Evolution

Tracheophytes

(vascular plants)

Bryophytes (non-

vascular plants)

Seeded

Seedless

Angiosperms

Gymnosperms

FernsClub mosses

Mosses

Hornworts

Liverworts

Fresh

water

alga

Why did humans become farmers and

not remain hunter/foragers?

When Did Crops Evolve

Time

period

Evidence of crop cultivation

> 5,000

years

pea, barley, wheat, maize, millet,

lentil, beans, , rice, potato.

1,000 to

5,000

years

Sugar beet, sunflower, soybean,

alfalfa, onion, cotton.

< 1,000

years

rapeseed, coffee, rubber, macademia

nut.

.

sugarbeet,

rapeseed

.

.rice,

soybean

.millet,

coffee.

cotton,

rubber

.

.potato,

maize, bean

.

sunflower

.alfalfa,

apple

.

.

Macademia

barley, wheat,

lentil, pea

Potato

Solanum tuberosum ssp tuberosum

2n = 4x = 48

Named Solanum

tuberosum by Casper

Banhin in 1596

South American

Indian called the

crop papa. The

name potato comes

from the Caribbean

Aeawak Indian

word batata

Why are the world record potato

yields in Idaho and Holland?

How did the potato crop evolve

so quickly?

How did the potato evolve

from this to this is a very short

period of time?

1992

How did crop

evolution happen

Genetic Variability

Selection Pressure

Charles Darwin

Born in England,

educated in Scotland.

The father of evolution

Most famous for his

travels on the Beagle to

the Galapagos Islands.

“Survival of the fittest”.

Wrote The Origin of

Species.

DomesticatedWild

Crop Domestication

“Natural selection favors plant types which would have greatest chance of survival, reproduction, and distribution of progeny”

“Human selection is the result of conscious decisions by the farmer or plant breeder to keep progeny from a certain parent over others”

Greater progeny dispersal: cereals, potato, strawberry.

Altered seed/tuber dormancy: oats, rice, beans, onion, carrot.

Increased spininess: pineapple, lettuce, egg plant.

Increased toxicity in seeds and fruits: bean, potato, tomato.

Less branched, fewer inflorescence more determinant growth: most cereals, sunflower, hemp.

Reduced spininess: sisal, pineapple, lettuce, yams.

Develop of attractive colors: most fruit, maize, pulses, peppers, potato.

Development of quality for multiple uses: most crops.

Increased yield: all crops.

Increased resistance to pests and diseases: all crops.

Reduced plant size (dwarfism): wheat, barley, peach, etc.

Shorter lifecycle (towards annual crop): rye, cotton, etc.

Ploidy describes the number of chromosome sets in each cell.

Most agricultural crops are diploids.

Agriculturally important crops include alloploids and autoploids.

Diploid

X

2n = 2x = 6 2n = 2x = 6

2n = 2x = 6

Barley

Apple Corn

Carrot

Allopolyploidy

X

2n = 2x = 6 2n = 2x = 8

2n = 4x = 14

Wheat

Cotton Canola

Sugarcane

Autopolyploidy

X

2n = 2x = 6

4n = 4x = 12

2n = 2x = 6

PeanutPotato

CoffeeStrawberry

Domestication has been taking place

continually for over 9000 years, at

roughly constant rate

Where did

domestication occur?

Domestication and crop

evolution has occurred, and is

still occurring, wherever

agriculture was practiced

All sorts of people, from early

farmers, to modern-day

farmers and plant breeders

How did these crops evolve?

Selection in crops has been a

combination of natural and human

selection a process similar to

Darwinism

Put things into prospective.

Centers of crop origins is often associated

weedy relatives.

Weedy relatives have ‘desirable’ traits

that we introgress into our new crops.

Knowing how and where are crops were

developed helps to know how best to

proceed in the future.

Food