angiosperms

what were angiosperms 3 key innovations

1. more efficient xylem

2. flowers

3. fruits

describe angiosperms evolution of xylem

• cells with modified ends

• complete perforations without primary or secondary wall

• makes conducting way easier

which innovation of angiosperm lead to its adaptive radiation

flowers!

• special mechanisms for pollination

• directly associated with their rapid speciation

• single mutations can lead to large changes in flower morphology

what are the different male/female reproductive organs

female (carpel): stigma, style, ovary (tissue around ovule), ovule

male (stamen): anther, filament

later plants enclose carpels and stamen in sepals and petals

what is outcross pollination

pollen and stigma on different plants

how do plants spread their pollen effectively

• 80% of angiosperms use animal pollinators

• have evolved to coop unrelated species to carry their gametes

• need animals to visit the plant, contact the anther, then the stigma of a compatible plant

what is the main purpose of flowers

• attract good pollinators

• deter non-pollinating visitors

• manipulate visitor behaviour to maximize pollen transfer

• traits that affect pollination:

  • shape

  • colour

  • scent

  • markings (uv markings animals can see)

  • position

what are fruits

• after fertilization, ovary tissue ripens and becomes the fruit

• that tissue has diversified into different forms and functions

• functions: protect developed seed, seed dispersal

how do fruits disperse seeds?

• not all fruits are meant to be eaten

  • dandelions - wind

  • burs - fur

• some animals eat fruit, seeds pass through gut and gets pooped out somewhere else

• testament to modularity of plants

humans and flowers

• eat them: grains, spices, vegetables

• radiation of angiosperms responsible for culture and cuisine

• global trade and auctions

what are the two big groups that angiosperms are divided into

monocotyledons (monocots)

dicotyledons (dicots)

what are the differences between monocots and dicots

monocots:

• 1 cotyledon

• parallel veins in leaf

• flower petals in multiples of 3

dicots:

• 2 cotyledons

• branching veins in leaves

• flower petals in multiples of 4 or 5