Units 1 and 2

Angiosperm

Coined by Paul Hermann in 1690, with flower; having fruits: seeds in a vessel (carpel)

First flowering plants

Split from gymnosperms 250~300 mya

Two main groups of angiosperms

Monocotyledons and eudicotyledons (more species )

Flower

Modified shoot with highly specialized leaves

Sepal

Modified leaf that form the outer layer of a flower bud

Petal

a sterile floral part that usually functions as a visually conspicuous element of a flower

Anther

The part of the stamen that produces and contains pollen

Filament

The stalk that supports the pollen bearing anther in the male reproductive organ (stamen) of a flower

Stigma

Part of the female reproductive system of a flower it is the sticky or waxy part in the center that collects pollen

Style

The slender stalk like structure that connects the sticky stigma to the ovary

Ovary

Female reproductive part of flower located at base of the pistil. Contains ovules. The blank itself will mature into a fruit.

Ovule

The small egg producing structure located within the ovary which are precursor of seeds

Receptacle

The part of a flower stalk where the parts of the flower are attached

Carpel

The innermost part of a flower. The female reproductive organ that produces ovules and facilitates fertilization.

Pistil

Consists of the stigma, style, and the ovary

Stamen

Consists of the filament and anther

Eudicot flower part

4 or 5

Monocot flower part

3s

Eudicot cotyledons

2

Monocot cotyledon

1

Eudicot major leaf vines veins

Netlike

Monocot major leaf veins

Parallel

Eudicot pollen

3 pores (furrows)

Monocot pollen

1 pore

Eudicot primary vascular bundles in stem

In a ring

Monocot primary vascular bundles in stem

Complex arrangement

Pollen production in angiosperm

Meiosis I and II to produce 4 microspores

Mitosis to produce two sperm cells and vegetative cell

Sperm cells are within the vegetative cell

Vegetative cell → pollen tube, sperm cell travel inside pollen tube

Ovule production for angiosperm’s

7 cells (with 8 nuclei) in the embryo sac, 3 on each end and one central cell in the middle

One central cell with 2 polar nuclei

One egg cell located on one end of the sac

Pollen tube growth

Reach the stigmatic surface

Absorb water/ liquid

Germinate and grow through transmitting tissue

Grow towards the ovules

Double fertilization

One sperm cell fuses with the egg cell to form a zygote (embryo)

The other sperm cell fuses with the central cell to form endosperm

Corn

Endosperm (3n)

Embryo (2n)

Ovaries develop into

Fruits

Ovules develop into

Seeds

MRCA

Most Recent Common Ancestor

Clade

Monophyletic group

Sister Group

A monophyletic group more closely related to the group in question than any other

Outgroup

Help to root the tree

Character state

Form or variation of a characteristic (petal color, leaf pubescence)

Ancestral character

Character state of the MRCA

Derived character

Character state that arose in a descendent lineage

Parsimony

Assuming the simplest is true (the fewest possible character state transitions is most likely)

when you hear ancestral trait it is often referring to

The ancestral “character state” of the trait

Just because a species contains the ancestral form of a trait….

Does not make it an “ancestral” species

Every species contains some ancestral and

Some derived character states for different traits

The sisters species of a group does NOT

Contain the ancestral form of all traits

Amborella trichopoda

Margin of the carpels not fused but closed by secretions

Carpels not fused

Spiral arrangement

Only found in New Caledonia

Nymphaea

Spirally arranged tepals

Numerous laminar stamens

Carpels: numerous and fused

Austrobaileyales

Spirally arranged tepals

Laminar stamens/ thick filaments

Carpels unfused to each other

Large variation in carpel

Since Amborella is the most basal group in angiosperm, the MRCA of angiosperms must have flowers that looked just like Amborella flowers

False

Ancestral flowers evolutionary trends

Spiral placement of petals, sepals etc

Many parts

Free parts (petals and anthers)

Hypogynous or superior ovary

Radical symmetry (actinomorphic)

Derived flower evolutionary trends

Whorl placement of parts

Fewer reduced number of parts

Fused parts

Epigynous or inferior ovary

Bilateral symmetry (zygomorphic)