1. Reproduction, Heredity, and Genetics

2. Living Organisms Some basic characteristics of life:
Need
H2O
Need
NUTRIENTS
GAS
EXCHANGE
Made of
CELLS
REPRODUCE

3. Living Organisms Some basic characteristics of life:
All living things
need
H2O

4. Living Organisms Some basic characteristics of life:
Living things Need
NUTRIENTS

5. Living Organisms Some basic characteristics of life:
Living things have
a system for
GAS
EXCHANGE

6. Living Organisms Some basic characteristics of life:
Made of
CELLS
Multicellular
Unicellular

7. Living Organisms Some basic characteristics of life:
All living things
REPRODUCE
ASEXUALLY
to create new individuals
that are clones
SEXUALLY
to create new individuals
with a combination of traits

8. ASEXUAL REPRODUCTION Only one parent reproduces.
The same genetic material (DNA) is passed directly from parent to offspring.
All offspring are CLONES of the parent and have the exact same traits.

9. Types of Asexual Reproduction
Fission
Cell division by a parent cell splitting into two parts, each growing into a new exact copy of the parent cell.
Budding
To develop as a growth on a parent, then break off and mature into a new exact copy of the parent.
Fragmentation and Regeneration
Offspring can grow from a fragment (piece) of the parent, or the parent can re-generate the missing piece.

10. FISSION

11. FISSION

12. BUDDING

13. Planarians are flat worms that can be rapidly regenerate.
Fragmentation
They can be cut
across or along
their body.

14. Regeneration

17. SEXUAL REPRODUCTION Two parents (of opposite sex) reproduce.
Two sex cells (one from each parent) combine during fertilization.
Parents combine genetic material (DNA) to form offspring that has a COMBINATION of parent’s traits.
Sperm
23 x
Egg
23 X
zygote
46 X

18. Female cell divides to produce eggs Male cell divides to produce sperm
Contains half
of the
father’s DNA
Contains half
of the
mother’s DNA
Mothers half
+ fathers half
= Full set of DNA

19. Genes and Chromosomes

20. GENES and CHROMOSOMES Inside the cell nucleus are chromosomes.
Chromosomes are bundles of tightly coiled strands of long molecules called DNA.
A segment of DNA codes for a trait.
These segments are called GENES.

21. A gene codes
for a specific
type of trait.
Each trait is
determined by
a pair of
GENES.

22. A chromosome is a bundle of DNA. Segments of DNA are genes.

23. Gregor Mendel -Austrian Monk -Gardener/Scientist -Worked with peas
-Noticed patterns of
traits in generations
-Developed the main
idea of heredity

24. Gregor Mendel determined that…
Each trait is determined by a pair of genes
– one from each parent.
Both parents contribute equally to your genes.
A gene is either dominant or recessive.
Three possible gene pairs for any trait:
2 dominant genes
2 recessive genes
1 dom and 1 rec gene

25. Dominant Genes
Dominant genes are ‘stronger’ than recessive genes, and can cover them up.
If at least one gene in the gene pair is dominant, then the individual will ‘express’ the dominant form of the trait.
Represented with a CAPITAL letter… Usually the first letter of the trait.
Ex: Black fur is dominant, so
B = a dominant gene.

26. Recessive Genes
Recessive genes are weaker, and cannot cover up dominant genes.
ONLY if both genes in the gene pair are recessive, then the individual will ‘express’ the recessive form of the trait.
Represented with a lower case letter.. Usually the first letter of the trait.
Ex: Black fur is dominant, white fur is recessive, so b = a recessive gene.

27. Genotypes and Phenotypes
Possible gene combinations
Genotype
Phenotype
2 dominant genes AA
Purebred dominant
Dominant trait expressed
1 dominant gene and recessive gene Aa
Hybrid
2 recessive genes aa
Purebred recessive
Recessive trait expressed

28. dominant dominant dominant
Gregor Mendel studied many traits of pea plants, like seed color and shape, and the color of the petals.
dominant

29. Traits in Humans Dominant Recessive
Brown eyes
farsightedness
normal vision
Dimples
unattached earlobes
Freckles
broad lips
Gray, blue, green, hazel
normal vision
Nearsightedness
night blindness
color blindness*
no dimples
attached earlobes
no freckles
thin lips

30. Practice Questions DIMPLES ARE DOMINANT OVER DIMPLE-LESSNESS.
What is the genotype of someone who has no dimples?
What is the phenotype of someone who has a genotype of Dd? dd
They have dimples.

31. They have straight hair.
Practice Questions
CURLY HAIR IS DOMINANT OVER STRAIT.
What is the genotype of someone who has curly hair?
What is the phenotype of someone who has a genotype of cc?
CC or Cc
They have straight hair.

32. Practice Questions Aa BB Cc dd ee FF Gg hh
Which of the gene pairs are:
Purebred dominant?
Hybrid?
Purebred recessive?