Chapter 2Chapter 2Parents & Parents & OffspringOffspringLesson 1:Lesson 1: ReproductionReproduction

Lesson 4:Lesson 4: Traits and HeredityTraits and Heredity

I CAN…I CAN…

Explain sexual and asexual Explain sexual and asexual reproduction.reproduction.

Compare and contrast sexual Compare and contrast sexual and asexual reproduction.and asexual reproduction.

Focus Question:Focus Question:

Where do living things Where do living things come from?come from?

Key VocabularyKey Vocabulary

Sexual reproductionSexual reproduction – the production of a – the production of a new organism from two parents.new organism from two parents.

FertilizationFertilization – the joining of an egg cell – the joining of an egg cell and a sperm cell to form a new offspring.and a sperm cell to form a new offspring.

Asexual reproductionAsexual reproduction – the production of – the production of a new organism from a single parent.a new organism from a single parent.

Key VocabularyKey Vocabulary

Vegetative PropagationVegetative Propagation – asexual – asexual reproduction in plants that produce new reproduction in plants that produce new plants from leaves, roots, or stems.plants from leaves, roots, or stems.

RunnersRunners – plant stems that lie on or – plant stems that lie on or under the ground and sprout up as new under the ground and sprout up as new plants.plants.

Where do living things Where do living things come from?come from?

Living things come from OTHER LIVING Living things come from OTHER LIVING THINGS.THINGS.

The survival of a species depends on its The survival of a species depends on its ability to produce new members.ability to produce new members.

Every organism comes from a parent Every organism comes from a parent organism through the process of organism through the process of reproduction.reproduction.

ReproductionReproduction

Reproduction involves the transfer of Reproduction involves the transfer of genetic material from parent to offspring.genetic material from parent to offspring.

The genetic material contains information The genetic material contains information that controls how the new individual will that controls how the new individual will look and function.look and function.

There are two main types of There are two main types of reproduction: sexual & asexualreproduction: sexual & asexual

Sexual ReproductionSexual Reproduction

A sperm cell from a male and an egg cell A sperm cell from a male and an egg cell from a female join in a process called from a female join in a process called fertilization.fertilization.

The fertilized egg cell contains genetic The fertilized egg cell contains genetic material from both parents.material from both parents.

The fertilized egg goes on to develop into The fertilized egg goes on to develop into a new individual who will have some a new individual who will have some characteristics, or traits from each parent.characteristics, or traits from each parent.

TraitsTraits

A trait is a characteristics of a living thing.A trait is a characteristics of a living thing. What are some traits that we can name?What are some traits that we can name?

Asexual ReproductionAsexual Reproduction

Produces a new offspring that has the Produces a new offspring that has the same genetic information as the parent.same genetic information as the parent.

No female or male sex cells combine No female or male sex cells combine during this process.during this process.

Since there is only one parent, genetic Since there is only one parent, genetic information is not mixed and the offspring information is not mixed and the offspring is identical to the original parent.is identical to the original parent.

Asexual ReproductionAsexual Reproduction

There are organisms that reproduce asexually There are organisms that reproduce asexually in all six kingdoms.in all six kingdoms.

All members of the bacteria kingdom and most All members of the bacteria kingdom and most protists replace asexually.protists replace asexually.

Most fungi and many plants can reproduce like Most fungi and many plants can reproduce like this.this.

Animals such as jellyfish, corals, worms, and Animals such as jellyfish, corals, worms, and some echinoderms as well as some kings of some echinoderms as well as some kings of lizards, frogs, fish, and insects can form lizards, frogs, fish, and insects can form offspring asexually.offspring asexually.

Methods of Methods of Asexual ReproductionAsexual Reproduction

Splitting Splitting – the organism makes a copy – the organism makes a copy of its own genetic material and then splits of its own genetic material and then splits into two cells.into two cells.

BuddingBudding – a small part of the parent’s – a small part of the parent’s body grows into a tiny and complete body grows into a tiny and complete version of the parent and then breaks off version of the parent and then breaks off and continues to grow.and continues to grow.

Other Methods of Other Methods of Asexual ReproductionAsexual Reproduction

Sometimes female eggs just develop into a new Sometimes female eggs just develop into a new animal without fertilization.animal without fertilization.

Example: Queen honeybeeExample: Queen honeybee

Vegetative PropagationVegetative Propagation – produces new plants – produces new plants from leaves, roots, or stems.from leaves, roots, or stems.

Runners are plant stems that lie on or under the Runners are plant stems that lie on or under the ground and sprout up as new plants.ground and sprout up as new plants.

Example:Example: strawberry plants, grasses, aspen trees, fernsstrawberry plants, grasses, aspen trees, ferns

How do sexual and asexual How do sexual and asexual reproduction compare?reproduction compare?

Asexual reproduction is convenient Asexual reproduction is convenient because the parent does not have to rely because the parent does not have to rely on another organism.on another organism.

Sexual reproduction promotes variety in Sexual reproduction promotes variety in a species that can better adapt to a a species that can better adapt to a changing environment.changing environment.

I CAN…I CAN…

Describe how traits are Describe how traits are passed from one generation passed from one generation to the next.to the next.

Explain dominant and Explain dominant and recessive traits.recessive traits.

Focus QuestionFocus Question

How are traits passed How are traits passed from one generation from one generation

to the next?to the next?

Key VocabularyKey Vocabulary

HeredityHeredity – the passing down of traits from – the passing down of traits from parents to offspring.parents to offspring.

Inherited traitInherited trait – a trait that an offspring receives – a trait that an offspring receives from its parents.from its parents.

InstinctInstinct – a way of acting or behaving that an – a way of acting or behaving that an animal is born with and does not have to learn.animal is born with and does not have to learn.

Key VocabularyKey Vocabulary

GeneGene – contains chemical instructions for – contains chemical instructions for inherited traits.inherited traits.

Dominant traitDominant trait – one that dominates, or – one that dominates, or masks, another form of that trait.masks, another form of that trait.

Recessive traitRecessive trait – one that is hidden, or – one that is hidden, or masked, by another form of the trait.masked, by another form of the trait.

Key VocabularyKey Vocabulary

PedigreePedigree – a chart used to trace the – a chart used to trace the history of traits in a family.history of traits in a family.

CarrierCarrier - any individual who has inherited - any individual who has inherited the gene for a trait, but does not show the gene for a trait, but does not show that trait physically.that trait physically.

HeredityHeredity What causes us to look the way we look?What causes us to look the way we look? Heredity applies to all organisms.Heredity applies to all organisms. In plants, flower color and plant height are In plants, flower color and plant height are

inherited traits.inherited traits. Inherited trait is a trait that an offspring Inherited trait is a trait that an offspring

receives from its parents.receives from its parents. Some inherited traits in humans include Some inherited traits in humans include

dimples, hair and eye color, facial features, dimples, hair and eye color, facial features, and even the way you laugh.and even the way you laugh.

Can heredity affect Can heredity affect behavior?behavior?

Some behaviors, such as instincts, are Some behaviors, such as instincts, are inherited.inherited.

An instinct is a way of acting or behaving that An instinct is a way of acting or behaving that an animal is born with and does not need to an animal is born with and does not need to learn.learn.

A learned behavior is developed during the A learned behavior is developed during the course of a lifetime.course of a lifetime.

Learning results from practice and experience.Learning results from practice and experience. The ability to learn helps animals to survive.The ability to learn helps animals to survive.

How are traits inherited?How are traits inherited?

What controls the traits you inherit?What controls the traits you inherit? Why do some people look more like one Why do some people look more like one

parent than another?parent than another? Gregor Mendel answered a lot of these Gregor Mendel answered a lot of these

questions.questions. He was an Austrian monk who studied He was an Austrian monk who studied

and discovered the basic principles of and discovered the basic principles of heredity.heredity.

Inheridited TraitsInheridited Traits After years of experimenting, Mendel determined After years of experimenting, Mendel determined

that inherited traits are passed from parents to that inherited traits are passed from parents to offspring through reproduction.offspring through reproduction.

He believed that each inherited trait is controlled by He believed that each inherited trait is controlled by two factors – the offspring receive one of these two factors – the offspring receive one of these factors from each parent.factors from each parent.

These are called genes.These are called genes. A gene is a chemical instruction for inherited traits.A gene is a chemical instruction for inherited traits. They are stored on cell structures called They are stored on cell structures called

chromosomes, which are found in the nucleus of the chromosomes, which are found in the nucleus of the cell.cell.

Who picks the traits we Who picks the traits we get?get?

Mendel concluded that for every trait Mendel concluded that for every trait there is a dominant form and a recessive there is a dominant form and a recessive trait.trait.

Each form of the trait can be represented Each form of the trait can be represented by a letter.by a letter. Capital letters = Dominant traitsCapital letters = Dominant traits Lowercase letters = Recessive traits.Lowercase letters = Recessive traits.

Dominant vs. RecessiveDominant vs. Recessive

Mendel’s findings are important because Mendel’s findings are important because they apply to all organisms.they apply to all organisms.

In humans, genes that determine the In humans, genes that determine the shapes of your earlobes, hairlines, and shapes of your earlobes, hairlines, and thumbs all have dominant and recessive thumbs all have dominant and recessive forms.forms.

Dominant traits tend to be expressed Dominant traits tend to be expressed more frequently than recessive traits.more frequently than recessive traits.

How do we trace How do we trace inherited traits?inherited traits?

Some of the traits controlled genes are Some of the traits controlled genes are easy to see, like hair color.easy to see, like hair color.

Genes also control many things you Genes also control many things you cannot see.cannot see.

Some individuals carry a trait without Some individuals carry a trait without showing evidence of that trait.showing evidence of that trait.

You can find out who carries what trait by You can find out who carries what trait by using a pedigree. using a pedigree.

PedigreePedigree A pedigree is a chart used to trace the history of A pedigree is a chart used to trace the history of

traits in a family and are used to study heredity traits in a family and are used to study heredity patterns.patterns.

Parents and offspring are shown in a pedigree.Parents and offspring are shown in a pedigree. Horizontal lines connect parents and vertical lines Horizontal lines connect parents and vertical lines

connect parents to offspring. Males are connect parents to offspring. Males are represented as boxes and females are shown as represented as boxes and females are shown as circles.circles.

Individuals with a dominate trait are shaded and Individuals with a dominate trait are shaded and unshaded shapes represent recessive individuals.unshaded shapes represent recessive individuals.