Sunken Lesson Animal Growth and
Heredity
Sunken Lesson Animal Growth and
HeredityGrade 5Grade 5
How Organisms GrowHow Organisms Grow
• Nearly all body cells produce exact copies of themselves.
• Producing identical cells allows organisms to function properly and grow.
• Nearly all body cells produce exact copies of themselves.
• Producing identical cells allows organisms to function properly and grow.
Cell DivisionCell Division
• The nucleus controls everything a cell does and tells it when to divide.
• Cell division is called mitosis.
• During mitosis a cell makes exact copies of itself.
• The nucleus controls everything a cell does and tells it when to divide.
• Cell division is called mitosis.
• During mitosis a cell makes exact copies of itself.
MitosisMitosis
• To prepare itself for mitosis, a cell makes an exact copy of its chromosomes
• During mitosis, the chromosomes pull apart, and the cell membrane pinches in at the middle
• Two new cells are formed that are identical to the parent cell
• To prepare itself for mitosis, a cell makes an exact copy of its chromosomes
• During mitosis, the chromosomes pull apart, and the cell membrane pinches in at the middle
• Two new cells are formed that are identical to the parent cell
RegenerationRegeneration
• Regeneration is a kind of healing, or tissue replacement
• When our skin is damaged, we heal through regeneration of new skin cells
• Some plants and animals can regenerate major body parts – lizards can grow new tails and starfish can grow new arms
• Regeneration is a kind of healing, or tissue replacement
• When our skin is damaged, we heal through regeneration of new skin cells
• Some plants and animals can regenerate major body parts – lizards can grow new tails and starfish can grow new arms
Asexual ReproductionAsexual Reproduction
• Many primitive organisms such as one celled bacteria reproduce by simple cell division
• Only one parent is required for asexual reproduction
• Yeast reproduce by budding – a new bud forms on the parent cell, grows, and then separates to form a new cell
• Many primitive organisms such as one celled bacteria reproduce by simple cell division
• Only one parent is required for asexual reproduction
• Yeast reproduce by budding – a new bud forms on the parent cell, grows, and then separates to form a new cell
Sexual ReproductionSexual Reproduction• Most organisms require two parents
to reproduce• Parent cells go through meiosis to
copy its chromosomes and divide• Then they go through a second stage
of division where they split their chromosomes in half.
• Gametes are formed with half the chromosomes of the parent cells
• Two gametes join to form a one new cell
• Most organisms require two parents to reproduce
• Parent cells go through meiosis to copy its chromosomes and divide
• Then they go through a second stage of division where they split their chromosomes in half.
• Gametes are formed with half the chromosomes of the parent cells
• Two gametes join to form a one new cell
Life CyclesLife Cycles
• Most organisms grow and mature through several distinct stages of life
• These stages of life are called life cycles
• All life cycles start with a young organism
• Most organisms grow and mature through several distinct stages of life
• These stages of life are called life cycles
• All life cycles start with a young organism
Direct DevelopmentDirect Development
• In direct development, the young organisms are identical to the adult organism except for size
• The young grow larger, but keep the same body features, such as shape, all their lives
• In direct development, the young organisms are identical to the adult organism except for size
• The young grow larger, but keep the same body features, such as shape, all their lives
MetamorphosisMetamorphosis
• Some organisms change greatly from the time that they are young to the time that they are adults.
• The changes in the shape or characteristics of an organisms body as it grows and matures are called metamorphosis
• Some organisms change greatly from the time that they are young to the time that they are adults.
• The changes in the shape or characteristics of an organisms body as it grows and matures are called metamorphosis
Complete metamorphosis
Complete metamorphosis
• Complete metamorphosis has four stages: egg, larva, pupa, adult
• Complete metamorphosis has four stages: egg, larva, pupa, adult
Incomplete metamorphosis
Incomplete metamorphosis
• Incomplete metamorphosis has three stages: egg, nymph, adult
• Incomplete metamorphosis has three stages: egg, nymph, adult
Inherited TraitsInherited Traits
• Many characteristics of an organism are passed from parent to offspring
• Hair or fur color, eye color, attached or free earlobes, short or long eyelashes, tongue rolling, and dominant thumbs are examples of traits that are inherited
• Traits can be dominant, or strong and seen, while others are recessive, or weak and hidden
• Many characteristics of an organism are passed from parent to offspring
• Hair or fur color, eye color, attached or free earlobes, short or long eyelashes, tongue rolling, and dominant thumbs are examples of traits that are inherited
• Traits can be dominant, or strong and seen, while others are recessive, or weak and hidden
GenesGenes• Genes are structures on
chromosomes that are found in a cell’s nucleus
• Genes contain the code for the traits that an organism gets from its parents
• Genes are structures on chromosomes that are found in a cell’s nucleus
• Genes contain the code for the traits that an organism gets from its parents
Recessive TraitsRecessive Traits
• If a recessive trait (such as light brown fur in a rabbit or blue eyes in a human) is seen, then the organism MUST have TWO genes for that trait.
• That means that they received the recessive gene from both parents
• If a recessive trait (such as light brown fur in a rabbit or blue eyes in a human) is seen, then the organism MUST have TWO genes for that trait.
• That means that they received the recessive gene from both parents
Dominant TraitsDominant Traits
• If a dominant trait (such as dark fur or brown eyes) is seen, then the organism only needs one gene for that trait.
• That means they only had to receive the dominant gene from one parent
• If a dominant trait (such as dark fur or brown eyes) is seen, then the organism only needs one gene for that trait.
• That means they only had to receive the dominant gene from one parent