An Orchard Invisible (1-5; 7-10)

Question 1

CH 1 summary

Answer 1

inspirations from seeds; they hold many possibilities ( a few examples like coffee)

Question 2

Animals had 3 movements to land. Plants had..

Answer 2

one movement to land, probably because it was so difficult

Question 3

What 2 major obstacles did plants have to account for when moving from sea to land?

Answer 3

How can sperm swim How can fertilized eggs avoid drying out?

Question 4

How did mosses and ferns adapt to land?

Answer 4

They stayed in damp areas for sexual reproduction In mosses and ferns, the sperm need a film of moisture to swim to the egg from the male organs.

Question 5

How did ferns adapt to land?

Answer 5

Large plants are asexual- they produce spores that fall to the ground beneath them and form a microscopic sexual stage. This micro stage produces the eggs and sperm (the gametophyte stage) The resulting emrbyo takes root and develops into the large fern plant in the sporophyte stage. note: marine algae sometimes have this sort of asexual-sexual phasing so it’s not that odd.

Question 6

All land plants produce..

Answer 6

multicellular embryo that is retained within maternal tissue. This is why they’re all known as embryophytes (aka plants with embryos)

Question 7

How did land plants adapt to make sure the fertilized eggs don’t dry out?

Answer 7

EMBRYOS the evolution of the seed to prevent desiccation this liberated plants from the dependence on a watery environment Males had to find a new way to get sperm to eggs: developed the pollen grain.

Question 8

Earliest seed plants

Answer 8

gymnosperms (360 MYA) living members: ginkos, cycads, conifers “naked seed”

Question 9

Ginkgo biloba unique reproduction

Answer 9

last remaining rep of an ancient type of gymnosperm Reproduction: unfertilized seeds dangle from female tree seed releases a mucilage down, which catches male pollen. Juvenile males and females mature within the seed (pollen arrival triggers ovule development; males parasitically draw nutrition from a tube in the seed) When egg is mature, female floods the pollination chamber with liquid (creates its own ocean) Sperm cell swims to egg using lots of cilia

Question 10

Conifer gymnosperm sexual reproduction

Answer 10

pollen grains come into the conifer ovules (CONES) that flex open and then close when pollen is inside. Conifers have tubes that feed the male and also grow into a conduit for the sperm to reach the egg.

Question 11

Angiosperms developed a new way to feed embryos. It was the..

Answer 11

endosperm when two sperm enter the ovule, they both fertilize an egg (one 1N, the other 2n). The 2M:1P “kid” becomes the endosperm which feeds the viable embryo when it begins growth

Question 12

Why is the endosperm evolutionarily favored?

Answer 12

it is genetically similar enough to the surviving embryo that by sacrificing itself, it is increasing the likelihood of passing on very similar genes.

Question 13

Parental vs. maternal competition

Answer 13

Maternal: resources should be shared equally paternal: grab all the resources possible for his seed endosperm mediates the conflict because it is the supply line as well as the food store through which the mother nourishes the embryo. 2m:1P rules in the end because the embryo is big enough and the food storage is big enough just the ratio matters, not the actual chromosome numbers

Question 14

Ch 3 beginning: What methods of sex do plants do?

Answer 14

sexual and asexual. most plants have methods for both.

Question 15

what circumstances generally lead to asexual reproduction in plants?

Answer 15

when the species is invasive in a new location when they are occupying a territorial edge (can’t necessarily expand in any direction) they are endangered species and didn’t have sexual success (maybe a lot of inbreeding)

Question 16

What was the thought on reproduction of plants during the englightenment (1600s-1700s)

Answer 16

There were ovists and there were spermists. Both thought that either ova or sperm contained the embryo; not that they were both necessary for genetic combination and embryo formation. Each case turned out to be true in one way or another. Ova that develop without sperm are more common than sperm that develop without any contribution of female genes.

Question 17

What happened when Camerarius removed some female silks from corn plants?

Answer 17

no corn seeds developed under that so it basically proved that the female portion of the plant was necessary for something

Question 18

How did Linnaeus classify plants?

Answer 18

based on the likeness and differences of their sex organs

Question 19

What did ovists believe?

Answer 19

that sperm merely stimulated eggs to bring forth its embryo

Question 20

What is the example of a plant that propogates its genes only by sperm?

Answer 20

the Sahara cypress the sperm has double set of chromosomes embryo in the seeds of the sahara cypress is a clone of its father first reported case of surrogate motherhood in the plant kingdom but it’s more of a parasitism this is a bad method because it basically is causing them to die out- there’s not enough selective pressure to also form the female plant organs so therefore NO plant babies are made. -“selfish gene”

Question 21

What is the asexual reproduction of seeds called?

Answer 21

apomixis Products have a double set of maternal chromosomes instead of the set from each parent. Seeds in some apomicts still require pollination to stimulate seed development (even tho sperm don’t contribute genes)

Question 22

Sex vs. cloning in plants (compare, contrast)

Answer 22

Both propogate plant One propagates the parent, the other propagates the species via genetic recombination. Apomixis occurs in endangered, invasive species that have failed at proper sexual reproduction or lack partners. Sexual reproduction is only possible if there is a way to get pollinated without too much inbreeding, which leads to less fit individuals.

Question 23

Why are water plants more successful at asexual reproduction?

Answer 23

their vegetative fragments can be carried way far away to establish new populations hard to distribute on land

Question 24

How do some apomictic seeds get around issues of dispersal?

Answer 24

seeds like dandelions are still able to be dispersed pretty far to start new colonies

Question 25

Ideal asexual plant

Answer 25

rare, alien, aquatic apomict living in a geographically marginal habitat

Question 26

Two theories of why sex is universally successful

Answer 26

1. Morgan: sex provides an accumulation of beneficial genes from a wide network of ancestors -asexual beings have no ancestors, just a straight lineage. 2. Muller: genetic isolation means that deleterious mutations can accumulate within a clonal lineage -whoe clonal lineages must be removed in the interest of deleting bad genes.

Question 27

Comparison of genetic mutations to Muller’s ratchet

Answer 27

mutation load can move in only one direction-up

Question 28

Chapter 4: what is the true reason for flowers?

Answer 28

the aid in pollination and as sexual ornaments flowers are adapted to produce seeds and propagate the species

Question 29

What did Darwin predict about the Madagascar orchid that turned out true?

Answer 29

it had an extra long nectar tube that was pollinated by a special madagascar moth with really long tongues. This wasn’t proven for a long time but it shows how pollinators and plants coevolve.

Question 30

What did Darwin find about cross-fertilization?

Answer 30

It produces plants that are superior in height and vigour to self-fertilized plants showed why it is advantageous for plants to produce elaborate flowers to promote “outcrossing”

Question 31

what is outcrossing?

Answer 31

cross fertilization between flowers; oppositve of self-fertilization.

Question 32

After realizing what inbreeding did to plants, what did Darwin do?

Answer 32

He tried to get British parliment to gather information about first-cousin marriages in the census and the number of living children- he thought his own daughter died from bad genes for this reason.

Question 33

Yucca and yucca moth

Answer 33

example of a moth that parasitized the yucca with its own eggs. The female moth had special mouth parks to carry pollen and it would purposely pollinate the yucca flowers, but it would also lay its eggs. Some cheats lay their eggs in fruit that have already been pollinated so that the yucca won’t abort the fruit. Cheats can triple the numbers of seeds lost to moth larvae

Question 34

What did Charles Riley do that was unique?

Answer 34

He proposed that grafting north american grape vines with french ones would help confer the resistance that NA vines had to a certain aphid that was eating the roots.

Question 35

Talk about the figs

Answer 35

they have a unique method of pollination that has become big business They are pollinated by tiny wasps that parasitize the flowers. The plants maintain control at all times which is why it’s successful. The fig is actually an unopened flower receptacle that the wasps live in. They live in the neuter figs that serve as brood chambers. Each wasp species is unique to each type of fig tree. Sometimes the wasps can pollinate other figs up to 10 km away (the females leave and pollinate other fig trees when its time to lay their eggs) Every coevolved relationship is susceptible to subversion (cheating wasps, seed parasites, parasites of fig wasps)

Question 36

review mendelian inheritence ratios (3:1 phenotype and stuff)

Answer 36

encompasses all of ch 5 notes

Question 37

Chapter 7: seed size. Explain the double-coconut “Coco de mer” and why it was so odd.

Answer 37

They were found on the shores of Maldive, 2300 km away from their home in Seychelles.

Biggest seed ever known.

Not designed for travel even though it floats everywhere

Probably evolved for dry habitats

Because of its need to compete for light in a wetter/ more hospitable changing climate, selection favored bigger seeds.

^that got out of hand.

it developed a “rope” that left the seed underground and popped up 10 meters away for dispersal since the seeds were too heavy

Consequences to the tree are that the crown is so heavy that it can just break and die. oops.

Question 38

seed size of palms compared to seed size of herbaceous plants

Answer 38

palms tend to have seeds that are much larger (400xs) than respective herbaceous plants

Question 39

When would natural selection favor many smaller seeds over a few larger ones?

Answer 39

1. if circumstances permit smaller seeds to survive
2. if competition from trees is checked by disturbance

Question 40

Chapter 8: “number” of seeds: What is masting? Why do trees do this?

Answer 40

Masting is when, due to subtle weather/environmental cues, certain types of trees produce TONS of seeds one year at the cost of growth in the coming years

This is a situation of predator satiation; the trees attempt to feed all their predators AND have enough seeds left over to germinate and form new offspring. They do this instead of letting all their meager amounts of seeds be eaten every year.

They hope that the squirrel that buried their acorns dies, forgets about them, and then they germinate.

Also adapt to squirrels biting off the tips of the acorns by moving the embryo (offset)

Question 41

Tell a story:
White footed mice, gypsy moths, and acorns.

Answer 41

Act 1: mice eat acorns one year. Get fat, live through winter, have TONS of babies.

Act 2: summer hits. not many acorns around. Mice are hungry; they eat gypsy moth pupae.

aside: gypsy moth caterpillars eat oak buds

Act 3: the foliage on the oaks are saved. There are more acorns that survive. Oaks are happy with the mice and reward them with surviving to make more mast years.

Question 42

Tell a story:

Lyme disease, spirochete, acorns

White-footed mice, white-tailed deer

Answer 42

White footed mice are resevoirs for spirochete which cause lyme disease

Acorn mast years = more mice. Ticks go from mice to deer.

Ticks that bite mice get the spirochete. Humans wander through forests after a mast year when there were lots of mice therefore lots of ticks.

Human gets tick.

Human gets spirochete-induced lyme disease.

Human gets arthritis and floaters.

Hopefully, the tick finally finds a white-tailed deer which is its second typical host.

Question 43

What is fruit responsible for in humans/animals?

Answer 43

primate color vision

Question 44

Why are fruit so inviting for dispersal?

Answer 44

long range dispersers always win in the long run because they are able to colonize far away places, when the plant that didn’t even try has a 0% chance of increasing its range and avoiding extinction

Question 45

Mistletoe story

Answer 45

Has a symbiosis with a special bird; produces berries that are really sticky that can survive the bird’s gut.

When the bird is fed on mistletoe, the seed is on its body or in its body; either way the sticky stuff ends up sticking to a branch with the seed in the end.

Great example of directed seed dispersal

Question 46

Majority of mammals have what type of color vision?

Answer 46

two-cone

Question 47

Why is it advantageous for mammals to have 3-color vision?

Answer 47

because we’re better at spotting things that are red against a green canopy; we can find fruit.

Question 48

When did we evolve color vision?

Answer 48

when daylight was no longer dominated by reptiles (after the mesozoic?)

Question 49

Proposed theory for developing 3 color vision

Answer 49

a duplicated section for opsin on the X chromosome mutated for a different wavelength specificity

Question 50

Chapter 10: what is the importance of dispersal?

Answer 50

Get your seeds out there to colonize new areas

Question 51

Gliders vs. single unilateral wing seeds

Answer 51

gliders work too great in still air, not very good in gusts.

unilateral wings are much more common and have evolved many times in different groups. They use good wing-loading to make them light and bouyant. They have a spinning flight pattern that slows their descent through the air and helps them float upward on drafts.

Question 52

Parachute seeds

Answer 52

bad fliers. Seem to not travel far.

Question 53

“what makes a flying ace?”

Answer 53

low wing loading

chance

released with sufficient wind (maybe propelled); responsive to air turbulence

Question 54

What experiment showed that wind eddies could carry seeds really far?

Answer 54

A central park art exhibit

Question 55

Lodgepole pines and dispersal

Answer 55

Long distance dispersal helped them colonize areas 70 km away from their last point which has helped the species thrive and expand.

Weight and windloading ahve decreased with each subsequent population: shows that they’re selecting for smaller seeds for dispersal.

Question 56

When a plant population colonizes an island, what is likely to happen to their seeds?

Answer 56

they will lose whatever sweet long-distance dispersal mechanism they used to get to the island because it’s using energy for nothing.