BIO220 Lecture 20 Flashcards Preview

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Flashcards in BIO220 Lecture 20 Deck (61):
1

Right now, we are in the ___ period

quaternary

2

Quanternary period

- last 2.68 million years
- ice age with alternating glacial & interglacial periods

3

Humans emerged ___ years ago

2 million

4

Agriculture is a ____ phenomenon, which appeared in the last ___ years. This means that it appeared in a ___ period.

post-glacial (Holocene epoch);
10 000;
inter-glacial

5

we are currently living in the ___ epoch of the quaternary period

Holocene

6

early humans evolved & migrated as...

hunter/gatherers

7

One theory of ____ states that __ and homo sapiens are very similar

hominid evolution and dispersal;
Neanderthals

8

What was the last area to be colonized by homo sapiens?

Americas

9

Why are fruits good foods?

They are supposed to be eaten (by animals for dispersal)

10

Why are seeds & tubers good food?

energy-storing organs (complex carbs & sugars)

11

Humans are not adapted for eating plant foods. The foods that we eat has to be...

- high nutritional quality
- less defended

12

___ selection was used to make plants more edible

artificial

13

agriculture evolved ___

independently in different areas

14

cultural component of agriculture

societies have to learn (from older generation) how to store seeds, weed, plant...

15

lentils have symbiotic relationship with ___ to get ___

bacteria;
nitrogen

16

legumes are good sources of...

plant protein

17

which kind of seeds are best for humans? for plants?

humans: seeds that don't shatter because they are easier to collect

plants: seeds that shatter so it disperses genetic material

18

grasses that we eat

- wheat
- rice
- maize
- barley

19

legumes that we eat

- beans
- lentils
- chick peas

20

fruits that we eat

- tomatoes
- squash

21

What are key evolution innovations for grass agriculture?

- non-shattering seed heads
- amylase evolution

22

ancient agriculture innovations

- fish net
- irrigation channels
- domestication (-> evolution of lactose tolerance)
- plows
- crop rotation, draft animals (Middle Age)
- exchange of crops, animals, technology (1492)
- no more nomadism

23

sedentary culture lead to the development of...

- cities
- agriculture

24

Limits of primitive agriculture

- limited area for growth (temperature > water > NPK)
- edaphic (soil) factors: moisture, fertility
- planting same things in same area -> insects, disease, bad yield

25

Janzen-Connell hypothesis

seeds that fall too close to adult tree will die due to established predators in that area
- keeps too many of the same species growing in the same area

26

The first population boom lead to...

famines

27

who made artificial fertilizers?

John Bennet Lawes of Rothamsted (different concentrations of N, P, K, Mg)

28

How was edaphic factors solved by agricultural sciences?

add things to soil to replenish lost nutrients
- fertilizer (chemicals)
- animal poop add N (organic)

29

Where do organic fertilizers & chemical fertilizers differ?

organic matters will also affect soil texture & water retaining qualities, but chemical ones won't

30

which chemical fertilizers had the best effect?

- nitrates
- ammonia

31

N fertilizers come from...

high nitrate minerals
- saltpeter
- KNO3
- NaNO3

32

Haber-Bosche process

chemical creation of ammonia
natural gas + atm nitrogen + catalyst + pressure -> ammonia

33

HB process produces ___ ammonia per year, and uses ___% of the world's natural gas supply

500 million tons;
3-5

34

consequences of HB process

- mining towns abandoned
- wars, explosives
- 1/2 of N in our bodies is from HB
- meat production
- 1/2 of world is being fed with N from HB

35

How has new technology overcome previous agriculture limitations?

- irrigation brings water to dry areas
- fertilizer supplies soil with nutrients
- industrial chemistry makes fertilizer

36

Life history theory of plants: how has this been affected by new agricultural technologies?

plant allocations can all go towards seed production because humans prevent competition, insect attacks, need for nutrients

37

life history of plants

plants allocate resources to:
- growth (tall = more light, better seed dispersal)
- competition
- defense
- reproduction
- dispersal
- root system: more water & nutrients

38

plant-breeding techniques

- artificial selection
- hybridization

39

the Green Revolution

- used plant breeding techniques to evolve high-yielding dwarf crop varieties (HYV)
- high-intensity cultivating techniques

40

HYV

high yielding dwarf varieties

41

IR8

a semi-dwarf rice variety that could produce more grains of rice per plant when grown with certain fertilizers and irrigation

42

who founded the Green Revolution?

Borlaug

43

HYV are unable to...

detect neighbours
- when plants detect neighbours, they grow tall and skinny

44

Green Revolution techniques lead to a...

exponential rise in yield, but began leveling in mid-1990s
- Green Revolution techniques can't keep up with human growth anymore

45

Now that yields have began to level, how to we support a still-increasing population?

GMO?

46

Consequence of babying plants

- labour intensive
- use exhaustible natural resources w/ limited supplies
- pollution to surrounding areas (groundwater, poison non-target organsims)
- biocides develop superbugs, addictive

47

what is the preferred antibiotic nowadays? Why?

Z-pak;
penicillin is so resistant that it can't be used anymore

48

why don't plants need to worry about competition anymore?

- herbicides
- mechanized cultivation

49

why don't plants need extensive roots anymore?

- irrigation
- fertilizers

50

why don't plants need defense anymore?

- insecticides
- fungicides

51

cultivation & irrigation leads to long-term...

degradation of soils (build-up of salt)

52

which is better: annual wheat vs. perennial wheat

annual wheat: good for people
perennial wheat: good for plant

53

annual wheat

Only lives for 1 year
- Shallow root system
- More yield
- Susceptible to disturbances

54

Perennial wheat

Lives for long time
- Extensive root that can provide soil structure
- More resilient to disturbances
- But less yield

55

2 types of maize production

1. slash & burn
2. mechanized

56

slash & burn vs. mechanized costs & yield

cost: mechanized so much more labour and material intensive
yield: mechanized 4x more

...but is it worth it?

57

modern agriculture depends on..

energy subsidies

58

cost of food is tied to...

cost of petroleum & electricity

59

why is cost of food going up?

we are adding so much stuff in our food to improve yield

60

with current technology, increasing food supply requires...

burning more fuel & clearing more land

61

N, P, K: what is limited?

P & K
P is mined, and very scarce