Grade 11 University Biology – Unit 1 Diversity of Life
Algae to Terrestrial Plants
Section 3.1 (Pages 90-95)
Alga (plural algae) – Unicellular or multicellular photosynthetic aquatic protist
Since they photosynthesize, why are algae not classified as plants?
 See Figure 3.1 on Page 90
 There is no set classification, but green plants did evolve from algae AND green algae is the link
between the two groups
 All unicellular protists can be called algae. There are three phyla of protists: diatoms,
dinoflagellates and euglenoids
Multicellular Algae
 See Figure 3.2 on Page 90
 Multicellular are usually seaweed and classified into three phyla: (1) Rhodophyta (red), (2)
Chlorophyta (green) and (3) Phaeophyta (brown)
Brown Algae (Phylum – Phaeophyta)
 Biggest and most complex
 Key components of tidal and marine environments
 Example – kelp that can form dense “aquatic forests”
 Do not have true leaves or roots
 Have specialized tissues
 Anchors to the bottom via a holdfast
 The stem-like structure is a stipe and flat, leaf-like blades grow to
collect light, intake CO2 and give off O2
Red Algae (Phylum Rhodophyta)
 First multicellular organism on Earth, originating between 1.5 and 1.2 BYA
 Today, 6000 species
 Occur most frequently in warm coastal water of tropical oceans as deep as 100 metres
 Have green chlorophyll and an additional pigment – PHYCOERYTHRIN – that reflects red
wavelengths of light
 Commercially important include carrageenan that holds the components of ice cream together
Green Algae (Phylum Chlorophyta)
 Generally freshwater algae but possible on tree surfaces, fur on animals, sea ice
 Structurally diverse (see Figure 3.5 on Page 92).
 Uincellular or multicellular
 Most plant-like algae including (1) cell walls containing cellulose, (2) food stored as starch, (3)
similar DNA and (4) same types of chlorophyll (chlorophyll a and b)
Nutrient Enrichment
Eutrophication is the long-term, natural process by which lakes gradually age and become more
biologically productive. Through activities that increase plant nutrient levels in water, humans accelerate
the eutrophication process. This is called Anthropogenic Eutrophication or Nutrient Enrichment.
The input of excessive plant nutrients, primarily phosphorus and nitrogen, can increase aquatic plant
growth. It becomes a problem when massive and nuisance “blooms” of microscopic algae occur.
Task
From the following ideas, describe the environmental problems that can arise from algal blooms
1. Algae blooms absorb sunlight.
2. Algae die.
3. Algae contain proteins.
4. Algae blooms form mats of algae on the surface of lakes.
5. Some types of algae are toxic.
Task
Effects of Nutrients on Water Quality - Bay of Quinte Case Study
A case study to examine the relationship between the concentration of phosphorus and algae growth in a
water ecosystem.
 Excessive algae growth in the Great Lakes, and in particular, the Bay of Quinte is a severe water
pollution problem. Algae cloud the water and prevent light from preventing. As a result,
submerged aquatic plants cannot grow. The proteins in algae add a bad taste and odour to
drinking water. A large, floating mass of algae is not attractive, and when it dies and decays,
strong odours are present.
 The concentration of phosphorus can be measured in water. Concentrations of phosphorus are
expressed in micrograms per litre (μg/l).
 The amount of algae, often referred to as productivity, is determined as the volume or density in a
water sample. Algae growth can also be calculated by estimating light penetration into the water
column. Finally, the amount of cholorphyll (produced during plant photosynthesis) can be used to
estimated algae mass or productivity.
Instructions
 Answer all questions
 Make graphs of the data as follows: (1) three line graphs (one for each station) to examine the
relationship between phosphorus and algae. The x-axis is Year. The LEFT Y-axis is Mean Total
Phosphorus (μg/l) and the scale should go from 0 to 100. The RIGHT Y-axis is Algae Density
(mm3/l), and the scale should read from 0 to 16 and (2) two line graphs to compare between
stations. One graph should illustrate Total Phosphorus. The other graph will be Algae Density.
 Provide your interpretation of the graphs
1. Algae growth can be calculated by measuring the depth of light penetration in the water column. How
can light penetration provide information about growth? Provide your thoughts.
2. The volume of chlorophyll is also used to estimate algae productivity. What is the relationship to
make this estimation? Provide your thoughts.
Three sampling stations have been established to examine the relationship between phosphorus
concentrations and algae growth in the Bay of Quinte.
 Upper Bay – located near Belleville. Water depth is very shallow and the current is slow moving
 Middle Bay – located between Napanee and Picton in an area called Long Reach. Water depth is
deep, water movement is faster that Upper Bay, and additional water is added from the Napanee
River and Hay Bay
 Lower Bay – located in the Adolphus Gap where Bay of Quinte water mixes with Lake Ontario
water, the water is very deep and cold, and the water current is fast.
Questions
 What trend(s) can you find that are common on all three graphs? What does that suggest about
the relationship between phosphorus and algae?




Comparing between stations, what differences and similarities can you detect? From the
summary information above, provide possible explanations for your observations.
Why is a long-term dataset valuable?
Some data points do not seem to follow the general trend. Why might account for these
differences?
Actions to control phosphorus inputs were introduced in 1978. Did they work?
Table 1. Total Phosphorus Concentrations (μg/l) and Algae Densities (mm3/l) for three stations in the Bay
of Quinte between 1972 and 1994
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
70
90
79
89
70
70
48
46
47
51
50
53
54
51
31
37
46
39
39
40
31
39
36
13.1
10.1
12.7
16.1
14.0
12.5
4.3
7.1
9.4
5.5
8.5
7.4
10.5
13.3
6.7
9.0
9.1
6.2
5.3
8.3
7.0
6.3
8.2
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
63
52
50
56
45
47
40
34
38
46
46
44
46
42
35
31
33
40
29
29
30
32
28
8.4
7.1
7.8
9.8
10.9
8.3
4.2
4.7
6.0
5.4
8.5
9.9
9.1
5.5
6.9
7.2
9.8
7.3
6.2
5.2
6.9
5.8
7.3
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
Task
Do Activity 3.1 “How might Climate Chage affect Giant Kelp?” on Page 92
23
23
24
20
20
19
18
21
23
24
19
19
18
18
14
11
20
16
13
11
19
13
11
Algae Density
(mm3/l)
Mean Total
Phosphorus (μg/l)
Year
Station C
Lower Bay
Algae Density
(mm3/l)
Mean Total
Phosphorus (μg/l)
Year
Station B
Middle Bay
Algae Density
(mm3/l)
Mean Total
Phosphorus (μg/l)
Year
Station A
Upper Bay
3.3
2.1
1.9
2.3
3.0
2.3
1.8
0.9
1.8
1.3
1.1
1.5
1.9
1.3
1.4
1.7
1.8
0.9
1.7
1.2
1.4
2.1
1.4
Shift to Land
 Green plants are the closest evolutionary links to terrestrial plants (see above for similarities)
 Movement to land occurred about 460 MYA
Why would plants move to land? Provide your hypothesis.
Adaptations
 Early land plants were (1) very small, (2) grew in moist places and (3) transferred water and
dissolved substances from cell to cell by inefficient osmosis and diffusion
 Reproduce using plant embryos – an organism’s early pre-birth stage of development; small,
simple, multicellular plants dependant on the parent plant for a period of time
 Vascular tissue for transporting materials (e.g., xylem for
water movement up into plant). With lignin in the xylem
tissue, plants could also grow tall. The vascular tissue
also specialized. Roots developed to anchor the plant
and allowed for greater material uptake. Leaves
developed to increase photosynthetic surface area and
improve gas exchange with the environment (i.e.,
evolution of stomata)
 Flowers that aid in reproduction. Flowers hold both male
and female parts, and as such, provide a site for
fertilization
 Seeds for embryo protection
 Reproduction with ALTERATION OF GENERATIONS or
sporic reproduction where there are two stages in the life cycle: (1) gametophyte is the haploid
plant that produces gametes via mitosis and (2) sporophyte when the gametes fuse to develop a
diploid cell that produces spores via meiosis which form a new gamete (see Figure 3.8 on Page
94)
 See Figure 3.7 on Page 94