BIOL111 Post Midterm Vocab

virdiplantae

clade of mostly autotrophic eukaryotes that includes all green algae and land plants

experimental evolution

method used by Dr. Graham Bell to do measure Carbon uptake. studies evolutionary changes in living populations as they adapt to controlled environments. conclusion of the study was that plants carbon mechanism degenerates over time when it’s not being used. Eg. in a high-C enviro, it’s not necessary to have more efficient carbon uptake. no natural selection.

non-vascular plants

plants without vascular tissue (containing xylem and phloem). earliest branching group.

bryophytes

group of small, non-vascular land plants that include mosses, liverworts, and hornworts. no true roots, stems, or leaves.

flavonoids

plant-based compounds that give fruits, vegetables, flowers, and teas their vibrant colors and flavors. they act as natural antioxidants and help protect plants from UV radiation, pests, and environmental stress.

cuticle

watertight sealant covering land plants. they do not allow gas exchange, so they evolved with the stomata.

sporopollenin

the encasing around a pollen grain. so tough that you can find 1000 year old pollen grains that retain their shape.

gametangia

specialized reproductive organs in early plants that protected gametes from physical drying and damage.

liverworts

one of the bryophytes. the free living gametophyte of a fern looks like one.

hornworts

group of non vascular land plants. the common name refers to the elongated horn-like structure, which is the sporophyte. they have stomata on their sporophyte.

vascular tisse

contains xylem and phloem. distinguishes nonvasc from vasc plants. we know it evolved only once because vascular plants are monophyletic.

extant

existing species today

Silurian

most morphological innovations occurred during this time period. in the mid silurian, plants were able to branch, leading to roots and stems.

Prototaxites

extinct genus of large macroscopic eukaryote dating from the Late Silurian until the Late Devonian periods. they dwarfed early land plants.

Stoma/Stomata

key innovation for drier environments. it is an opening/pore surrounded by special guard cells. plants change the opening and closing of the stomata depending on their environment.

Tracheid

elongated hollow dead cell in the xylem of vascular plants that transports water and dissolved minerals while providing structural support. they make up xylem.

Xylem

specialized vascular tissue in plants. transports water and dissolved minerals upward from the roots to the stems and leaves, while also providing structural support. composed of tracheids.

Lignin

one of the most abundant polymers on earth after cellulose. they are approx 25% of land-based biomass.fungi are one of the first efficient decomposers of lignin. lignin also thickens conducting cells in vascular tissue.

Gilboa trees

trees in the world’s first forests (late Devonian). no leaves, just increasingly fine branches. also no wood.

sporophyte dominant lifecycle

the life cycle of vascular seedless plants. the sporophyte is much larger and longer than the gametophyte. the advantage of sporophytes is that they respond to varying environments more efficiently

sporangia

on the fertile leaves of ferns, spores are produced in the sporangia, clustered into sori.

sori

a visible cluster of sporangia.

club moss

true vascular system. tree-like club mosses were a major component of Carboniferous forests, in addition to tree ferns and giant horsetails.

fern

first fossils found in late Devonian. roots very similar to seed plants. produces both fertile and sterile leaves. the fern you see is the sporophyte. the gametophyte is free living and looks a bit like liverwort.

evolutionary stasis

biological phenomenon where a species or lineage shows little to no net morphological change over vast stretches of geological time.

epiphyte

a plant that grows on the surface of another plant. 25-30% of ferns are epiphytes, mostly tropical.

vascular cambium

ring of dividing cells beneath the bark of a tree. they divide in two directions. Inner side of the circle, produces xylem tissue (lignified) and on the outside it produces phloem tissue. In xylem, water/nutrients go up, phloem sugars flow down.

phloem

tissue in plants that transports organic compounds, (primarily sugar), made during photosynthesis from leaves to the rest of the plant.

Carboniferous

period after the Devonian. ancient fern forests dominated vast wetlands of Pangea.

heterospory

the quality of having 2 types of spores of different sizes. the first true trees arachaeopteris had heterospory. pollination is only made possible by heterospory. seeds are also made possible by heterospory.

megaspores & microspores

the two sizes of spores in heterospory. megaspores →megagametophytes. microspores →microgametophytes. led to the evolution of seeds and pollen. megagametophytes are key components of a seed. pollen is a microgametophyte.

integument

protective surrounding around a microsporangium. integument is part of all modern seeds, and develops into a seed coat.

ovule

a megasporangium enclosed in integument. it is dessication resistant, meaning seeds can last in drier environments.

pollen tube

slender, tubular structure produced by the male gametophyte (pollen grain) of seed plants when it germinates upon contacting a compatible female stigma. sperm cells swim/travel down the pollen tube to reach the ovule.

angiosperm

flowering plants that produce seeds enclosed within an ovary. fruits and flowers were the innovations of angiosperms. one of the greatest adaptive radiations in the history of life. during the cretaceous period they exploded with diversity.

adaptive radiation

when one lineage produces an unusually large number of descendant species adapted to many habitats.

cretaceous terrestrial revolution

• during this period many lineages including angiosperms explode with diversity. For the first time, life on land is more diverse than in the oceans.

reproductive isolation

the last and hardest step of speciation. flowers were directly involved in mating and mate choice. simple changes in flowers led to pollinator shifts, which can be the 1st step to reproductive isolation.

carpel

female reproductive organs in a flower. enclosed by both sepals and petals. located at the very center of the flower.

stamen

male reproductive organs in a flower. enclosed by both sepals and petals.

ovule

ovules develop in the ovary. Everything is fully enclosed. No contact between megasporangium and the outer environment. The stigma is where pollen is deposited. 

ovary

where ovules develop. fully enclosed.

anther

where the male pollen grains develop.

sepals & petals

surround the carpel and stamen of a flower. the sepal is the outermost layer that protects the flower while it is still a bud.

pollinator shift

can be first step in reproductive isolation. Simple changes in flowers (eg colour, nectar spur length, flowering time) can lead to pollinator shifts. Floral traits can: attract good pollinators, deter non-pollinating visitors, manipulate visitor behaviour to maximize pollen transfer. Almost any floral trait can affect pollination, including: colour, scent, position, markings

pericarp

ovary wall, where most seed dispersal structures develop from. it is the ripened and modified wall of a plant ovary that surrounds and protects the seed inside a fruit.

cotelydons

how monocots and dicots are distinguished from each other. a cotyledon is the embryonic “seed lead” inside a plant’s seed that emerges when the seed germinates. they nourish the seed, but die soon after.

monocots

angiosperms with one cotyledon in their embryo. they have parallel veins. flower petals are multiples of 3. most of human diet is monocots, such as all grains.

dicots

angiosperms with two cotyledons in their embryo. they have branching veins. flower petals are multiples of 4 or 5.