Introduction to Biology. Lecture 31
Alexey Shipunov
Minot State University
April 21, 2017
Shipunov (MSU)
BIOL 111
April 21, 2017
1 / 19
Outline
1
Questions and answers
Exam 4
2
Where we are
Life cycles
From Carboniferous to Permian
3
How plants got their seeds
Origin of seed plants
Shipunov (MSU)
BIOL 111
April 21, 2017
2 / 19
Outline
1
Questions and answers
Exam 4
2
Where we are
Life cycles
From Carboniferous to Permian
3
How plants got their seeds
Origin of seed plants
Shipunov (MSU)
BIOL 111
April 21, 2017
2 / 19
Outline
1
Questions and answers
Exam 4
2
Where we are
Life cycles
From Carboniferous to Permian
3
How plants got their seeds
Origin of seed plants
Shipunov (MSU)
BIOL 111
April 21, 2017
2 / 19
Questions and answers
Exam 4
Questions and answers
Exam 4
Shipunov (MSU)
BIOL 111
April 21, 2017
3 / 19
Questions and answers
Exam 4
Results of Exam 4: statistic summary
Summary:
Min. 1st Qu. Median
38.00
52.00
60.00
Grades:
F
D
C
B max
< 60 < 70 < 80 < 90 100
Shipunov (MSU)
Mean 3rd Qu.
60.94
66.00
BIOL 111
Max.
100.00
NA’s
12
April 21, 2017
4 / 19
Questions and answers
Exam 4
Results of Exam 4: the curve
Density estimation for Exam 4 (Biol 111)
40
60
(F)
80
90
(B)
100
Points
Shipunov (MSU)
BIOL 111
April 21, 2017
5 / 19
Questions and answers
Exam 4
Results of Exam 4: sections
100
Competition between Biol 111 sections (Exam 4 )
90
●
●
40
50
60
70
80
●
●
111−5
Shipunov (MSU)
111−2
111−1
111−3
BIOL 111
111−10
111−9
111−6
April 21, 2017
6 / 19
Questions and answers
Exam 4
Results of Exam 4: two questions
A
Roughly speaking, you have 23 father’s and 23 mother’s chromosomes.
In the each of your gametes, there are _ chromosomes:
A. 23 are from your father, 23—from mother
B. 11 mother’s and 12 father’s
C. From 1 to 23 are father’s and from 23 to 1 are mother’s
B
In meiosis, X-shaped chromosomes:
A. Never split
B. Split in anaphase I
C. Split in anaphase II
Shipunov (MSU)
BIOL 111
April 21, 2017
7 / 19
Questions and answers
Exam 4
Results of Exam 4: second pedigree
44. Is the disease from the pedigree chart below:
A. Dominant
B. Recessive
C. I need more information
Shipunov (MSU)
BIOL 111
April 21, 2017
8 / 19
Where we are
Life cycles
Where we are
Life cycles
Shipunov (MSU)
BIOL 111
April 21, 2017
9 / 19
Where we are
Life cycles
Life cycle of multicellular organism
Vegetative
reproduction
n
Sexual
reproduction:
M
Syngamy
n
Gametangium
Y!
n
–
cl
e
+
Gametes
(h
u
m
an
)
lif
e
cy
n
n
General (sporic) life cycle
G
am
et
ic
Haplont
Diplont
Vegetative
reproduction
n
Zygote
Asexual
reproduction:
Spore
2n
Meiosis
R! 2n
n
Spores
n
Sporangium
Zy
go
tic
Shipunov (MSU)
2n
BIOL 111
life
cyc
le
April 21, 2017
10 / 19
Where we are
From Carboniferous to Permian
Where we are
From Carboniferous to Permian
Shipunov (MSU)
BIOL 111
April 21, 2017
11 / 19
Where we are
From Carboniferous to Permian
From Carboniferous to Permian
Devonian period: 419 Mya
Carboniferous period: 358 Mya
Permian period: 299–252 Mya
Shipunov (MSU)
BIOL 111
April 21, 2017
12 / 19
Where we are
From Carboniferous to Permian
Carboniferous period
Hot, wet tropical climate in Europe and North America (Laurasia), dry
arctic forests in Siberia (Angarida)
Pteridophyte and primitive seed plants forests dominated tropics, insects
started to fly
Reptiles appeared
Shipunov (MSU)
BIOL 111
April 21, 2017
13 / 19
Where we are
From Carboniferous to Permian
Permian period
Last period of Paleozoic era, ended with a mass extinction in the sea
and also on land
Pangea formed, with a giant central desert
Primitive synapsid reptiles dominated the land
Shipunov (MSU)
BIOL 111
April 21, 2017
14 / 19
Where we are
From Carboniferous to Permian
Following the movie: reptiles, mammals and birds
Shipunov (MSU)
BIOL 111
April 21, 2017
15 / 19
How plants got their seeds
Origin of seed plants
How plants got their seeds
Origin of seed plants
Shipunov (MSU)
BIOL 111
April 21, 2017
16 / 19
How plants got their seeds
Origin of seed plants
Life cycle of land plants
Sporic life cycle with interleaving generations
Diploid stage grow directly on the haploid stage and even is the
parasite of it (e.g., in mosses)
Originates from the life cycle of algae: diploid stage was an
adaptation to the distribution of spores
Eventually, diploid stage begin to dominate the life cycle
Shipunov (MSU)
BIOL 111
April 21, 2017
17 / 19
How plants got their seeds
Origin of seed plants
The conflict between size and reproduction
Competition for the light resulted in growing up; growing up
resulted in secondary thickening—trees appeared
Seed plants started as trees, and these trees were diploid stage
Haploid stage still existed and probably was a minute prothallium
Diploid stage followed the K-strategy (slow and smart) whereas
haploid prothallium followed the r-strategy (random explosions)
This is a conflict: diploid stage cannot adapt better because free
haploid stage was too cranky, it became a hindrance on the way of
evolution
Decision: take haploid stage on the diploid stage and grow it
inside
Shipunov (MSU)
BIOL 111
April 21, 2017
18 / 19
How plants got their seeds
Origin of seed plants
For Further Reading
Reptiles.
http://en.wikipedia.org/wiki/Reptile
Permian.
http://en.wikipedia.org/wiki/Permian
Shipunov (MSU)
BIOL 111
April 21, 2017
19 / 19