Evolution of reproductive strategies in plants

Question 1

What kind of organisms are plants?

Answer 1

Sessile.

Question 2

What environment were plants originally in?

Answer 2

Aquatic areas.

Question 3

What did colonisation of land require?

Answer 3

Considerable adaptations - support, avoiding drying out, obtaining water and gases, reproduction, resisting predation.

Question 4

What were the four key points in evolutionary development?

Answer 4

Land plants, vascular plants, seed plants, flowering plants.

Question 5

What two seres of things happened over time?

Answer 5

Explosions of diversity and catastrophic extinctions.

Question 6

What kind of plants existed initially?

Answer 6

Vascular plants, lycophytes and pteridophytes.

Question 7

What came after vascular plants?

Answer 7

Seed-bearing plants (gymnosperms).

Question 8

What came after seed-bearing plants?

Answer 8

Flowering plants (angiosperms).

Question 9

What is an anthophyte?

Answer 9

Any flowering plant.

Question 10

What is the Anthopyte hypothesis (angiosperm evolution)?

Answer 10

Bennettitalles suggested to be link between Gnetophytes and Angiosperms, based on early molecular data.

Question 11

What did evolution of flowers lead to?

Answer 11

Major evolutionary event leading to massive diversification of species.

Question 12

What is one plant considered to be the oldest angiosperm so far?

Answer 12

Montsechia Vidalii (debated) or Archaefrustus Sinensis.

Question 13

What are the key terms for flowering plants?

Answer 13

Sepal, petals, stamen, carpel, tepal - four whorls.

Question 14

What is the Sepal?

Answer 14

Calyx, outer part of flower (leafy green structures).

Question 15

What are the petals?

Answer 15

Corolla, main bulk, numerous and individual, may be fused.

Question 16

What is the stamen?

Answer 16

Androecium, produces pollen, consists of anther and filament.

Question 17

What is the Carpel?

Answer 17

Gynoecium, female structure, composed of ovary, style and stigma.

Question 18

What is the Tepal?

Answer 18

Flower/ sepal hybrid structure.

Question 19

What is Amborella trichopoda?

Answer 19

Small plant native to rainforest of New Caledonia - South Pacific.

Question 20

What is significance of A.trichopoda?

Answer 20

Related to all flowering plants, oldest confirmed branch of angiosperm family tree.

Question 21

What structural difference did early flowers most likely have?

Answer 21

Tepals rather than sepals and petals.

Question 22

How was the predicted structure of the first flower developed?

Answer 22

Analysis of genetics of flowering groups, extrapolated common features back to identify common likely features.

Question 23

What is the probably structure of first flower?

Answer 23

Tepals and stamens, layered whorls of 3, 11 or more tepals and stamens, male and female structures, ~1cm diameter.

Question 24

Did flowers become more or less complex over time?

Answer 24

Less complex, more aligned to common format.

Question 25

How has the floral structures changed over time?

Answer 25

Simplified, flattened from complex spiral arrangements to simpler symmetrical arrangements.

Question 26

What did later development divide tepals into?

Answer 26

Petals and sepals.

Question 27

When did petal fusion occur?

Answer 27

Later in evolutionary lineages - specialised flowers, specific functions to encourage pollenators.

Question 28

What happened to symmetry of flowers over time?

Answer 28

Radial symmetry became less common compared to bilateral symmetry.

Question 29

What happened to the Carpel over time?

Answer 29

Tended to be inferior to flower rather than superior - generally primitive in early angiosperms.

Question 30

What developed over time with insect evolution?

Answer 30

Nectaries.

Question 31

What did early/simple plants use for survival and reproduction?

Answer 31

Spores (2n) and water borne gametes (n).

Question 32

What is the problem of early plant reproduction traits?

Answer 32

Require water and humid environments, only work in close proximity.

Question 33

What are pollen grains?

Answer 33

Male gametophytes.

Question 34

Characteristics of pollen grains?

Answer 34

Carried by wind, water or pollinator, protected from desiccation, not dependant on water, grow pollen tube to reach female gamete.

Question 35

What does sperm in Cycads and Gingko still possess?

Answer 35

Flagella to swim down pollen tube to female gamete.

Question 36

How has pollen evolved?

Answer 36

Complex and specialised, resistant to desiccation, light and transferable, distinct 3D shape.

Question 37

How has dispersal of pollen changed to overcome major challenge?

Answer 37

Initially wind dispersal, eventually animal pollinators used.

Question 38

Give advantages of wind pollination.

Answer 38

Happen at any time, not reliant on another spp, long distances, continuous.

Question 39

Give disadvantages of wind pollination.

Answer 39

Slim chance finding target, huge amounts required, no direction, close range effectiveness, sticky stigma needed.

Question 40

Give advantages of pollenators.

Answer 40

Efficient, high volumes, large distances, less required, more certainty.

Question 41

Give disadvantages of pollenators.

Answer 41

Costly to produce floral structures, development of complex structures, species loyalty, seasonal reliance, resource vs benefit.

Question 42

Has co-evolution between plants and pollenators been shown?

Answer 42

Yes, strong suggestions.

Question 43

Explain the co-evolution of flowers and insects.

Answer 43

Coevolved with particular pollinators, uniquely structured flowers, attractive features to particular pollinator, shaped to cover with pollen.

Question 44

What is the plant vs pollinator arms race?

Answer 44

Plant wants to be promiscuous but frugal, pollinator wants to be well-fed and lazy.

Question 45

Explain the plants side of the arm race.

Answer 45

Lots of pollen spread, low energy waste on encouraging pollinators, maximum transfer, make pollinator work.

Question 46

Explain the pollinators side of the arms race.

Answer 46

Lots of food for minimal effort, maximal amount of nectar, minimal energy expenditure.

Question 47

What do seeds contain?

Answer 47

Diploid embryo that will germinate into sporophyte, storage tissue, protective coat, hardened tissue to prevent desiccation.

Question 48

What is urbanisation in plant evolution?

Answer 48

Changing conditions and ecosystems require adaption to changes in plant distribution and pollinator availability.

Question 49

What is climate in plant evolution?

Answer 49

Warming environment will need to lead to change in local structures, flowering times, species re-adaptation.

Question 50

What is dispersal by human causing hybrids in plant evolution?

Answer 50

Subspecies of plants hybridise easily, movements of plants and seeds around the world increases chances of hybrids being formed.