Plants 5 - Angiosperms

new advangtages of pollen and seeds

more varied dispersal (pollen) & better and cooler dispersal (seeds)

adaptive raditation

when one lineage produces large number of descendent species adapted to many habitats/ecological niches *angiosperm are prime example

Cretaceous Terrestrial Revolution

• 145-80 mya

• angiosperm go from ~0 → 75% of worlds flora

• life becomes more diverse on land than the oceans?

3 Adaptations That were key to Angiosperm Revolution

1. more efficient xylem - vessel element with complete perferation and increases conducting system efficiency

2. flowers

3. fruit

these adaptation allow transport of seeds and pollen efficiently

**but note that gymnosperms had many of these traits too (or similar/developing)

adaptation trait most associated with speciation

flowers - allow for reproductive isolating bc they are directly involved in mate choice and mating…can reduce probability that lineages can mate

Flower Structure

Female Parts (Carpel) made of stigma, style, and ovary containing ovule

Male Parts (Stamen) made of anther containing pollen grains, filament

4 structures of flower that becomes extremely diversified

carpel, stamen, sepals (leafy structures at bottom of flower), and petals

Pollination Definition

the transfer of pollen from the male part (anther) of a flower to the female part (stigma)

Outcross Pollination

*the goal - involves the pollen and stigma on different plants

adaptive signifigance of floral traits

• can attract good pollinators and deter bad ones or non pollinators

• can manipulate visitor behaviour to maximize pollen transfer (bending, shape, size)

what traits can affect pollination

all of them! colour, scent, shape, UV markings, positition of flower

pollination and speciation

pollination is def involved in speciation by causing reproductive isolation in 2 ways

• pollinator shifts - due to simple changes…colour, nectar spur length, flowering length

• mutation of floral trait…proven with white/pink flowers and moth/bee pollination

begining of adaptive radiation

no thing kickstarted (neither flower/pollination)

• gymnosperms had pollinators to

• decline in diversity and plant/pollinator relations

• boring flowers for a while

Fruit structure and function

*key innovation

• ovules develop into having an additional ovary tissue

• this tissue adapts into many things (milkweed fluff, burrs)

• these protect developing seed and help with seed dispersal

• *sometimes meant to be eaten and pooped out

Cotelydons

structures of plants when they first sprout and don’t have leaves…store nutrience for embryos

Monocot vs Dicot Features

Monocot:

• 1 cotelydon

• parallel viens

• multiples of 3 petals

Dicots

• 2 cotelydon

• branched viens

• multiples of 4/5 petals

*actually easier to distiguish viens rather than cotelydon #s

Humans and Angiosperms

• allowed for radiation of human cuisine

• huge markets of flowers historically and now

monocoat lineages

grasses, bananas, irises, trilliums, orchids, lillies

*monocots evolved from dicots kind of

pollinator shift

when a plant species adapts to be pollinated by a different type of pollinator, leading to changes in floral traits and can eventually drive the evolution of new species

difference between gymnosperms and angiosperms

angiosperms enclose ovule in ovary…fruit develops from ovary tissue (ripening)

angios only group to have fruit and flowers

signifigance of plant modularity

• so many copies of redudant limbs and organs and room for failure compared to humans…with one mutation of a limb…humans at a large disadvantage…mutation more likely to be harmful

• with plants mutations are more likely to be neutral/benficial because of this modularity…generally more flexible than animal body plans