Download Notes: Plant Diversity

Plant Diversity & Reproduction
Chapters 22, 24 Notes
I.
Introduction to plants
A. Plant characteristics
a. multicellular
b. eukaryotes
c. cells walls made of cellulose
d. contain chlorophyll – a pigment that gives plants their green
color; found in chloroplasts, which is the location where
photosynthesis occurs
e. autotrophs
f. no movement
g. Examples: trees , ferns, shrubs, grasses, moss
B. Requirements for plants:
a. sunlight – leaves are usually broad and flat to maximize
absorption of light
b. water
c. minerals – nutrients in soil
d. Gas exchange
1. require carbon dioxide (CO2) for photosynthesis
2. require oxygen (O2) for cellular respiration
e. Specialized tissues - carry water and nutrients
C. Plant life cycle – Alternation of Generations
a. Alternation of generations - 2 alternating phases of plants
1. gamete producing phase – gametophyte (N)
2. spore producing phase – sporophyte (2N)
D. Evolution of plants
a. Plants evolved structures to collect, transport, and save water
These special structures allow them to survive on land.
b. 1st plants evolved from algae (a plant-like protist)
c. 1st plants required water for reproduction
E. Development of the four major groups of plants:
F. Mosses (Bryophytes)
a. Nonvascular – do NOT have special tissues that conduct water
and nutrients
b. NO roots- use osmosis to get water
c. require water for reproduction
d. live in moist shaded areas
e. Very small
G. Ferns
a. are vascular – have special tissues that conduct water and
nutrients
b. Types tissue in vascular plants:
1. Xylem – moves water up plant from roots
2. Phloem – moves nutrients through plant from leaves
c. have delicate leaves called fronds
d. have roots
e. require water for reproduction
H. Cone-bearing plants (gymnosperm – “naked seed”)
a. are vascular
b. DO NOT require water for reproduction
c. have seeds – an tiny embryo of a plant, with food inside a
protective covering (p.616 fig 24-9); protects embryo
* d. have male and female cones
e. have pollen – male gamete, containing sperm produced in male
cone
f. pollen is carried by the wind until it reaches a female cone
g. pollination – when sperm from pollen unite with eggs from
ovary to a form seeds
h. most have needle-shaped leaves – allows them survive dry
conditions (conserve water)
i. mostly pollinated by wind
I. Flowering Plants (angiosperm – “enclosed seed”)
a. are vascular
b. DO NOT require water for reproduction
c. have seeds
d. have pollen; go through pollination to form seeds
have flowers – attract insects that spread pollen to other
* e.
flowers
f. have fruit – ovary that contains seeds
fruit attracts animals to eat; seeds pass through animal digestive
* g.
system and end up in soil, ready to sprout
h. mostly pollinated by insects; more successful than wind
pollination
J. Methods of Seed Dispersal
a. animals – provides nutrition to animal; animal’s digestive system
breaks down tough, outer coat of seed allowing it to sprout when it is
excreted in animal waste
b. wind– lightweight seeds; have wing-like structures; also
tumbleweeds contains seeds
c. water - some seeds float on water; ex: coconut
K. Seed dormancy – embryo inside seed is alive, but not growing
a. allows for long-distance dispersal
b. allows seeds to sprout when conditions are good for growth
a. changes in temperature and moisture can cause a seed to end
dormancy
L. Seed Germination – when an embryo inside a seeds starts to grow
and sprout out of the ground
Structure of a flower
A – Ovule (egg)
B – Ovary
C – Style
D – Stigma
E – Stigma (female parts)
F – Anther
G – Stamen (male parts)
H – Filament
I – Sepal
J - Petal
Life cycle of a flowering plant