8-10: Angiosperms

Question 1

What is significant about Amborella in terms of angiosperm evolution?

Answer 1

It is a basal angiosperm, and provides evidence for a genome duplication event early in angiosperm evolution

Question 2

What 3 defining characteristics do angiosperms have?

Answer 2

Flowers, ovaries encasing the seed, and endosperms

Question 3

What was “Darwin’s Abominable Mystery?”

Answer 3

When angiosperms first appeared in the fossil record, they already appeared to have high diversity and no precursors (however, new intermediate fossils have now been found)

Question 4

What is the function of the ovary?

Answer 4

It protects and encases the seed (it is formed from maternal tissue)

Question 5

Were the first flowers bisexual or dioecious?

Answer 5

Despite amborella being dioecious, it is believed the first flowers were bisexual, and only in certain groups did separate male and female plants evolve.

Question 6

Define fruit

Answer 6

An edible structure which is attractive to animals and gets them to carry seeds

Question 7

What evolutionary feature have herbaceous angiosperms lost?

Answer 7

Secondary thickening

Question 8

What are 2 pros and 2 cons of being woody?

Answer 8

Pros - grow tall (compete for light); resilient
Cons - resource-expensive; inflexible

Question 9

What is the main issue faced by plants in the forest floor habitat (and how does this affect the species that succeed here)?

Answer 9

Low light as not much light penetrates the canopy; species here have EFFICIENT growth (which is why herbs thrive)

Question 10

What are two categories of plants that “cheat” their way to the canopy?

Answer 10

Epiphytes (attach themselves to trees)
Climbers (attached to ground, but grow up a tree by attaching to the trunk)

Question 11

What are ruderals and what types of habitats do they exploit?

Answer 11

They exploit Disturbed Habitats - they are short-lived and exploit transient gaps in ecosystems (e.g., poppies)

Question 12

What are ephemerals?

Answer 12

They grow following rain in the desert, and may persist as seeds or underground structures between rainfall

Question 13

What 4 features found in both cacti and euphorbs are examples of convergent evolution?

Answer 13

Thick cuticles to reduce water loss
CAM Photosynthesis
Sharp spines to deter herbivores
Succulent stems

Question 14

What are two examples of the extra pressures faced by aquatic plants?

Answer 14

Lower O2 and CO2 concentrations than in air, and the thick waxy cuticle making gas exchange more difficult

Question 15

What kinds of environments do carnivorous plants usually grow in?

Answer 15

Low-nutrient environments, e.g., where wet soils reduce breakdown of organic matter

Question 16

What key evolutionary trait do monocots have?

Answer 16

Intercalary/basal meristems, making them grazing-tolerant as they can regrow from the base up

Question 17

During what period (name and approx mya) did conditions become more favourable to monocots?

Answer 17

Paleogene period (66-23mya)

Question 18

In what two ways did conditions become more favourable to monocots during the Paleogene period?

Answer 18

Colder, drier climate (partly due to continents shifting)
Lower CO2 concentration due to formation of mountains

Question 19

Besides grazing, what else are grasses tolerant of?

Answer 19

Fire (because they are short and have basal growth)

Question 20

What feature have grasses evolved that has driven the evolution of herbivore teeth?

Answer 20

Phytoliths - silica crystals which gradually wear down teeth

Question 21

CO-EVOLUTION OF GRASSES AND GRAZERS HAS DRIVEN DIVERISTY OF BOTH

Answer 21

this isn’t a question (enjoy the break from active recall), it’s just an important point to remember

Question 22

What feature did a single plant evolve though mutation, that would normally be detrimental in nature but made them favourable for farming?

Answer 22

The Non-Shattering Phenotype (a single base-pair mutation allowed the seeds to remain attached to the plant rather than being dispersed by wind)

Question 23

What two breakthroughs allowed significant increases in Human Population?

Answer 23

The Haber Process and Borlaug’s Green Revolution (mainly invention of semi-dwarf wheat)