Lecture 1

Question 1

What is systematics?

Answer 1

A science that proposes hypothesized ancestor-descendant relationships between organisms and classifies organisms into named groups based on relatedness

Uses both genetic and morphological/physiological evidence

Question 2

What is the use of systematics to science and society?

Answer 2

Quantifying diversity: gives organisms names

Understand how groups are related: creates an ordered, hierarchical system, with different levels of classifications

Question 3

List the classification hierarchy from largest group to most specific

Answer 3

Domain, kingdom, phylum, class, order, family, genus, species

Question 4

Phylogeny

Answer 4

Hypothesized ancestor/descendent relationship, or evolutionary history, of a group of organisms

Question 5

What is a clade?

Answer 5

A group of organisms made up of an ancestor and all of its descendants

Question 6

What is a synapomorphy?

Answer 6

A trait and characteristic that is shared by members of a clade, implying that is was present in a common ancestor

Question 7

What is homoplasy?

Answer 7

When the same trait arises in different lineages due to evolutionary pressure

Homoplacious traits (traits that are similar, but independently derived) can cause confusion in classifications

Question 8

Describe monophyletic

Answer 8

A group that includes ALL of the descendants of a common ancestor–this group would satisfy the criteria to be a clade

Question 9

Describe non-monophyletic

Answer 9

All other kinds of groups, these do not satisfy the criteria to be a clade.

They can be:
- Paraphyletic groups: a group that has all group members sharing a common ancestor, but does not include a small number of groups that are also descendants (e.g. dinosaurs do not include birds)
- Polyphyletic: a group that is made up of not-closely related smaller groups (i.e. not having a shared common ancestor) that have been erroneously grouped on the basis of homoplasious characters

Question 10

What are algae/seaweeds?

Answer 10

Heterogenous group of aquatic photosynthetic organisms (that are not closely related to each other)

Many are multicellular, but do not share a multicellular ancestor

Question 11

What are stramenopiles

Answer 11

Brown algae (includes multicellular keps)

Diatoms: unicellular, non-motile

Microalgae (plankton): either unicellular or in string

Question 12

What are rhodophytes?

Answer 12

Red algae (includes multicellular nori)
Coral symbionts (unicellular)

Question 13

What are viridiophytes?

Answer 13

Green plants/chloroplastida

Includes green algae and land plants
Monophyletic group
>300,00 described species

Traits that make them similar to each other and different from other groups (synapomorphies) are mainly chemical in nature

Question 14

What are embryophytes and what are its the synapomorphies?

Answer 14

Land plants
- plants had to adapt to succeed out of water (the traits below are thought to have helped with this)

Traits:
- Embryo stage early in the life of the sporophyte (the sporophyte is the 2N life stage of plants)
- Multicellular sporophyte
- Multicellular reproductive structures
- A cuticle

Question 15

What are the three types of bryophytes?

Answer 15

Mosses (quite diverse)
Liverworts (somewhat diverse)
Hornworts (not very diverse)

Question 16

What are tracheophytes?

Answer 16

Vascular plants (spermatophyte dominant, vascular tissue more specialized)
- lycopods and similar
- ferns and relatives
- gymnosperms evolved seeds
- angiosperms evolved flowers and fruits

Question 17

Describe mosses

Answer 17

Most diverse group of bryophytes
Upright, leafy gametophyte is dominant phase
Multicellular rhizoids
Stomates
No true roots
Can go dormant for a long time and can hold a lot of water

Question 18

Describe the fertilization process of mosses

Answer 18

Gametophytes (haploid generation) are the main moss that we observe
- after an egg cell is fertilized by a male moss gametophyte sperm, the sporophyte (diploid) generation grows out of the top of female gametophytes (top right)

Capsule containing haploid spores breaks open (bottom right) and these go through a protonemal stage (like green algae filament), and then grow up into haploid male or female gametophytes

Question 19

Describe liverworts

Answer 19

Approx. 9000 species, thalloid or leafy growth possible
Lack stomates
Gametophyte is the dominant phase
Same (or similar) reproductive cycle as mosses

Question 20

Describe hornworts

Answer 20

Approx. 100 species
On chloroplast per cell
Meristematic growth of sporophyte similar to vascular plants

Question 21

Describe main characteristics of tracheophytes (vascular plants)

Answer 21

Vascular tissue, xylem with tracheids (elongated cells, thickened cell wall, dead when functional)

Pits connect tracheids

Gametophyte dramatically reduced

Sporophyte very elaborate, branched

Question 22

What are the three important groups of vascular plants?

Answer 22

Monilophytes: the seedless vascular plants which includes ferns and horsetails

Lycophytes: other spore-producing groups (such as clubmosses) with many extinct groups

Spermatophytes: seed plants, which includes the gymnosperms and angiosperms

Question 23

What are some characteristics of early tracheophytes?

Answer 23

Multi-branced sporophyte
Tracheids
Reproduction via spores

Still no leaves or roots

Question 24

Lycopodaceae

Answer 24

Spirally arranged microphyll (leaves with single veins)

Large sporangia with numerous spores, in leaf axils or in simple strobili

Question 25

What are quillworts (isoetes)

Answer 25

Aquatic plants common in lake edges–spores are at the bottom of leaves

Genus of lycopods

Question 26

Equisetaceae

Answer 26

Horsetail family

Early diverging, distinct morphology

Very reduced whorled leaves, whorled branches (in some)

Photosynthetic stems

Silicon is an essential nutrient

Large sporangia with numerous spores, in terminal compounds strobilus

Question 27

Where are equisetum found?

Answer 27

Only 15 species globally –> most common and diverse in northern North America. Not native and problem species in Australia, New Zealand

Question 28

What are features to identify a species in the equisetaceae family?

Answer 28

Stem cross section

Leaf/branch traits

Height

Question 29

What are leptosporangiate ferns and what are some characteristics?

Answer 29

One of the four subclasses of ferns

Traits:
- circinate vernation
- photosynthetic gametophyte
- sporangia with stalk, in sori on abaxial leaf surface, or on special sections or on separate fertile leaves
- sporangia with annulus (a partial ring of cells with different thicknesses, which result in a popping open and release of spores under dry conditions-always a multiple of 32 spores/sporangia: usually 64)
- life cycle includes a gametophyte stage (1N) which is independent from the sporophyte stage (2N)

Question 30

Osmundaceae traits

Answer 30

Royal Fern family

Sporangia with 256 spores and patch annulus on separate fronds or pinnae NOT associated with leaf tissue

Question 31

What family is the Osmundastrum cinnamomeum part of?

Answer 31

Osmundaceae

Question 32

What family is the Osmunda regalis part of?

Answer 32

Osmundaceae