Angiosperm evolution

•      Most successful division (currently)

•      Most closely related to gnetophytes

•      235,000 species

–    2 classes (plus a few)

•    Monocots

•    Dicots

•    Paleoherbs

–    >300 families

  Angiosperm evolution

•      Size

–    Duckweeds to eucalypts 300 feet tall

 Angiosperm evolution

•      Habit

–    Erect

–    Vines

–    Epiphytes

–    Annuals and perennials

–    Saprophytic

–    Parasitic

Angiosperm evolution

•      Habitats

–    Aquatic

–    Desert

–    Cold and Hot

–    Rainforests

–    Arctic Tundra

Angiosperm evolution

•      Ancestral angiosperms probably shared a common ancestor most recently with the Gnetophytes

•      Oldest fossils about 130 million years

•      By 90 MY, full diversity

Other noteworthy events

•       First insects 300 MYA

–     Insects already diverse by the time of flowering plants

–     Not driven by coevolution

•       Earliest mammals 225 MYA

–     Mammals already diverse by 100 MYA

•       Earliest birds 150 MYA

–     Birds are leftover dinosaurs

•       Earliest primates 50 MYA

•       Grasses 25 MYA

–     Grazing herbivores coevolved

•       Earliest hominids 15 MYA

•       Earliest biped 4 MYA

•       Earliest Homo sapiens (archaic) 0.5 MYA

•       Modern H. sapiens 35,000 years ago

Monocots and Dicots

•      Supported by DNA sequencing

•      Magnoliids are basal

Monocots and Dicots

•      Monocots

–    Grasses

–    Lilies (the simplest)

–    Palms

–    Irises

–    Cattails

–    Orchids

 Monocots and Dicots

Somatic Advances

•      The usual sort of stuff

–    Extensive xylem in dicots

•    Vessel elements as well as tracheids

–    Fibers

–    Taproots in dicots

•      Broad leaves

–    Advantage?

–    Disadvantage?

Somatic Advances

•      Deciduous

–    Increases the range

•      Rate of reproduction

–    2-50 times faster than gymnos

•      Annuals

–    Lose secondary growth

–    Germinate, mature, reproduce and die in a single season

Somatic Advances

•       Plasticity – lots of organ modifications

•       All sorts of reasons:  Defense

–     Thorns

–     Hairs

–     Toxins

•       Urticaceae

–     Stinging nettles

–     Histamines and acetylcholine

More plasticity

•       Stem modifications – tendrils

•       Stem modifications – storage

•       Root modifications – photosynthesis

•       Root modifications – storage

•       Root modifications – structure

–     Prop roots, buttress roots

•       Leaf and Branch modifications

–     Thorns and spines

•       Leaf modifications

–     storage

Reproductive Advances
Flowers

•      Sterile parts

–    Sepals

–    Petals

•      Fertile parts Stamen (male)

•    Anthers and filament

–    Pistil (female)

•    Stigma

•    Style

•    Ovary

Reproductive Advances
Flowers

•      Flowers are prefertilization adaptations

–    Nurture and protect gametophytes

–    Attract pollinators

•    Color

•    Food

•    Shape

•    Odor

–    Disperse the male gametophyte

–    Make a fruit

•      The fruit is a postfertilization adaptation

–    Nurturing and protection of the seeds

–    Dispersal of the seeds

Flowers
Sterile parts

•      Sepals

–    Usually not colored

–    Protective of the developing flower bud

–    Tepals

•      Petals

–    Highly ornamented in shape and color

•      Nectaries

Flowers

•      Complete – having all four whorls

–    Incomplete – having less than four

•      Perfect – having both sexes

–    Imperfect – having only one sex on the flower

•      An imperfect flower is always incomplete

•      An incomplete flower could still be perfect

 Flowering plants

•      Synoecious (same house)

–    Both sexes on same flower on same plant

–    Flower is always perfect but can be incomplete or complete

 •      Monoecious (one house)

–    The plant has both sexes

–    Flowers are incomplete and imperfect

•    E.g., corn

•      Dioecious (two houses)

–    There are two kinds of plants, male and female

–    Flowers are always incomplete and imperfect

•    E.g., marijuana, hollies

Advanced vs Primitive floral characters

Flowering plants
Inflorescences

•      Flowers can be solitary or in clusters on a single pedicel