Plant and Animal Plant and Animal Life CyclesLife CyclesChapter 6Chapter 677thth grade 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

• 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– 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• Sporophyte• Gametophyte• Annual• Biennial• Perennial

• 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 occurs5. female cones remain on the tree for the seeds to develop but the male cones fall off after shedding the pollen6. 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

• 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 sperm2. Sperm enter another sponge and fertilize

an egg (produces both sex cells)3. A larva develops4. Water currents wash the larva away5. Larva settles on a surface and develops

into an adult.** Sponges can also bud.

Cnidarian Reproduction (217)

1. Adult medusas release eggs and sperm2. Fertilized eggs develop into larva3. Larva attaches to surface and develops

into a polyp4. 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

• 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.