Download Plant and Animal Life Cycles

Plant and Animal
Life Cycles
Chapter 6
7th grade
6.1 Vocabulary Terms
• Angiosperm, a plant
having its seeds enclosed
in an ovary; a flowering
plant
• Root cap
• Cambium
• Xylem
• Phloem
• Zygote
• Embryo
• Cotyledons
• Seed dispersal
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Germination
Flower
Pollination
Sepals
Petals
Stamens
Filament
Anther
Pistils
Stigma
Style
Ovary
Functions of Roots (pg 195)
• Roots anchor a plant, absorb water and
minerals, and sometimes store food.
• Types:
– Fibrous root system: similarly sized roots that
form a dense tangled mass (grass)
– Taproot: one long thick main root that is hard to
pull out of the ground (carrot)
• Structure: Root cap, root hairs, vascular
tissue (xylem & phloem)
Stems (pg 196)
• Stem carries substances and provides
support.
• Types:
– Woody: hard and rigid
– Herbaceous: no wood, soft
• Structure:
– Bark (woody): out protective layer (cork), inner
layer of phloem
– Cambium
– Sapwood (active xylem) and heartwood (inactive
xylem)
Annual Rings (pg 197)
• In spring, the xylem are large and thin
because they grow rapidly and produce
wide, light brown rings.
• In summer, they grow slowly and so are
small and have thin, dark rings.
• Tree’s age is found by counting the rings.
• Rainy years, the rings are wide. In dry
years, they are narrow.
Leaves (pg 198)
• Leaves capture sun’s energy and carry out
photosynthesis.
• Structure:
– Top and bottom layers that protect the veins of xylem and
phloem
– Stoma open and close to control when gases enter
(carbon dioxide) and leave (oxygen and water vapor)
– Close stomata to retain water and prevent transpiration
• Photosynthesis:
– Cells with most chloroplasts are near the upper surface to
get most light
– Water comes in from the xylem, sugar is transported
through phloem
Seeds Become New Plants (pg 200)
• Seed structure:
– Embryo begins to grow and uses food stored until it can
make its own
– Stored food can be in the cotyledons or outside them
– Seed coat protects the embryo from drying out
• Seed dispersal- farther from a parent has a better
chance of survival because it doesn’t have to
compete for light, water, or nutrients
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Pass through animal digestive systems
Barb-like structures that hook onto fur or clothing
Water, wind spread seeds
Some plants eject the seeds
• Germination- seed absorbs water and roots grow
down and stem grows up.
Flowers (pg 202)
• The colors and scents produced by flowers
attract animals to pollinate.
6.2 Vocabulary
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Sporophyte
Gametophyte
Annual
Biennial
Perennial
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Fertilization
Cone
Ovule
Fruit
Gymnosperms are a
taxonomic class that
includes plants whose
seeds are not enclosed in
an ovule (like a pine
cone). Gymnosperm
means as "naked seed"
Stages of Plant’s Life Cycle (204)
• Plants have complex life cycles that include
two different stages, the sporophyte state
and the gametophyte stage.
• Angiosperms are classified based on the
length of their life cycles: annuals, biennials,
and perennials.
Life Cycle
• Sporophyte Stage
– Zygote develops into a sporophyte
– Produces spores or seeds that turn into
gametophytes
• Gametophyte Stage
– Produce sperm & eggs cells and need water
for sperm to swim toward the eggs
– Fertilization creates a zygote
How plants reproduce (206)
• All plants undergo sexual reproduction that
involves fertilization.
• Many plants can undergo asexual
reproduction by growing new plants from
roots, leaves, or stems. This does not involve
flowers, pollination, or seeds so it happens
quicker.
• Scientists can create identical plants to use
for experiments and copy plants with
favorable characteristics.
Gymnosperm Reproduction
• 1. produce male and female cones
• 2. a. male cones produce pollen that
develops into sperm
• b. female cones contain at least one ovule at
the base of each scale
– two egg cells form inside each ovule
• 3. Wind carries pollen from male cones to
female cones
4. after pollination, ovule & scale closes to seal
in pollen, fertilization occurs
5. female cones remain on the tree for the
seeds to develop but the male cones fall off
after shedding the pollen
6. Scales open when the seed matures and
wind disperses the seeds.
Only few seeds land in suitable places to grow.
Angiosperm Reproduction (210)
• Pollination
– A flower is pollinated when a grain of pollen falls on
the stigma.
– Animals are the main source of pollination process
• Fertilization
– If pollen falls on the stigma of a similar plant,
fertilization can occur.
– Sperm cells join with egg cells inside an ovule.
– The zygote begins to develop into the seed’s
embryo and the ovary develops into a fruit- the
means by which seeds are dispersed.
6.3 Vocabulary Terms
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Larva
Polyp
Medusa
Gestation period
How Animals Reproduce (213)
• ALL animals reproduce, but most
produce offspring that are different from
the parents.
• Reproduction is essential to the survival
of the species.
Asexual
• Certain organisms can form new animals
from cut pieces.
• In budding, a new animal grows out of the
parent and breaks off.
Sexual
• Sperm cells and egg cells carry DNA that
determines physical characteristics.
• Each sex cell brings DNA material from both
parents to create offspring with completely different
DNA.
• The offspring may not look exactly alike either
parent.
• Most vertebrates and invertebrates reproduce
sexually.
• Few animals produce both sex cells in the same
organism. Individuals will fertilize the eggs of
another individual, but not their own.
Compare (215)
• Asexual
– Advantage: One parent
can produce many
identical offspring
– Disadvantage: Offspring
has the exact DNA and
may not survive
environmental changes.
• Sexual
– Advantage: produce
offspring with new
combination of DNA.
They may have
characteristics may help
them adapt and survive.
– Disadvantage: requires
finding a mate and
longer time to develop
offspring.
Sponge Reproduction (216)
1. Adult sponge releases sperm
2. Sperm enter another sponge and fertilize
an egg (produces both sex cells)
3. A larva develops
4. Water currents wash the larva away
5. Larva settles on a surface and develops
into an adult.
** Sponges can also bud.
Cnidarian Reproduction (217)
1. Adult medusas release eggs and sperm
2. Fertilized eggs develop into larva
3. Larva attaches to surface and develops
into a polyp
4. Parts of the polyp break away (asexual)
5. Each polyp matures into a medusa
Internal vs. External (218)
• Fertilization may occur either outside or
inside of the female organism’s body.
• Many fish, amphibians, aquatic invertebrates
fertilize in water to prevent the eggs and
sperm from drying out.
• Male aquatic vertebrates and mammals
fertilize the egg directly in the female.
– Some lay the fertilized eggs and some give birth
to live young after a gestation period.
6.4 Vocabulary Terms
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Amniotic egg
Placenta
Metamorphosis
Pupa
Nymph
Tadpole
Developing Embryos (221)
• Growing embryos may develop outside or
inside of the parent’s body.
• If developing outside, an embryo will grow
inside an egg. The contents of the egg
provide all the nutrients it needs.
• Some embryos develop in an egg that is
retained within the parent’s body. The parent
does not provide nutrients. The egg may
hatch either before or after being released
from the parent.
Embryos
• Most mammal embryos develop inside the
mother’s body. The mother provides
everything it needs during development
through the placenta.
• Food and oxygen are passed to the
embryo but the mother’s blood does not
mix with the embryo’s blood.
Animal Development (223)
• Some young animals look like small versions
of adults, but other go through
metamorphosis.
• Crustaceans begin as tiny, swimming larvae
that develop into adults.
• Amphibians begin as fertilized eggs in water.
Tadpoles wiggle out of eggs and begin
swimming. Hind legs develop and the tail is
absorbed before becoming an adult.
Metamorphosis (224)
• Insects go through complete or incomplete
metamorphosis.
• Complete metamorphosis has four stages:
egg, larva, pupa, and adult. Major changes
occur as the pupa becomes an adult.
• Incomplete metamorphosis has three
stages: egg, nymph, and adult. As the
nymph grows, it sheds its exoskeleton
(hard outer shell) many times.
Caring for Young (227)
• Most amphibians and reptiles release eggs
into water and do not provide parental care.
Offspring must be able to care for
themselves from the time of birth.
• Most birds and mammals typically care for
their offspring. Birds feed and protect their
young while mammals feed with mother’s
milk since their young are helpless for a long
time.