BIOL 324 Midterm L1-5

Name the 4 whorls of a flower from outward to inward

• 1st whorl: Sepals (collectively = calyx) (outermost)

• 2nd whorl: Petals (collectively = corolla)

• 3rd whorl: Stamens

• 4th whorl: Pistil (innermost)

corolla + calyx = ?

perianth

corolla = petals collectively

calyx = sepals collectively

anther + filament = ?

stamen

What is taxonomy?

• Trying to organize organismal chaos (aka evolution)

• It is people who observe, document, and publish what they have observed and tested

• It is how we sort everything in our lives and the thought process to decide what goes with what

What would happen without taxonomy and taxonomists?

There would be no biodiversity

Types of taxonomy

Grouping

“Biology bit” taxa are grouped traditionally by morphology and more recently by evolutionary descent (i.e. “Clades”) reconstructed using phylogenetics

Ranking

Plants organized into different taxa (e.g. species, genera, families, orders)

• Taxon

• Rank

Naming

Naming new taxa and ensuring integrity of nomenclature by applying the ICBN

Taxon

a taxonomic group of any rank/level

Rank

Arbitrarily decided levels of taxonomic organization

Rank free nomenclature proposed (“phylocode”)

Examples of ranking

species, genera, families, orders

Example of grouping

• Traditionally grouped by morphology

• Recently by CLADES (by evolutionary descent)

What is applied when naming new taxa and why?

The International Code of Botanical Nomenclature (ICBN)

To provide meaningful and accurate names

What does grouping, ranking, and naming result in? Explain what each are.

• Checklist - usually the beginning, building a list of what we see in the area being documents

• Flora - a book of the plant diversity for a particular region (describes interactions)

• Key - a dichotomous key of the flora (e.g. does it have hairs, red flowers, etc.)

What is grouping, ranking, and naming based on in taxonomy?

Based on diverse evidence of similarities and differences found in a plant’s morphology, ecology, biosystematics, and phylogenetic relationships

Why is taxonomy important in your life?

• Biodiversity - Would be no way to understand biodiversity fully without it

• Bio-compounds - Many plant groups have similar chemicals and properties that save or kill us

• Economy - we eat 100 million bananas a year and trades at 25 billion/year

• We wouldn’t know what we are eating without all these names (e.g. If you ask for a banana, they are not all the same around the world!)

Why is taxonomy important for science? (5)

• Species discovery

  • what types of organism and how many, share the planet with us

• Identification

  • basis of ecology, conservation, weed science, medicine, all types of organismal biology

• Defines the units

  • for reporting on taxa and their populations (i.e. COSWIC reports)

• Accurate grouping

  • provides powerful tool for hypothesis testing in comparative bio (i.e. within a phylogeny, can we predict a plant’s phenological response to global climate change?)

• Informatics

  • provides “stable names” for ordering and retrieval of biological data (i.e. mapping)

Map / order of how to do taxonomy

1. Herbarium (all taxonomy starts here; basic classification, naming and data storage)

2. Field (plants must be examined in populations)

3. Laboratory (test hypotheses in lab)

4. Repeat (back to the herbarium)

Can genetics replace the science of taxonomy?

No; DNA alone cannot tell us the way an organism looks, behaves, or interacts with the environment without using taxonomy!!

what is the problem with grouping based on fruit colour instead of by morphology, ecology, shared chemistry, and evolutionary descent?

Many dark red fruits have antioxidants but that’s because they turn red since birds like red, so they’ll be more attractive for the birds to take the seeds - not really to do with the fruit itself

If you are a scientists and see 2 plants in an herbarium, how will use the steps / map of taxonomy to identify and determine if they are unique species?

1. I would begin in the herbarium where I would start with basic classification, naming, and data storage of the 2 plants —> this would also remove bias of pre-identification without knowing the name beforehand

2. I would then go to the field and observe the 2 plant species in populations and collect data

3. I would then go to the lab and test my hypotheses if they are unique species

4. After, I would repeat and go back to the herbarium

Structure where seeds are housed in a flower

Ovary

Unique feature(s) of tracheophytes

Have trachea (vascular tissue) which fights gravity

Unique feature(s) of embryophytes

retention of embryo

Seed plant diversity (distinguish the difference between the groups)

• Gymnosperms - naked seeds

• Angiosperms - enclosed seeds, have flowers, double fertilization

Gymnosperms

• Morphologically diverse

• Naked seeds (e.g. cones) —> seeds are NOT enclosed in pistils

• Reproductive structures are found in cones

  • Cycads, conifers, Gingko, gnetoyphytes

  • only c. 950 species (mostly conifers)

Angiosperms

• Enclosed seed

• differ from gymnosperms in having flowers and double fertilization (c. 300,000 species)

Polytomy

When relationships between groups are unresolved

what was the 1st evolutionary land mark for seed plants? explain what it is and its types

Axillary lateral branching

• arrangement/pattern of stem and branch growth on a plant

• different types

  • unbranched

  • dichotomous

  • lateral

what type of branching?

lateral

what type of branching is this and a disadvantage?

Dichotomous

con: becomes weighted down

what type of branching

unbranched

Main axis of shoot vs. lateral branch

Main axis of shoot - growth at an apical meristem

Lateral branch - growth at a new apical meristem (each lateral branch starts off as an axillary bud)

what is this pic showing

shoot apical meristem

Shoots vs. buds

Shoots

• above ground bits include stem, leaves, buds

Buds

• have the potential to become a branch, leaf, or flower

What type of branching do all seed plants have

Axillary lateral branching

2nd evolutionary land mark of seed plants

Ovule/seed; pollen (gymnosperms have)

Pine pollen cone vs. Pine seed cone

Pine pollen cone

• Pollen from leaf-like structures on main axis

Pine seed cone

• Naked seeds on woody lateral branches on a main axis

Ginkgo biloba (family Ginkgoaceae) characteristics - gymnosperm

• One family, one genus, one species (monotypic species)

• Dioecious (has EITHER male (staminate) or female (ovulate, bearing seed called a peduncle))

• Leaves are bilobed, with dichotomous venation

• Ginkgo is a tree

Cycads (characteristics)

• Have 3 families

• In Cycadaceae, there is one genus (Cycas) and 105 species

• East Africa, Madagascar, SE Asia, Tonga

• Usually dioecious

• Are trees/shrubs

• Often unbranched

Conifers characteristics

Which 2 groups of gymnosperms have mobile sperm?

Ginkgo biloba & Cycads

For monoecious plants, why can’t you just take the one plant?

• Because monoecious means there’s 2 types of reproductive (both male and female) cones on one plant

• If you just take one plant, it will result in inbreeding - they’ll both have similar genetics

mitosis = ? = ?

mitosis = cell division = primary growth

where does cell division occur?

apical meristems connection to primary growth

apical meristems give primary growth as they keep doing mitosis and generating cells

what is this entire image showing and what does the red circle show

Entire: Root apical meristem

Red circle: Where cell division is occurring

what is this entire image showing and what does the red / pink circle show

Entire: Shoot apical meristem (bud)

Pink: If (a) gets damaged, these axillary buds will be activated to continue cell division

Explain secondary growth (=lateral meristem)

• Only “woody” things have lateral meristem

Do all eudicots, gymnosperms, and monocots have secondary growth?

• Eudicots & gymnosperms have mainly secondary growth

• Monocots have LOST this function

Apical bud = ?

Leaf primordial = ?

Axillary bud primordium = ?

Angiosperms evolved how long ago in what period

• 125 - 100 million years ago

• Cretaceous Period

Angiosperms: Flowering plants characteristics (important) (5)

• Closed carpels

  • Seeds enclosed within ovary (fruit)

• Male pollen (gametophyte) highly reduced

  • Only 3 cells (1 pollen tube cell and 2 sperm cells - all specialized)

• Penetrative pollen tube growth

  • Eats away at tissue of style to reach ovules for fertilization

  • If it’s self breeding it can choose to stop to prevent inbreeding

• Double fertilization

  • 1 sperm fertilizes egg cell and the other sperm cell fertilizes the polar nuclei to form nutritive tissue (= endosperm - found in seeds)

• Reproductive structures arranged in flowers

Most flowering plant diversity is in ________

eudicots

Definition of a flower (important)

• Short shoot

  • Bearing specialized appendages (modified leaves) for reproduction

• Fertile appendages (modified leaves)

  • Stamens produce pollen

  • Pistil produce ovules with the female gametophyte and egg inside (seeds = fertilized ovules)

• Sterile appendages (modified leaves)

  • Sepals and petals - are protective or attractive (or sometimes develop after pollination for seed dispersal)

• Axis compressed and determinate

  • Determinate - flower determines its life; once you have a flower, the apical meristem for that branch is terminated and “used up”

seed plants = _________ & ___________

gymnosperms & angiosperms

most “basal” angiosperms are trees/shrubs, but what example is an exception?

Nymphaeales (water lilies) are aquatic herbs, usually with syncarpous carpels (i.e. a compound ovary)

Characteristics of Nymphaeales (water lilies)

Note: Tepals does NOT automatically mean primitive plant

Main groups of flowering plants?

Angiosperms:

• Ambrorellales

• Nymphaeales

• Austrobaileyales

Magnoliids:

• Piperales

• Canellales

• Magnoliales

• Laurales

• Monocots

• Eudicots

Groups of basal angiosperms

• Ambrorellales

• Nymphaeales

• Austrobaileyales

• Piperales

• Canellales

• Magnoliales

• Laurales

Last 4 are Magnoliids

List the 5 primitive flora features (important)

1. Elongated receptacle (where everything i.e. ovary, petals, . .is attached to)

2. Spirally arranged parts (not in whorls)

3. Floral parts numerous, seemingly indefinite

4. Floral parts free, not fused

5. Superior ovaries

what type of floral arrangement is shown

spiral arrangment

Characteristics of Amborellales (4)

Pollination of Nymphaeales (chamber flower pollination)

Characteristics of Austrobaileyales

• Flowers are often solitary, with superior ovary and spirally arranged parts (undifferentiated)

• Perianth is made up of undifferentiated tepals

• Carpels are loosely fused, known as apocarpous

Pollination of Austrobaileyales

3 largest groups of angiosperms in order of largest to smallest?

1. Eudicots

2. Dicots

3. Magnoliids

3 main morphological characters within the group Magnoliids

Grouping based on:

• Trimerous flowers (comes in sets of 3)

• Pollen with one pore

• Mostly branching vein leaves

what type of flowers is this

(avocado flower) - trimerous flowers (comes in sets of 3)

Name the orders within the group Magnoliids and their edible plants

• Piperales - pepper

• Canellales - fragrant trees and shrubs

• Magnoliales - nutmeg, mace, paw paw

• Laurales - bay leaf, cinnamon, avocados

Pollination of Magnoliids: Magnolia - name the type of pollination & describe

also chamber flower pollination, similar to Nymphaeales

Pollination of Magnoliids: Piper - name pollination type and describe

What are the 7 basal angiosperm orders (end w/ “-ales”) in Angiosperms?

• Amborellales

• Nymphaeales

• Austrobaileyales

• Piperales

• Canellales

• Magnoliales

• Laurales

Cotyledon

• = “seed leaves”

• food storage for seedling to germinate

• some cotyledons have the ability to photosynthesize, but are different from “true leaves”

Seeds develop from what? List the 4 elements of a seed.

• Seeds develop from ovules

4 elements:

• Cotyledon

• Endosperm (food to survive until true leaves grow)

• Embryo (plant itself)

• Seed coat (protection)

Common characters in monocots and eudicots?

What’s a synpomorphy

Synapomorphies = characteristic present in an ancestral species and shared exclusively by its evolutionary descendants

Name and describe four synapomorphies characters that define monocots.

(1) Monocot embryo (embryo has 1 cotyledon)

(2) Adventitious (= fibrous) root system

• Seedling root (radicle) stops growing early; adventitious roots take over

(3) Parallel leaf venation

• All the veins end at the same point

• *some monocots evolved back to reticulate venation

(4) Herbaceous (herbs)

• Lost secondary growth

Describe different ways to tell the difference between monocots and eudicots.

Monocots:

• Seedling root (radicle) stops growing early; adventitious roots take over

• Parallel leaf venation

• Lost secondary growth

Eudicots:

• Seedling root (radicle) persists and develops into main root: taproot

• Reticulate leaf venation

• Yes secondary growth(?)

Explain why palm tree isn’t a “tree”

• Lack secondary growth (it is woody but has no wood)

  • Doesn’t have rings (no rings = not wood = no secondary growth)

What are some features of beetle/Chamber Flower and Brush pollination?

Beetle/Chamber Flower Pollination

• Fruity fragrance attracts beetles → beetles crawl around eating pollen and old, fallen stamens (food bodies) → pick up pollen on their bodies and deposit pollen from previously visited flowers while crawling around → some species thermogenic (thermogenesis = the plant rewards the beetles by actively heating them at night)

Brush Pollination

• Insects (e.g. hoverflies & beetles) attracted by pollen reward

• Consume pollen but also transfer some to other flowers and plants

• May also be wind pollinated (more random, unpredictable)

• Basically, insects shake plant with their bodies and get pollen

Characteristics of Amborella trichopoda

What species change our understanding of the evolution of monocots and eudicots? How did it change our understanding?

Explain how floral evolution has increased in synorganization

(1) Differentiation of floral parts (e.g. undifferentiated tepals to calyx and corolla)

(2) Reduction in number or loss of floral parts

(3) Changes in symmetry from radial to bilateral to asymmetrical

(4) Compression of the receptacle and change from spiral arrangements of parts to whorled

(5) Fusion of floral parts (e.g. free to fused)

Primitive vs. Advanced Floral Charactres

Primitive vs. Advanced Organisms

Explain the five evolutionary trends in perianth evolution and with examples: Differentiation

• An undifferentiated perianth of tepals is primitive (e.g. basal angiosperms)

• Morphologically and anatomically differentiated sepals and petals are advanced (e.g. eudicots)

However. . .

• Outer and inner perianth whorl (sepals + petals) may look alike morphologically, like Liliaceae (e.g. monocot)

• Perianth of undifferentiated tepals (primitive character) occurs in some otherwise advanced families, like Cactaceae (e.g. eudicot)

Conclusion:

• Group or family can or cannot have differentiated parts, yet this does not define if the group is primitive or advanced

• You must look at many morphological characters from many species, to help define evolutionary relationships based on morphology

Explain the five evolutionary trends in perianth evolution and with examples: Reduction or loss of perianth parts

• Primitive - indefinite number of separate, free parts

• Advanced - smaller, definite number of parts (evidence for reduction can be seen in vestigial structures)

• Sepals and petals - often reduced to 3 or multiples of 3 in monocots, and to 4 or 5 or multiples of 4 or 5 in dicots

• Parts may be lost altogether; calyx or corolla or both may be absent (e.g. grasses)

Explain the five evolutionary trends in perianth evolution and with examples: Symmetry

Explain the five evolutionary trends in perianth evolution and with examples: Symmetry (continued. . . changes in symmetry - the 2 types)

Zygomorphy (symmetry - 1/5 evolutionary trends in perianth evolution)

Define, common in ______ flowers, zygomorphic corollas occur in _______ taxa, typical pollinators and traits to attract pollinators, examples?

• Zygomorphic & asymmetrical flowers are usually associated with a reduction in the number of floral parts

• Common in sympetalous flowers (petals fused near base)

• Zygomorphic corollas occur in polypetalous taxa (e.g Viola and Fabaceae), but are more characteristic of sympetalous families (e.g. Lamiaceae)

• Changes in symmetry of the corolla is almost always an adaptation for pollination

  • Zygomorphic flowers: usually pollinated by bees (hymenoptera)

    • Flower colours vary (except red) usually with nectar guides or UV patterns to attract bees

    • Usually fragrant, broad floral tube

    • Reward is nectar & pollen

• Bilabiate: Having 2 lips (often sympetalous) → e.g. monkey flower, sage

Explain the five evolutionary trends in perianth evolution and with examples: Compression of receptacle

• Primitive receptacle is usually elongate (e.g. Mangoliaceae)

  • Allows floral parts develop in a spiral arrangement

• Advanced receptacle - changed to a flattened receptacle and whorled parts (floral organs attached at the same level) — almost always correlated with a reduction in number of floral parts

Name a receptacle you eat (and is it fused) and a receptacle that has seeds you can eat

Receptacle you eat: Strawberries

• the “dots” are seeds (ovaries) which are NOT fused

• receptacle (the strawberry) makes them look fused by they’re not (trick Q)

Receptacle with seeds you can eat: Sunflower seeds

Ovule = ?

Ovary = ?

Ovule = seed

Ovary = fruit

Explain the five evolutionary trends in perianth evolution and with examples: Fusion (of floral parts)

• Adenate - fusion of different floral whorls

• Connate - fusion of the same whorl

• Fusion of floral parts → one of the most important evolutionary trends in floral evolution

• Connation (fusion of like parts) - of tepals, sepals, or petals into a tube is especially common, but also found in stamens

  • E.g. Tepals = perianth tube, Corolla = sympetalous, Calyx = synsepalous

• Adnation (fusion of unlike parts) - of stamens to the perianth tube often accompanies fusion of petals (e.g. connate petals with adnate stamens — e.g. epipetalous)

Explain the five evolutionary trends in perianth evolution and with examples: Fusion (of stamens)

• Connation

  • Stamen filaments fuse into a stamina tube (e.g. Hibiscus)

  • Anthers of stamens are connate (fused) but filaments are free (e.g. Asteraceae)

• Adnation or fusion of fusion stamens and petals = epipetalous

Explain the five evolutionary trends in perianth evolution and with examples: Fusion (advanced floral fusion)

Hypanthium:

• Advanced floral structured composed of fused sepal, petal, and stamen filament bases

• Can form tubular, cup, bowl, or saucer-shaped structure, fused to the ovary wall

What floral fusion is shown (left and right)?

Left: Adnate

Right: Connate

What type of fusion is being shown? Describe

Adnation (fusion of unlike parts) - fusion of stamens and petals here = epipetalous

what type of fusion shown here? how do you know

Connation - anthers of stamens are connate (fused) but filaments are free

Asteraceae