alleles (4 alleles total – allele = version of a gene)
What is n composed of?
haploid, 1 chromosome
What is the sporangia
aka “mother cell”, is a sexual organ where meiosis occurs to produce spores (n)
What is the alternation of generations life cycle?
alternation between a haploid (n) gametophyte phase and a diploid (2n) sporophyte phase in the life cycle of a sexually reproducing plant (circle of gametophyte to sporophyte)
What is a gametophyte?
the haploid gamete producing phase in the life cycle
Formed in sexual organs (antheridia / archegonia) – reproduces sexually – undergoes mitosis
Whats the difference between a gamete and a spore?
spore: germinates and develops into a sporeling
gamete: combines with another gamete to form a zygote
What is a sporophyte?
the diploid spore producing phase in the life cycle – reproduces asexually – undergoes meiosis
Bryophytes (gam/spo dominant, homo or hetero)
small, non vascular plants (mosses, liverworts and hornworts) – gametophyte dominant – homosporous
Ferns (gam/spo dominant, homo or hetero)
sporophyte dominant – homosporous
Gymnosperms aka seed plants (gam/spo dominant, homo or hetero)
sporophyte dominant – heterosporous
What is homospory?
the production of one type of spores asexually (same size and type)
What is heterospory?
the production of 2 different types of spores asexually (2 sizes and 2 sexes)
Conifer characteristics
Seeds are in cones (naked seeds)
Cones = a collection of reproductive structures on a short axis
2 types of cones on the same tree (pollen male cones and seed female cones)
What are pollen cones?
many microsporangia that produce microspores which become microgametophytes (pollen) – have 2 air sacs (air bladders) on either side that help with wind distribution (reduce density) – pollen consists of 4 nuclei and is dispersed only through wind
What are seed cones?
each woody scale on the cone has 2 wings and 2 seeds (ovule = seed before fertilization)
Ovule characteristics
Surrounded by integument (2n - tough) Has 2-5 archegonium, each with their own egg (n) (only 1 seed in total carries on tho) Female gametophyte (n) acts as the food source
What are serotinous cones?
require heat to open and release seeds (resin glues it together)
Clears the landscape so lots of sunlight
Provides lotsa nutrients (ash) in the soil to grow
Yews and juniper berry special characteristics
have individual seeds surrounded by a red fleshy aril (part of the seed coat) // juniper berries are fleshy seed cones, not really berries or fruits
What are the big 3?
wheat, corn and rice
What is the hilum?
basically the belly button, where the ovule was connected to the ovary
What is the cotyledon?
they are food storing organs
What does the coleoptile enclose?
plumule
What encloses the coleorhiza?
radicle
What is the pericarp?
Meso, endo and ecto
What is the endosperm?
primarily composes seed, where food is stored (starchy)
What 3 things does germination require?
temperature, water and oxygen
Why isn’t sunlight important?
only certain plants require it to germinate since they can use the food stored in the seed
What is desiccation and why do seeds do it?
it allows them to stay viable during unfavourable conditions, like a “sleeping” dry stage
What are the 3 stages of germination?
- imbibition (absorb water)
- Lag phase (repairs damage done by desiccation)
- Radicle emergence (when the radicle breaks through the seed coat and concludes germination)
What is dormancy?
a period of growth inactivity in seeds or buds, even when environmental requirements for germination are met – used to assure the seeds will germinate at the proper time, often times in the spring
What are 2 ways to break dormancy?
mechanical breaking of the seed coat (scarification) or by cold temperatures – chilled and moist (scarification)
What is the definition of genetics?
the study of how traits are inherited from one generation to the next
What are genes?
make up chromosomes, they are coding DNA
What is the genetic code
set of rules that translate nucleotide sequence into amino acid sequence
How many codons do humans and plants have?
10 for humans, 20 for plants
What does it mean that plants are polyploid?
they have homologous chromosomes (whereas humans/mammals are diploid)
What is the law of independent assortment
that 2 traits determined by 2 genes are passed to offspring independently of each other (Mendel – not accurate)
What are quantitative traits?
show continuous variation – determined by several genes and are influenced by the environment
What is the definition of adaptation?
the process and the product of natural selection
What is an adaptive trait?
structural or physiological – heritable and maximizes fitness (ex. C4 plant)
What are provenance trials?
common garden experiments (helps pick planting stock that is well adapted to local growing conditions) (when you compare different versions of a plant under the same environmental conditions - shows genetic and environmental variation on the phenotype)
What are 3 ways of modifying plants?
Traditional breeding
Transgenic plants
Genome editing in the future tho
What is plant breeding?
accelerated evolution guided by humans, rather than nature
What is green revolution and who was the father of it?
Norman borlaug was father of it
Stem rust fungus (in Mexico) – find one resistance and cross with a local breed – made them self sufficient in wheat production
What does breeding depend on (for plants)?
genetic diversity
What do gene banks do?
they preserve agricultural diversity (dried seeds or frozen plant parts to provide that genetic diversity)
What are transgenic plants/
produced by inserting genes from virtually any organism into plants (to introduce resistance to insects and herbicides - roundup ready crops that are resistant to round up herbicide that suppresses weeds)
What are the inserted genes of transgenic plants called/
transgenes
What is agrobacterium?
soil bacterium, inserts T-DNA that contains gene of interest from its plasmids into plants chromosomes
What helps to clone a gene (produce a transgenic plant)?
e coli that’ll mass produce the gene of interest
What are particle guns?
shoot DNA on gold particles into plant tissue
What is the definition of taxonomy?
describing, naming and classifying organisms (oldest branch of plant study)
What is nomenclature?
a system of naming objects
What is a taxon?
a taxonomic group at any level in the hierarchical system
What is a monophyletic group?
includes all the descendants of a particular common ancestor and the ancestor itself
What is the language of science?
Latin
What is the binomial system of nomenclature?
all living organisms are given 2 word latin scientific name (a species name – one scientific name in latin, many common names to the same species)
How does the binomial system of nomenclature vary from varieies?
varieties have 3 parts to their name (subspecific – trinomen) whereas binomical naming only ever has 2
Who was Carolus Linnaeus? (x2)
Published species plantarum (the starting point for naming vascular plants)
Developed latin names for organisms
Abbreviated names to 2 parts (binomials)
Little letter at end of name = who named it (if L it’s probably Linnaeus)
What is the starting point for naming vascular plants?
the species plantarum
What are cultivars?
arise from human activity (are created by humans)
What would you use to name wild species?
the international code of botanical nomenclature
What would you use to name cultivated plants?
international code of nomenclature for cultivated plants
What are 2 rules for naming a new species?
A unique name and description must be published (latin + genus)
A type specimen of the new taxon must be deposited in a herbarium and available for study for anyone interested
What is a type specimen?
a preserved (dried) plant that is typically deposited in a herbarium (a collection of preserved plant specimens)
What are some features about taxonomic keys?
they are used to aid in the identification of organisms Mostly dichotomous (presented with a pair of choices for different character states of a character or feature of the organism)
What are closely related species grouped together called?
genera (aka genus)
What is the order from variety to kingdom?
Kingdom - Phylum - Class - Order - Family - Genus - Species - subspecies/variety
What is the most fundamental level of classification and what is its definition?
species: a set of individuals closely related by descent from a common ancestor
What was the most significant event in evolution?
the origin of life 3.5 billion years ago
What are the 6 kingdoms?
animals, fungi, plants, protists, archaea and cyanobacteria
What are the 3 domains?
bacteria, archaea and eukarya
What are protists?
A very broad group (includes lotsa organisms)
Not monophyletic and not a natural kingdom
Probably will be broken down in the future
What are cyanobacteria?
prokaryotes that have chlorophyll, produce oxygen and fix nitrogen
How might chloroplasts have originated?
as cyanobacteria living within other cells
What is a clade?
it shares one common ancestor
What does polyphyletic mean?
derived from more than one ancestor (unrelated) lack a most recent common ancestor
What does paraphyletic mean?
consists of the most recent common ancestor and some of its descendants
What does monophyletic mean?
consists of the most recent common ancestor and all of its descendants
What do phylogenic trees (evolutionary trees) consist of?
monophyletic groups
What do bryophytes include?
mosses, liverworts and hornworts
What do plants have in common with green algae?
chloroplasts a and b, carotenoids, starch and cellulose
What differentiates plants with green algae?
plants grow on land, algae in the water and plants release embryos with a parental tissue surrounding them for protection, whereas algae doesn’t
How do bryophytes reproduce?
sexually but need water for it
What are some features of mosses?
have antimicrobial properties, acidify water around them, damage to peatlands can release a lot of carbon into the atmosphere, increase water retention of soil since they have hollow cells that allow for water storage in between photosynthetic chlorophyll cells
How do gemma cups work?
they allow certain bryophytes to perform asexual reproduction and distribute with rain
What are gemmae?
small discs of tissue growing into new gametophytes
Why are bryophytes often small?
they have no vascular tissue (no xylem or phloem) or roots so no circulatory system
How does coal originate?
it comes from organic plant matter
Features of seedless vascular plants
ferns and their relatives – they have true roots and stems
Features of lycophytes
Can get very tall since they have vascular tissue (KEY)
Heterosporous (2 types of spores)
Features of horsetails
Scale like leaves (whorled)
Stems do photosynthesis
Sporangia at the tip of some stems
Can be a weed
Features of ferns
Fronds are often large and much divided Vascular, free sporing and homosporous The underground stem = a rhizome Most abundant in tropical regions but also found in cooler climates Sporangium act as a catapult
Conifer features
Narrow tracheids so they are freeze resistant
Needles: have thick cuticle, sunken stomata and endodermis
Trees or shrubs (most are evergreen)
Resin canals
Stress tolerant
Susceptible to bark beetles when stressed
What is part of the cypress family?
junipers and redwoods
What is the largest family of conifers?
pine family
Ginkgophytes features
one living species left, living fossils (VERY OLD), male and female trees, deciduous
Gnetophytes features
Grow in very dry conditions Use fog moisture / condensation for water CAM photosynthesis Some are very old Looks old and scraggly
Angiosperm features
Monophyletic (1 common ancestor)
Ovules are enclosed in an ovary (gymnosperms = naked)
Ovary becomes a fruit
Use double fertilization, creates a 3n endosperm
Have flowers that provide lots of interactions with animals
Have sieve elements, companion cells and xylem
Roses features
Flowers attract bees, insect pollination
Many with edible fruits
Many ornamental trees and shrubs
Lilies features
Monocot, herbaceous
Large flowers with their parts arranged in threes
Grow from bulbs
Beautiful ornamental plants
What is the reaction for photosynthesis and respiration?
Energy + Co2 + H2O = C6H12O6 + O2
Going right is photosynthesis, going left is respiration
What is the endosymbiosis theory?
When a free living cyanobacteria was engulfed by a larger cell (also prokaryotic) to form a symbiosis where cyanobacteria does photosynthesis within larger cell (large cell benefits) – cyanobacteria turns into a chloroplast – then to green algae and plants
How do plants sense light?
with photosynthestic pigments (ex. chlorophyll)
How do seeds detect light?
with phytochrome
What are blue light receptors?
located in stomata – sense light in the early morning and take up carbon dioxide from the atmosphere
What light has higher energy?
blue has higher energy than red light
What did einstein state about light?
light is composed of particles of energy called photons
How do pigments work?
they absorb certain wavelengths (colours) and reflect others
What is colour?
what an object or something reflects
Why are carrots orange?
because they absorb green/blue lights but reflect red/orange/yellow lights
What are carotenoids?
accessory pigments in photosynthesis (that help chlorophyll absorb light), absorbing wavelengths that chlorophyll doesn’t (helpers)
Roles in antioxidants
Roles in photoprotection
Bonds are double then single then double then single…. (alternating)
What is the principal pigment of photosynthesis?
chlorophyll
Where is chlorophyll located?
in the thylakoid membranes of algae, cyanobacteria and plants
What 2 fancy elements do chlorophyll require?
nitrogen and magnesium
What is the difference between a and b chlorophyll?
they have different absorption peaks
What is the purpose of hydrophobic tails for chlorophyll?
to help anchor them in the thylakoid membrane
What do chlorophyll rings do?
absorb energy
What are the 3 things that might happen when chlorophyll returns to its ground state?
fluorescence, energy transfer or electron transfer
What is fluoresence?
when excited chlorophyll returns to ground state and emits photon of lower energy and a bit of heat (lower E = longer wavelength)
What is energy transfer?
When it passes energy to a neighbouring chlorophyll molecule (only works when they’re close together) – electron becomes excited in an excited state – occurs in photosynthesis
What is electron transfer?
in photosystems of light reactions (is a chemical reaction), loses electron to an acceptor molecule and starts a light reaction – occurs in photosynthesis
How does a light reaction occur?
starts at photosystem 2 in the thylakoid membrane, then electron transfer to electron acceptor then the light reaction occurs
What do photons do (x3)?
- have energy
- cause electrons to become excited
- excite chlorophyll
What are anthrocyanins?
provide photoprotection during the breakdown of chlorophyll (hypothesis)
Red pigments
Where are chloroplasts located?
in the mesophyll
Where does photosynthesis occur?
in the leaf within the thylakoid membrane
What 2 things are photosystems composed of?
reaction center and antenna pigments
What is the reaction center?
where electrons are passed on (in membrane so they can be packed tightly together so they can transfer the electrons)
What does NADPH do?
its an electron transporter
Where do light reactions occur?
in the thylakoid membrane
How is ATP created in photosystems?
when electrons flow from the thylakoid membrane out into the stroma