Study Questions

climate change vs weather

the long term weather conditions in a given place (weather is a much more short term phenomenon)

greenhouse effect

process where atmospheric gasses trap solar heat near Earth’s surface

greenhouse gasses

• carbon dioxide

• water vapor

• ozone

• methane

• nitrous oxide

Eunice Foote

the first person to discover the greenhouse gas effect in 1856

Svante Arrhenius

discovered that humans were adding carbon dioxide to the atmosphere and are causing the planet to warm

radiative forcing

the change in the energy balance of the earth from preindustrial times until the present

positive forcing

caused by:

• greenhouse gasses

• ozone in the troposphere

• surface albedo of black carbon on the snow

• solar energy

• net anthropogenic forcing

negative forcing

caused by:

• ozone in the stratosphere

• surface albedo on the land

• aerosols

uncertainties associated with climate change

• how hot will it get

• the pace of change

• tipping points

two general components of human activity that most effect the climate

the burning of fossil fuels and deforestation

Paris Agreement

an international agreement aimed towards reducing deforestation and decreasing (and ultimately eliminating) the use of fossil fuels made in 2105 with the specific goal of trying not to go 2 degrees celsius above average heating

physical evidence that the earth is heating

• shrinking glaciers

• shrinking arctic and greenland ice caps

• data from ice cores

• rising ocean levels causing nuisance floods due to thermal expansion

• thawing of permafrost in arctic

physical evidence that humans are causing global warming

C₁₂ and C₁₃ are both stable isotopes of carbon but when burning fossil fuels C₁₂ is the emitted carbon, so the ratio of these isotopes has significantly dropped since C₁₂ has increased so much

keeling curve

how much the carbon dioxide has risen in the atmosphere since 1950 from a big volcano in Hawaii; also shows variation due to photosynthesis because plants are dormant in the winter and are not drawing carbon dioxide out of the atmosphere

increasing CO₂ levels’ impact on the ocean’s atmosphere

results in ocean acidification because the pH is falling

ice core data

allows for sampling of atmospheric carbon dioxide levels from thousands of years ago because of their air bubbles

• this set of data overlaps with the keeling curve

what will humans need to do in response to climate change

adapt and mitigate (limit emissions of greenhouse gasses)

two main causes of rising sea levels

• melting of Greenland and Arctic ice caps

• thermal expansion

what are fossil fuels mostly used for

energy production

tipping points

thresholds that once crossed are irreversible

examples of tipping points

• the melting of the Arctic and Greenland ice caps

• thawing of permafrost in the Arctic

what can tipping points lead to

tipping cascades

once on land how did bryophytes adapt

to be desiccation tolerant

• they turn brown and crinkle if there is not enough water to absorb

• it shuts down for a period and turns off metabolic processes

also have high surface area to volume ratio because water is diffused, and not moved efficiently

once on land how did lycophytes, gymnosperms, and angiosperms evolve

the use specialized cells to transport nutrients internally and use roots to take up water from the soil and they have an intercalary meristem to keep it alive from animal grazing

why is meristem tissue important

it allows plants to grow

where is meristematic tissue found

they are found in meristems, and can turn into any kind of tissue the plant needs, just will be limited to a particular location

types of meristem

• apical

• intercalary

• lateral

apical meristem

at the tip of branches near roots and allows the plant to increase in length

lateral meristem

found within branches and increases the girth of the plant so they are thicker

intercalary meristem

found in monocots and is an evolutionary adaptation to heavy grazing so it allows the leaves to increase in length after the ends have been removed, they are at ground level so the blade can regrow

three types of permanent tissue found in vascular plants

• dermal

• vascular

• ground

dermal tissue

covers and protects the plant

vascular tissue

transports water, minerals, and sugars within plant to different parts of plant so the plant can get bigger

ground tissue

mostly found in leaves because site for photosynthesis as it stores water and sugars, and is the supporting matrix for vascular tissue

three major plant organs

• leaves

• stems

• roots

stem

• connects roots to leaves

• transports water, minerals, and sugars made in photosynthesis

• supports the plant

• allows the plant to grow above/block other plants

root

provides stability for the plant by growing into the soil, stores sugars, and absorbs water, minerals, and nutrients from the soil

leaf

provides photosynthesis

three subdivisions of plant tissues in the stem

• parenchyma cells

• calenchyma cells

• schierenchyma cells

parenchyma cells

• most common and found in the stem, leaf, root, and pulp of the fruit

• responsible for metabolic functions (photosynthesis, wound repair, and starch storage)

collenchyma cells

• alive at maturity and are found below the epidermis

• provide structural support (mainly in stems and leaves)

• celery strings

sclerenchyma cells

• mostly dead at maturity

• cell walls are thickened with lignin

• provides structural support

• used for linen and rope

epidermis

type of dermal tissue found in vascular plant

• primary purpose is to provide a barrier between the inside and outside of the organism

• most numerous and least differentiated cell in the dermis

• one cell layer thick

• contains openings called stomatas

• has trichomes

trichomes

on surface of the epidermis, hair like structures used to defend the plant from herbivores and store chemical defenses there

stomata location

found in the epidermis of a vascular plant’s leaves

stomata function

allow for gas exchange of water vapor and carbon dioxide

what allows the stomata to open and close

guard cells

how do guard cells work

they function like balloons

• inflate/swell when ions/solutes and water enter and hold their general shape, keeping the somata open

• when ions/solutes and water flow out, they deflate and overlap, closing the stomata

stem vascular tissues

xylem and phloem

xylem

acts like a drinking straw and carries water in the plant from roots to leaves

• grows together in large tubes at once in necessary place at maturity (they die) and cell walls are reinforced with lignin

• in a monocot they are less organized and dispersed

• in a dicot they are arranged in a ring shape

• tracheids

tracheids

narrow chambers adjacent to vessels and have lignified thick cell walls and are connected to other tracheids via small pits

phloem

transports carbohydrates and minerals from leaves to roots

• the dissolved sugars diffuse from high to low concentration (roots are metabollicly active so have a low sugar concentration)

• tissue is alive at maturity

• sieve tube cells

• companion cells

sieve tube cells

arranged end to end with sieve plates connecting their cytosol

companion cells

alongside sieve tube cells and have extra ribosomes and mitochondria to provide sieve tubes with metabolic support

root anatomy

• root cap

• root hairs

• casparian strip

root cap

an area of rapid cell replacement from where cells are damaged by burrowing into the soil, like a bumper to resist pressure of sediment pushing back on root

root hairs

extensions of the root epidermis to maximize surface area for water absorption

casparian strip

facilitates vitamins and minerals

• waxy tissue layer at the outer edge of the endodermis in the root

• forces active transport of water and solutes to enter phloem and xylem

• designed to be completely impermeable and everything that goes across it must be actively transported (why roots are so metabolically active)

parts of a leaf

• tip

• midrib

• margin

• vein

• petiole

• lamina

tip

narrowest and furthest point from the stem

midrib

carries sugar out and water in

margin

identifies species of plant (smooth, jagged, etc)

vein

supplies water and takes up sugar from leaf edge

petiole

exports sugar and imports water

lamina

makes up leaf’s surface area, non vascular part of the plant

three layers of leaf

• upper epidermis

• mesophyll

• lower epidermis

there is cuticle on both ends, just less on the bottom because do not want to get in the way of guard cells/stoma

upper epidermis

one cell layer and prevents sunlight from getting into the next layer

mesophyll

has two distinct layers of parenchyma cells

• palisade

• spongy

palisade parenchyma

responsible for photosynthesis, actively takes up carbon dioxide during the day and undergoes cellular metabolism at night

spongy parenchyma

loosely organized to allow gas exchange which provides support and structure to the leaf and excretes oxygen as photosynthesis byproduct

lower epidermis

contains the stoma to allow for gas exchange

what are stoma driven by

water conversion, because once open the water steams out at a very fast rate, but carbon dioxide still needs to be let in

what adaptations did plants make to survive on land (no longer in marine environment)

seed plants evolved to have their sperm be transferred airborne (pollination)

pollen

airborne sperm that is carried to the ovule by wind or pollinators

stamens

the reproductive shoots that are specialized for transferring and receiving pollen

how does alternation of generation work

plants alternate between haploid and diploid in each generation

parts of the plant cycle that are haploid

also known as the gametophyte generation

• haploid spores are released into the environment

• the spore undergoes mitosis to grow into gametophyte

• the gametophyte (haploid plant) produces gametes to make reproductive cell (egg or sperm)

• the reproductive cells merge and undergo mitosis to form a zygote

parts of the plant cycle that are diploid

also known as the sporophyte generation

• sporophyte is diploid reproductive tissue that undergoes meiosis to make haploid spores

• diploid zygote grows/undergoes mitosis to become adult diploid

what generation is dominant in seed plants

diploid, the haploid is completely encased in the diploid reproductive tissue

different mechanisms of pollinators used by seed plants

being transported by external forces

how is pollen/the male sperm released

in massive quantity very easily

male vs female cones

male cones are on the lower branches and have a much less protective shell, that can be easily bumped and release pollen

what did flowers and pollinators form and how does it work

a symbiotic relationship, and flowers have evolved to further attract pollinators

gymnosperm pollination

1) formation of two spore types

2) spores undergo mitosis

3) pollination

4) maturation of ovule into seed

formation of two spore types

each haploid spore type is produced in separate sporangia (diploid)

spores undergo mitosis

inside sporangia where they form the gametophyte

pollination

lands on receptor and buries through the scale forming a pollen tube to the ovule to fertilize the egg

maturation of ovule into seed

gymnosperm has 3 generations in one structure:

• diploid seed coat is like grandparent and is a hard shell/protective coating

• haploid female gametotype is like the parent and has spores inside, so is an energy source for the embryo

• diploid embryo is like grandchild and forms when the female ovum is fertilized by pollen

angiosperm pollination

normally have male and female reproductive parts on the same flower

• pollen lands on the stigma

• pollen tubes grow through the style and the pollen fertilizes/merges with ovary in sporangia

perianth

whole flower

• corolla

• carlyx

corolla

composed of petals which are specialized leaves for reproduction to attract pollinators (very vibrant and patterned to them

calyx

composed of sepals which is a specialized protective leaf that keeps the flower safe while it is developing, once flower is mature, it pulls back and lets it fully bloom

pistil

the female reproductive tissue

carpels

the whole of the female reproductive tissue

stigma

sticky secretion designed to catch pollen

style

what pollen tubes grow through

ovary

holds ovules/megasporangia

ovules/megasporangia

has individual haploid/gametophyte encased

stamen

surrounds carpels

filament

connects the anther to the rest of the flower and elevates the flower so the pollinator can bump into it