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Evolution of Plants
The Nitrogen Cycle
• Matter is ____________________ in the environment within and between ecosystems.
• All organisms require ______________________ to make:
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•
•
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Although nitrogen gas is the most abundant form of nitrogen on Earth, only certain types of
______________________ that live in the soil and on the roots of legumes can use this form directly.
The bacteria convert nitrogen gas into ______________________, in a process known as
_________________________ _____________________.
Other soil bacteria convert fixed _____________________ into nitrates and nitrites that plants can use to
make proteins and nucleic acids.
Heterotrophs eat:
The First Land Plants
• The greatest challenge that early land plants faced was:
•
They met this challenge by:
•
Fossils suggest the first true plants were still dependent on ___________________ to complete their life
cycles.
One of the earliest fossil vascular plants was ____________________, shown here.
Several groups of plants evolved from the first land plants.
• One group developed into _____________________.
• Another lineage gave rise to:
•
•
An Overview of the Plant Kingdom
• Botanists divide the plant kingdom into five major ________________ based on four important features:
• 1.
• 2.
• 3.
• 4.
Draw the plant Cladogram
Vascular Plants
• Vascular tissue—xylem and phloem—make it possible for vascular plants to:
Vascular plants are known as __________________________, after a specialized type of water-conducting cell
they contain.
• These cells, called ___________________, are hollow tubelike cells with thick cell walls strengthened
by lignin.
Xylem
• Tracheids are found in xylem, a tissue that carries __________________ upward from the roots to every
part of a plant.
•
Phloem
• Vascular plants also have a second transport tissue called phloem that transports solutions of
___________________ and _______________________ produced by photosynthesis.
Seedless Vascular Plants
• Among the ___________________ vascular plants alive today are three phyla commonly known as club
mosses, horsetails, and ferns. The most numerous of these are the ferns.
• Ferns can thrive in areas with little light and are most abundant in _______________ habitats.
• Explain two advantages that vascular tissue gave plants.
1.
2.
The Importance of Seeds
• Every _________________ contains a living plant ready to sprout as soon as it encounters the proper
conditions for growth.
• The production of seeds has been one key to the ability of plants to ____________________ even the driest
environments on land.
Seed Plants
• A seed is a plant _________________ and a ______________ supply, encased in a protective covering.
Cones and Flowers
• In seed plants, the male __________________________ (sex cells) and the female gametophytes grow and
mature directly within the _________________________(adult plant cells).
• The gametophytes usually develop in _____________________ structures known as cones or flowers.
• Nearly all ________________________ bear their seeds directly on the scales of cones.
• Flowering plants, or _______________________, bear their seeds in flowers inside a layer of tissue that
protects the seed.
Pollen
• In seed plants, the entire male gametophyte is contained in a tiny structure called a __________________
________________
• Pollen grains are carried to the ____________________ reproductive structure by wind or animals such as
insects.
• The transfer of pollen from the male reproductive structure to the female reproductive structure is
called _______________________.
• Pollen in gymnosperms must be carried by the ___________________.
• Pollen in angiosperms is mostly carried by :
Seeds
• After fertilization, the __________________ contained within a seed grows into a tiny plant—the
sporophyte embryo.
A tough seed coat surrounds and protects the embryo and keeps the contents of the seed from
_____________________ out.
• The embryo begins to grow when ____________________ are right. It does this by using nutrients from the
stored food supply until it can carry out photosynthesis on its own.
Angiosperms
• Angiosperms –
Flowers and Fruits
• Angiosperms develop unique reproductive organs known as __________________, shown in the figure.
• Flowers contain _____________________, which surround and protect seeds.
Advantages of Flowers
• Flowers are an evolutionary advantage to plants because they ___________________ animals that carry
pollen with them to the next flower they visit.
• This means of pollination is much more efficient than the _________________ pollination of most
gymnosperms.
Fruit
• After pollination, the ovary develops into a __________________, a structure containing one or more
matured ovaries.
• When an animal eats a fleshy fruit, seeds from the fruit enter the animal’s ___________________ system.
By the time the seeds leave the digestive system, the animal may have traveled many kilometers.
• By using fruit, flowering plants increase the _______________ they inhabit.
•
Describe two advantages that gymnosperms have over bryophytes (nonvascular land plants) and two
advantages that angiosperms have over gymnosperms.
Cotyledons
• Seed leaves in their _____________________
o __________________ – 1 seed leaf
o __________________ – 2 seed leaves
Angiosperm Classification
• Scientific classification places the monocots into a single group but places the dicots in different
categories.
• The characteristics of monocots and dicots are compared in the table below.
Annuals, Biennials and Perennials