Inheritance and Selection

WALT• Offspring are similar but not identical

to their parents.• Some characteristics are inherited• These variations occur in both plants

and animals• Understand that cells have nuclei

which contain information that is inherited.

• Understand why offspring are genetically unique from their parents.

• Identify sperm and egg cells

Homework•Read 4-7•Answer questions from p. 4-5

We are all Different

•All living things are unique• We all have different characteristics.

•Some of these characteristics are inherited some are not. Nature versus nurture.

DiscussionDiscuss the following with your

table partner:- List the different types of List the different types of

characteristics humans have.characteristics humans have.- Which of these Which of these

characteristics are inherited characteristics are inherited from parents and which are from parents and which are gained in ones life time?gained in ones life time?

- Record this in your notebooks

We are Family

How can you tell they are from the same family?

We are all Different

•Characteristics of all living organisms are coded on their DNA as genes:– hair color– eye color– flower color– Height

Fertilization•Each parent contributes a sex cell called a gamete.

•Their genetic material combines to form a full set of DNA.

•You are a cross between both your parents.

All living things reproduce.

Humans use sexual reproduction to produce their young. How do plants reproduce?

In order to do this, the two parents (male and female) have different reproductive systems and organs that produce different sex cells.

Human reproduction

In males, the sex cells are called sperm.

They are produced in sex organs called testes

How are sperm specialized for their role?

Sex cells – sperm

In females, the sex cells are called eggs.

Eggs are produced in sex organs called ovaries.

Sex cells – egg

An egg is so big that this is how small a sperm looks next to it.

nucleus containing chromosomes

jelly coat

cytoplasm

membrane

GametesA full set of human chromosomes contains 23 chromosome pairs

These pairs split up in the formation of gametes

They are formed by cell division called meiosis

Gametes

Gametes

•Gametes contain half the chromosomes of a normal cell. Why?

Fertilization• Fertilization of

two gametes forms a fertilized egg, zygote.

• Gametes are formed in the …

DiscussionWith your table partner answer

the following in your notebooks:•Why are brothers and sisters Why are brothers and sisters

similar?similar? •How are identical twins formed?How are identical twins formed? •Why are identical twins more Why are identical twins more

similar than brothers and similar than brothers and sisters?sisters?

•Can identical twins be different Can identical twins be different sexes?sexes?

FertilizationIdentical twins come from the same zygote and therefore are genetically identical.

Fraternal twins come from different zygotes. What can you say about there genetic similarity?

Fertilization in Plants

•The reproductive structures of plants are ______

•Sperm (nucleus) of plants is contained inside of the ______

•The egg is contained inside of the ______

flowers

ovule

pollen

•The transfer of pollen from the anthers to the stigma is called ________

•The nucleus of pollen moves down the pollen tube and _______ the egg.

pollination

fertilizes

Flowers

Fertilization in Plants

•The resulting embryo is contained in the _____

•Plant breeders can select characteristics of offspring through ______ ________

seed

selective breeding

WALT: Species & Varieties

•Understand selective breeding•Identify and describe new breeds of animals•Understand that different breeds of animals are suited to different environments.•Understand the roll of selective breeding in plants•Suggest how selective breeding could occur

Homework: Read pp 6-11, do questions on pp. 8-11

Different, but the same

•Animals are grouped by species, that they cannot breed across (generally!)

•Species: a group of similar organisms that can produce offspring which can also be able to reproduce.

What About Wolves? Different Species or Not?

There are 4 recognized species of wolves in the world, but all can interbreed. What are they then?

Different, but the same

•Varieties are groups of organisms that are very similar in appearance, but yet are unique from other groups within the same species.

Different, but the same

•Variation can occur due to the environment.

•Name some environmental factors that affect plants.

•Due to these differences, and genetic isolation, we can get unique varieties of plants and animals.

Different, but the same

•Varieties can be created by human effort through selective breeding.

•Isaac the first recorded selective breeder…

Different, but the same

He continued, “Name me your wages, and I will give it.” 29     But he said to him, “You yourself know how I have

served you and how your cattle have fared with me. 30     “For you had little before I came and it has

increased to a multitude, and the Lord has blessed you wherever I turned. But now, when shall I provide for my own household also?”

31     So he said, “What shall I give you?” And Jacob said, “You shall not give me anything. If you will do this one thing for me, I will again pasture and keep your flock:

32     let me pass through your entire flock today, removing from there every speckled and spotted sheep and every black one among the lambs and the spotted and speckled among the goats; and such shall be my wages.

Different, but the same

33     “So my honesty will answer for me later, when you come concerning my wages. Every one that is not speckled and spotted among the goats and black among the lambs, if found with me, will be considered stolen.”

34     Laban said, “Good, let it be according to your word.”

35     So he removed on that day the striped and spotted male goats and all the speckled and spotted female goats, every one with white in it, and all the black ones among the sheep, and gave them into the care of his sons.

36     And he put a distance of three days’ journey between himself and Jacob, and Jacob fed the rest of Laban’s flocks.

Different, but the same

37     Then Jacob took fresh rods of poplar and almond and plane trees, and peeled white stripes in them, exposing the white which was in the rods.

38     He set the rods which he had peeled in front of the flocks in the gutters, even in the watering troughs, where the flocks came to drink; and they mated when they came to drink.

39     So the flocks mated by the rods, and the flocks brought forth striped, speckled, and spotted.

(Ge 30:28-39, NAS)

Different, but the same

•A special type of selective breeding is cross-breeding. – Crosses 2 different varieties or breeds together. What is the advantage of this?

– In plants we call these hybrids.

Cross-Pollination• Breeder removes

the anthers on the flower he has selected.

• Using a swab or brush a breeder takes pollen from the anther of one plant and places it on the stigma of another.

• A sack is placed over the pollinated flower. Why?

Domestication and BreedsBreeds are selected for certain

features that are desirable to the owners.

– for food production• cows and goats for meat and milk• chickens for meat and eggs

– for work• dogs, oxen, horses

– for show– for fabrics

•Sheep, angora rabbits

Domestication and Breeds

Angus

Domestication and Breeds

Holstein

Domestication and Breeds

Beefalo

Domestication and Breeds

Changes in farming lead to changes in the kind of breeds used.

– subsistence farming– commercial farming

Partner Discussion: Domestication and

Breeds• Due to the shift towards commercial farming air loom varieties are being lost. Why is this bad?• What are some problems with strict control of breeding where only a few traits are selected for?

WALT: Cloning • In cloning all genetic information comes from one parent.

•Consider ethical issues associated with cloning

Homework: do questions on pp. 12-13

Cloning•In the 1990’s we entered new age of science as we unlocked important secrets of the cell.

•Bioengineering•Cloning: is making an exact copy of an organism. This is an example of asexual reproduction.

Cloning•Dolly was the first mammal to be cloned.

Cloning•How did they do it?

Cloning•How did they do it?

1. Remove the nucleus of an egg

2. Take the nucleus from an adult animal

3. Insert it into the egg cell

4. Egg acts as if it was a zygote and turns into a baby.

Cloning•Plants are much easier to clone!

1. Take a stem cutting and put it into a culture jar

2. The stem grows new leaves and roots

Cloning

Cloning• Use of cuttings and grafting has been done for many years in horticulture.

• Many plants naturally clone themselves.

Partner Discussion: Cloning

If you could ask 5 questions to a scientist who works with cloning what would these questions be?

CloningWhat are some ethical issues related to cloning?

Write these in your notebook