BIOS21A Exam 2

benefits of life underwater

benefits of life underwater

1. sperm can swim to egg

2. supports body shape

3. easy access to water

negatives to life underwater

1. limited co2

2. less sunlight

benefits to life on land

1. more sunlight

2. more co2

3. escape oceanic primary consumers

negatives of life on land

1. drier

2. sperm can't swim unless close to water

3. no support from water for structure

3 parts of a plant

• roots: obtain water, minerals, nutrients

• leaf: photosynthesis

• stem: structure + transport

adaptations of alternation of generations in plants

• maternal contribution: female gametophyte gives nutrients and protection to the next sporophyte stage

• gametangia: sex organs that produce and protect gametes

• sporopollenin: resist infection and degradation of spores

apical meristems

• shoot apical meristem: grows up to light

• root apical meristem: grows down to water and minerals/nutrients

structural adaptations of plants (cellular)

• cellulose cell walls: cells are stronger in shape

• central vacuole: draws water into the cell making it stronger

vascular tissues (what are the 2 types)

• xylem: transports waters in tissues from roots to shoots

• phloem: transports sugars

waxy cuticle

• secretion outside of the plant organs of lipids

• prevents water loss

secondary metabolites

• defends against defenders

• toxins, bitter compounds, spicy compounds

meristems (what is it? what are the 4 meristems)

• sources of new cells (through mitosis, generic/undifferentiated cells)

• shoot apical meristem: grows up

• root apical meristem: grows down

• lateral meristem: grows wide

• axillary bud meristem: in emergency will turn into apical meristem

pattern of shoot growth (structure of the plant itself)

• node: point on shoot where a leaf grows

• internode: stem

• petiole: supports leaf

• leaf

shoot apical meristem structure

• leaf primordia: young leaf

• procambium: will turn into vasculature

• protoderm: will turn into dermal tissue

• ground meristem: will make ground tissue

• axillary bud meristems: emergency bud

root apical meristem structure

• root hair

• ground meristem

• procambium

• root apical meristem

• root cap

basic tissues of plants (3 types)

• dermal tissue: outer covering

• vascular tissue: transportation cells

• ground tissue: photosynthesis, storage of water/sugar

dermal tissue structure

• stoma: hole

• epidermis: lets light pass, protects tissues from water loss and pathogens

• trichome hair cells: filters excess sun

• guard cells: allows co2 to go in and o2 to go out

ground tissues (3 types)

• parenchyma

• collenchyma

• sclerenchyma

parenchyma

• thin primary cell wall

• storage of sugars and starch

• does photosynthesis

• found in leaves, roots, the cortex, the pith, and stems

collenchyma

• thickened primary cell wall (more cellulose)

• supports epidermis (near vasculature)

• in celery

sclerenchyma

• thick secondary cell wall with lignen (hardening molecule)

• red

• strong support cells

• mature when dead

• found in pear, stone cells, vascular bundles

xylem and its cell types

vessel elements: dead when working tracheids: long fiber

phloem and its cell types

• phloem: alive, pump sugar and protein

• sieve tube elements: pumping

• companion cells: supports the sieve tube elements by providing metabolic needs (proteins, ions, nutrients)

plant life spans (3 types)

• annuals: live for one year, soft/herbacious

• biennial: 2 years

• perrenial: many years, thick and woody

primary growth

• shoot apical meristem & root apical meristem: increase in height and depth of all plants

secondary growth (what are the 2 types)

• lateral meristems: increase width using

1. vascular cambium - makes outer secondary phloem and inner secondary xylem

2. cork cambium - makes cork cells (bark) and phloem

annual growth rings

• are made of xylem and kept each year

• counting the rings shows how many years a tree has been alive

monocots

• embryo in seed has one cotyledon (embryonic leaf)

• parallel veins

• fibrous roots

• flower organs in multiples of 3

• example: corn, grass

dicots

• embryo in seed has 2 cotyledons

• branched veins

• tap root

• flower organs in multiples of 4/5

• example: beans

monocot stem

• vascular bundles are scattered

• epidermis is outside

• ground tissue fills in everywhere

dicot stem

• vascular bundles are circular arranged

• cortex: inside the epidermis before vascular bundles (inside parenchyma)

• pith: central parenchyma

basic structure of roots

• endodermis: secretes the casparian strip

• pericycle: cell layer

• vascular cylinder: Steele

• ground tissue (parenchyma): stores starch

• epidermis

casparian strip

• seal in moisture into the center (vascular cylinder) so liquids are not lost

pericycle

• inside endodermis

• makes lateral roots

• helps increase absorption

• starts the new roots

monocot root layers

• epidermis

• cortex -endodermis with casparian strip

• vascular tissue

• pith

dicot root layers

• epidermis

• ground tissue

• vascular cylinder (NO PITH, solid xylem star w/ patches of phloem)

dicot vascular cylinder

• endodermis

• pericycle

• phloem

• xylem star

general parts of leaves

1. petiole: stem to leaf

2. Midrib: main vein

3. veins

4. Margin: edge of leaf

5. lamina: flat blade

difference between structure of monocot leaves and dicot leaves

monocot:

1. 2 stoma w/ guard cells at the top and bottom

dicot leaves:

1. has pallisade parenchyma (absorbs more light) and spongey parenchyma for gas exchange.

2. 1 stoma w/ guard cell on lower epidermis

adaptations of stems

• rhizome: underground stem that grows sideways (ginger)

• tubers: underground stem that stores starch (potato)

• bulb: underground fleshy leaves that store sugar (onion)

adaptations of roots

aerial roots:

1. help get air

2. can absorb water and store it e.g orchids

prop roots

1. push up the stem for sun e.g. corn

adaptation of leaves

• leaves for clones (fern)

• leaves to catch animals (carnivorous plants)

• spines (cacti)

basal taxa of plant divisions

green algae phylum charophyta

charophyta

• life cycle: alternation of generations

• dominant phase: gametophyte (n)

• shared plant characteristics:

1. gametangia - multicellular sex organs

2. sporopollenin

3. archegonium

4. antheridium

bryophytes "mosses"

1. time of evolution: 450+ mya

2. dominant phase: gametophyte (n)

3. basic adaptations: sporopollenin, cellulose cell walls, gametangia

4. habitat: wet/moist freshwater habitats (sperm still flagellated)

bryophytes phyla

1. marchantiophyta (liverwort)

2. anthcerophyta (hornwort)

3. bryophyta (true mosses)

phylum marchantiophyta "liverwort"

1. body form: lobed thallus (no leaf)

2. reproduction

   • asexual: mitosis

   • gemma in gemma cups pop off when hit with water to asexually reproduce

   • sexual reproduction: archegonia makes egg and antheridium makes sperm

     • female gametophyte w/ archegonia looks like palm tree

     • male gametophyte w/ antheridia looks like clover

phylum anthocerophyta "hornwort"

1. body form: flat thallus, horn shaped sporangium

2. sexual reproduction

phylum bryophyta "true mosses"

1. body form: no true leaves, vasculature, roots, or stems

2. reproduction: sexual reproduction -> gametophytes make gametes

bryophyta sexual reproduction

• capsule: sporangium (makes spores using meiosis)

• spores grow into protorema (1st cell of gametophyte)

pterophytes "ferns" (phylum monilophyta)

seedless vascular plants

1. time of evolution: 420+ MYA

2. dominant phase: sporophyte (2n) -- very large

3. basic adaptations: vascular tissue (xylem, phloem), roots, stems, leaves

4. still use flagellated sperm, but can live in drier places

phylum monilaphyta classes

1. equisitopsida (horsetails)

2. psilotopsida (whisk ferns)

3. polypodiopsida (true ferns)

phlylum monilophyta class equisetopsida

• main stem has very reduced leaves (mainly photosynthesis in stems)

• found in swams

phylum monilophyta class psilotopsida

• the stems branch with sporangium at the top

phylum monilophyta class polypodiopsida

• can get very big (e.g tree ferns)

• has deep roots and stems

• fronds: big leaf shape made of small leaves called leaflets

fern sporophyte structure

• has sorus: circle of sporangia that makes spores

• protected by epidermis

fern gametophyte to sporophyte

• gametophyte is tiny and heart shaped

• uses sex organs (antheridium -> sperm, archegonium -> eggs)

primary succession

• 1st land was lava which turned into rock

• 1st pioneer plants were bryophytes which weathered the rocks and turned it into soil

ecological roles of non-vascular plants

• animals eat bryophytes

• monilophyta weathers rock to soil

• grow to hold soil

gymnosperms

1. time of evolution: 330 mya

2. dominant phase: sporophyte (2n)

3. basic adaptations:

   • seeds: embryo of the next sporophyte; has nutrients and seed coat protection

   • pollen: particle that transports and delivers sperm without the need for water

gymnosperm phyla

1. coniferophyta

2. cycadophyta

3. ginkgophyta

4. gnetophyta

coniferophyta

1. uses structures called strobilus (structure that holds sporangium) to produce spores

2. xylem only uses tracheids

spore structure

1. homosporous plants a. bryophytes and pterophytes b. single/same type of spores and sporangium

2. heterosporous plants a. gymnosperms + angiosperms b. different/2 types of spores and sporangia

sporophyll

leaf w/ sporangium in a strobilus

male vs female strobilus

1. male strobilus -> pollen cone a. microsporangium: makes microspores through meiosis b. microspores have microscopic microgametophyte tissue in them which make sperm

2. female strobilus -> ovulate cone a. megasporangium: makes megaspores through meisosis b., megaspores have microscopic gametophyte tissue in them which creates the embryo-sac which makes an egg

fertilization of coniferophyta

• pollen has wing cells which help it fly through the air, the pollen creates a pollen tube when it is in the megasporangium and delivers sperm to fertilize the egg

coniferophyta ecology

• homes for animals like birds

• seeds = food

• used as wood/lumber

cycadophyta "cycads"

• look like palm trees with compound leaves

• palm fronds

• usually one main cone

• pollinated by beetles

ginkgophyta "gingko trees"

• fan shaped leaf, branched veins

• pollution toleration

• female gingko seeds smell bad

gnetophyta

• allergy medications

• meth

• 2 long leaves

angiosperms

1. time of evolution: 100+ mya

2. dominant phase: sporophyte

3. basic adaptations: flowers and fruits

4. habitats: along equator

angiosperm phyla anthophyta groups

1. magnollids

2. monocots

3. dicots

benefits of angiosperm adaptations

1. flowers attract pollinators with colors and nectar

2. pollinators transport pollen to other flowers

detailed structure of the flower

1. calyx: circle of sepals (protection of the developing flower)

2. corolla: circle of petals (attraction of pollinators)

3. androecium: circle of stamens (make pollen)

4. gynoecium: circle of carpels (egg)

in androecium...

1. stamen made up of the anther (top part) and filament

2. in the anther, there are microsporangium which make microspores which produce microgametophyte tissue which produces pollen

pollen development

microsporangium -> microspore -> microgametophyte -> pollen

*the pollen grain has a generative cell (generates 2 sperm) and a tube cell (makes pollen tube)

female reproduce organs

1. in the gynoecium

2. carpel consisting of stigma (gets pollen), style (thin path for the pollen tube), and the ovary with ovules (megaspore that will make the megagametophyte which will make the embryo sac)

ovule development

ovule -> megaspore -> megagametophyte -> embryosac

*ovule has 2 polar nuclei and an egg cell

summary of life cycle

1. pollen from anther lands on stigma

2. pollen grows a pollen tube through the style

3. pollen delivers 2 sperm to an ovule inside the embryo sac

fertilization process

1. double fertilization

2. 2 polar nuclei (n) combine with 1 sperm (n) = 3n triploid endosperm (turns into nutrients for the seed)

3. egg cell (n) + sperm cell (n) = zygote (2n)

angiosperm embryos stages

• torpedo stage

• heart stage

• globular stage

structure of the seed and embryo

1. hypocotyl: embryo stem

2. radicle: embryonic root

3. endosperm inside (3n)

4. seed coat outside

5. cotyledon: embryonic leaves

magnoliids

1st 2 whorls (sepals + petals) combined in a tepal

adaptations (and ecology)

• plants evolved with herbivores (e.g spines on a cactus)

• food source

• change looks to attract different pollinators (flap: bee pollinator, mimicry: evolved to look like insects to attract insects)

seed dispersal in seeds

• hair and wings for air

• floating for water

• seeds in animals poops and get stuck to their fur

• explosive seeds (okra)

ecological roles for humans

• food

• medication