Module 13

Question 1

what is a plant?

Answer 1

multicell eukaryotes
have chlorophyll
(everything but red/brown algae, archaea, bac, animals)

Question 2

what did all plants evolve from?

Answer 2

algal ancestor

Question 3

what are gymnosperms?

Answer 3

non -flowering plants (cycads, conifers ginkgo
become prolific in Mesozoic compared to non vascular plants/ vascular seedless plants (which still present today)

Question 4

what are angiosperms/when did they evolve?

Answer 4

flowering seed plants, seed has endosperm (starchy substance for nutrients)
evolved in Mesozoic and fundamentally changed plant communities

Question 5

location plants in early Tri

Answer 5

Pangea mostly dessert, plants only in higher latitudes places with some open source water

forest not common and plant type dominated by smaller herbaceous forms like types of seed fern, maybe few species conifers

Question 6

what plants found late Tri?

Answer 6

gymnosperms: conifers, cycads and ginkgos

• also the now extinct seed ferns

Question 7

what late Tri conifer is a lazarus taxa

Answer 7

Wollemi Pine

Question 8

what where plants like in Jur

The Jurassic is often called the “Age of the ______”

Answer 8

• dominate trees where the conifers, was a taller trees and important food source for sauropods
• sub canopy of another gymnosperm: cycads

The Jurassic is often called the “Age of the Cycads”

Question 9

what where plants like in the Cre?

Answer 9

conifers became dominate gymnosperm (end age of cycads)

• angiosperms evolve Jur but went radical expansion mid Cre and end Cre more divers then conifers
• common angiosperms Magnolias, Sycamore, Maple, Birch and Willow

Question 10

how could dinos have helped spread angiosperms

Answer 10

• gymnosperms cropped take longer to recover while angi spread quickly

Question 11

what is coevolution

ex

Answer 11

changes in at least two species affect each other’s evolution in a reciprocal manner

common garter snake (resist neurotoxin) and the rough-skinned newt (neurotoxin in skin called tetrodotoxin) from North America
newt can kill several adult humans

Question 12

1.Where do the bacteria that produce the deadly toxins live in the Newt?

2.How does the toxin work to subdue the predator?

3.Who wins the battle of the newt and the bullfrog?

Answer 12

1. in pore in skin
2. stops heart
3. newt

*check

Question 13

ex of helpful co evolution

Answer 13

acacia tree provides shelter for the ants/ rich nectar that is produced at the base of the tree’s leaves. The tips of the leaves also sprout small nutritious packets of oils and proteins.

ants will attack any animals that come to browse on the acacia and will remove the seedlings of other species of plants in the area of the acacia.

Question 14

1. What is the ant’s role in their symbiotic relationship with the acacia tree?

2.How do the ants protect the tree from the predatory attempt by the grasshopper?

3.What does the tree do in exchange for protection from the ants?

Answer 14

1. protector
2. attcking
3. food and shelter

*check

Question 15

evidence early Cre insect that was a pollinator

what does this suggest?

Answer 15

found in amber from the Basque region of Spain.

insects called ‘thrips’ (commonly called ‘thunderbugs’) are trapped in the amber. .

suggest that some insects were preadapted to build this sort of relationship with angiosperms.

Question 16

What did the thrips look like in the amber

Answer 16

• 6 female thrips with rings of hairs on the abdomen appear specifically adapted to maximize pollen collection

pollen grains (probably from a ginkgo or cycad) also appear adapted to be carried by the insects

Question 17

how did gymnosperms and pollinators coevolve
(ginko tree)

Answer 17

Ginkgo either male (cones) or female (ovules at the end of stalks)

suggested that the adults were collecting pollen to feed their larvae that lived in the ovules of the female trees

Question 18

• purpose for a flower
• components
• prevent self fertilization?

Answer 18

• reproduction
• male stamens (producing pollen) and the female pistils (containing ovules), surrounded by petals
• male/female mature at diff times

Question 19

purpose of fruit

Answer 19

attract animal to eat/distribute seed

Question 20

angiosperm coevolution

scent

Answer 20

• guidance mechanism which would allow judge how far away a plant was, and just what area of the flower has nectar.
• useful strategy attract pollinators like moths in low light conditions.
• act as a timing mechanism, reaching its maximum potency when the plant is ready to be pollinated.
• thought that scent might have originally evolved from substances that were intended to deter animals but ended up attracting useful pollinators.
• The actual scent of the flowers can also be keyed to particular types of insect.
• Amorphophallus from Indonesia. It is the world’s largest flower. When ready, it emits a powerful smell of rotting flesh to attract the beetles and “flesh flies” it dupes into helping pollinate the species.

Question 21

angiosperm coevolution

colour

Answer 21

• attract a specific pollinator to a specific plant.
• White, blue and purple attractive to insects
• reds and oranges entice birds.
• nectar guides on some flowers lead animals to nectar.
• Some of these guides are only visible in the UV area of the spectrum, (for insects)

Question 22

angiosperm coevolution

nectar

Answer 22

Nectar is a sugary liquid, high in energy produced by the plant in nectaries.

• placed in location that animal gets covered in pollen.
• The position of the nectaries can be keyed to very specific insects.

example is Darwin’s Orchid (Angraecum sesquipedale). nectaries at the end of very long tubes.
Morgan’s sphinx moth (Xanthopan morgani) that had a proboscis to match the length of the nectaries.

Question 23

Friut

Answer 23

• generally used to attract larger animals
• using cues and guides (colour) to let animals know when it is ripe/ when the seeds ready to be distributed.

Question 24

Mimicry

Answer 24

For example, fly orchid, native to Europe.
- resembles a flying insect, releases a scent that mimics the female sex pheromones of certain bees and wasps.
- When attempting to copulate with the flower, the bees and wasps then get dabbed with pollen!

Question 25

first flowers

Answer 25

• first flowers of the Cretaceous probably resembled magnolias.
• only had a pollen reward, pollinators were probably generalist in nature such as beetles, short-tongued wasps and flies.
• By the time we get to the explosion of angiosperms in the Middle Cretaceous, new varieties of flowering plants emerge with new structures such as nectaries and specialized petals designed for a more specialized relationship with insects.
• By the Late Cretaceous flowering plants were very diverse. At this time insects like wasps and flies were also going through radiations with species evolving specific structures to exploit flowers such as the long-tongued bees and flies.

Question 26

do we know precisely how flowers evolve?

Answer 26

no, appeared emerged fully formed in Cre
Darwin wrote letter to Joseph Hooker

Question 27

how to find most primitive angiosperms?

Answer 27

look form most primitive characteristics
use DNA alaysis

Question 28

what is a clade

Answer 28

species with great similarities

Question 29

what was the most primitive tropical angiosperm found?

Answer 29

Amborella (still exist), base angiosperm family tree, only remaining species in family Amborellaceae

Question 30

where to find Amborella?

Answer 30

Island of Grande Terre of New Caledonia in the South Pacific.

• used to be part gondwana bit seperated and preserved a number of ancient lineages of plant

Question 31

characteristic that makes Amborella primative?

Answer 31

It is an evergreen dioecious shrub (produces either male or female flowers but not at the same time).

• This is more of a gymnosperm than an angiosperm characteristic, which hints at its primitive angiosperm status.

Question 32

how does Amborella grow?

Answer 32

2 phases
1: ground hugging root seedling
2: shrub like with deeper root sys

likes tropical settings

Question 33

problem with amborella fossils

Answer 33

-doesn’t fossilize well
- This problem is compounded: tropical setting unlikely place for the preservation of fossils… not impossible, but certainly not optimal.

Answer 34

urprisingly perhaps, support for an aquatic origin also comes from Amborella too, as like water lilies, it has vestigial gas exchange canals, useful in submerged stems and roots. For further support for this environment, we turn to the group of plants that includes water lilies, the Nymphaeales. Members of this group do have an early fossil record going back to the Early Cretaceous and although they don’t occur right at the base of current family tree of flowering plants, they are pretty close.

Answer 35

he aquatic hypothesis is further supported by one of the oldest complete flowering plant fossils thus far discovered, Archaefructus. The fossil was recovered from a rock unit called the Yixian Formation in NE China, which has become famous for its fossils of feathered dinosaurs and primitive birds.

Answer 36

Many of the fossils from the Yixian Formation were preserved when nearby volcanoes covered them in ash. Volcanic ash is a boon to geochronologists as it often contains crystals that can be dated using isotopic dating techniques. Once dated, it was found that Archaefructus dated to 124.6 MA, during the Early Cretaceous. The first sample found had two branches. At the top of the branch are structures that enclose seeds called carpels, a definitive feature of angiosperms, but unlike modern flowers the carpels are spread out along the stem. There were also possible stamens that would contain the pollen below. However, it lacked petals.

Answer 37

What we recognize as modern flowers could have evolved from primitive angiosperms like Archaefructus by a two-step process. Firstly, the stem that holds the carpels could have shrunk until they were concentrated close to the male stamens. Secondly, the leaves would have became modified into petals.

Answer 38

What we recognize as modern flowers could have evolved from primitive angiosperms like Archaefructus by a two-step process. Firstly, the stem that holds the carpels could have shrunk until they were concentrated close to the male stamens. Secondly, the leaves would have became modified into petals.

Answer 39

hough we are still looking for the first fossil flower, ultimately Archaefructus is an example of a very early angiosperm, and as such might still provide insight into just where flowers first evolved. It stood about 20 cm and inhabited the margins of a lake, probably in very damp or even in shallow water conditions, perhaps accounting for its shallow root system. Is this then yet further evidence that flowering plants evolved in an aquatic environment?

Answer 40

The environment of evolution of the first angiosperms is still very much debated. Some have raised concerns regarding the rapid emergence of a terrestrial flowering plant from an aquatic ancestor. For example, we know that angiosperms spread rapidly soon after they evolved (we know this from the fossil pollen they left behind, even though we have not yet found their fossils). The question is, how could plants that evolved in the water evolve quickly enough to cope with gravity on land?

Answer 41

There is no doubt that some flowering plants did evolve in an aquatic environment early in their history, but the question as to whether this was the environment into which flowering plants first appeared is still very much a matter of debate.

Answer 42

n terms of the timing of the evolution of plants, based on molecular evidence and DNA analysis it is thought angiosperms and gymnosperms last shared a common ancestor sometime that is very broadly called “the pre-Cretaceous”. Hopefully new fossil finds will provide us with more insight in to the earliest stages in the evolution of flowers.

Question 43

1.What type of plants would you have found most commonly if you went back into the Jurassic?

2.Where do angiosperms put their seeds?

3.What is the big difference between pollination in angiosperms versus gymnosperms?

4.By the Late Cretaceous angiosperms had begun to take over. Today, what proportion of the worlds terrestrial plants are angiosperms?

Answer 43

1. conifers, cycads, ferns
2. inside enclosure (fruit)
3. angiosperms need help form other animals to reproduce
4. more 80%

Question 44

What type plant are grasses?
how many species of plants are there

Answer 44

angiosperms
~10 000 species

Question 45

what are Phytoliths

Answer 45

Phytoliths are tiny silica structures found in the leaves of certain plants. They help give grass some of its structural support and may also act as a defensive structure, deterring grazing by some animals

• found in dino poop
  -different type, palm different then grass

Question 46

Gondwanatherians, what’s special about there teeth

Answer 46

• Gondwanatherians, that were scurrying around the feet of the dinosaurs, possessed high crowned or “hypsodont teeth”.
• Many of them are thought to be specialized grass eating grazers who possessed teeth like those of modern horses and cows.
• Their teeth are thought by some to have evolved as a response to the gritty phytoliths in grass.

Question 47

what confirmed the presence of Mesozoic grass

Answer 47

• fossil grass in amber dated 97-100 ma (early-mid Cre)