Unit 4 Notes #3 :Terrestrial Plants and Their
Adaptations To Land
A) Adaptation To Land
- To achieve larger size and to inhabit drier
environments, higher plants needed a better
design than the aquatic plants (Chlorophyta)
and the non-vascular Bryophytes.
Advancements:
1) Development of Vascular Tissues (Xylem
and Phloem) for transport.
For aquatic plants: Water and dissolved
minerals are plentiful and diffuse into the
plant from all sides.
On land: Water is scarce, often found only
underground.
Plants had to develop special tissues to
conduct water from ground level up to their
stems and leaves (these tissues also increase
rigidity)- XYLEM
2) Development of a Cuticle – To Prevents
Desiccation (drying out).
-This cuticle is a waxy covering on leaves and
stem to cut down on water evaporation.
3) True Roots – For absorption and
anchorage.
-Absorb water and minerals from the soil.
-Also for anchorage, no longer buoyed up by
water.
4) Protective Jacket for Gametes (sex cells)
-Keep gametes from drying out
Example:
- Male sperm cell packaged up in pollen
capsule.
- Ovules formed and protected in ovary of
female part.
5) Protection for Embryo (Developing Plant)
-Example: Fruit- keeps embryo from drying
out, also promotes dispersal by passing
through the digestive tract of a given animal.
-Also a proper SEED - embryo with food, and
seed coat.
6) Mechanisms for the dispersal of gametes
and embryos.
In water: Gametes and embryos swim or float
in water currents.
On land: Use wind or rely on certain insects
or other animals for dispersal of male
gametes (pollen).
- After pollination and fertilization, plant still
need to rely on animals or wind to disperse
their embryos (enclosed in seed)
Animal: Eat fruit discard or defecate seed
adequate distance away.
Burrs or hooks catch in the fur and fall
elsewhere.
B) Vascular Plants : The Tracheophytes
Kingdom: Plantae
Phylum: Tracheophyta
Ferns – Subphylum : Pteridophyta The First
Vascular Plants
Pigments: 1) Chlorophyll a
2) Chlorophyll b
Habitat: 1) Tropical and Temperate
Rainforests
2) Have evolved many adaptations so that
they are no longer limited to totally wet
environments. They are still limited to
environments that are at least seasonally wet,
as they use flagellated sperm to swim to the
eggs.
Adaptations:
1) Have vascular tissues.
a) Xylem: Tissue that includes dead
Tracheid cells (hence Tracheophyta), these
cells transports water and dissolved nutrients
from roots to all parts of the plant. These cells
have thick cell walls and provide structural
support for the plant.
b) Phloem: Living cells that transport
nutrients and products of photosynthesis to
all parts of the plant.
2) Strong true roots coming off of rhizomes
(underground runners)
3) True vascular leaves (fronds)
Alternation Of Generations In Ferns:
- Unlike mosses, the Sporophyte (2N) is the
dominant generation and the gametophyte
(1N) is minimized.