BIO 123 Cal Poly Midterm 1

What is biology

study of life

What is sex

sharing of genetic material, making offspring that has genetic material from at least 1 parent

Scientific Method

1. Ask Q

2. Propose Hyp.

3. Design Study (observational v experimental)

4. Make predictions

5. Perform study, analyze study

6. Draw conclusions

Null v Normal Hyp

null is opposite

X axis

independent variable

y axis

dependent variable

Single BLind study

participants don't know if they have placebo or drug

Double BLind study

neither participants nor scientists know if participants have placebo or drug

Avg. American penis size

5.6 inches

Where in our bodies is DNA?

every cell

DNA:

sequence of base pairs (ATGC)

some sequences are genes, these code for characteristics

carries info for growth and reproduction of cells

"Master Plan" for our bodies

Gentoype

actual DNA code

phenotype

physical traits/characteristics based on genotype

DNA--> RNA-->proteins-->phenotype

DNA is a blueprint to make RNA

RNA is a blueprint to make proteins

proteins contribute to how we look, behave (phenotype)

Allele

version of a chromosome (A or a)

How many alleles does a baby get for one gene?

1 from mom, 1 from dad

Dominant v recessive alleles

A v a or AA, Aa v a

How many chromosomes do humans have in each body cell?

46, 23 from mom. 23 from dad

What are the sex cells?

x, y

How many chromosomes does each sex cell have?

23 bc you get 1 from mom, one from dad (XX female or XY male)

Meiosis

makes sperm and eggs

halves number of chromosomes

each egg/sperm is unique

Where is DNA specifically in cells?

In cells, in nucleus are chromosomes, chromosomes have genes, which make up DNA

Epigenetics

environmental factors can turn on or off certain genes

Asexual Reproduction

offspring that arise from only 1 parent and have DNA from only 1 parent

Cloning

offspring that are genetically identical to one parent

Natural Clones

Vegetative Reproduction

Reproduction by budding

Reproduction by splitting

Reproduction by fission

Parthenogenesis

offsprings produced by females with no contribution by males

Half Clone Parthenogenesis

female reabsorbs one of her polar bodies, fuses with egg, creates non cloned offspring

Full Clone Parthenogenesis

more doubling at first stage of meiosis, results in full clone of mother

Facultative Parthenogenesis

when animals who could or would otherwise reproduce sexually do so asexually (environmental, mating reasons)

Advantage of sexual reproduction

variation

Advantages of asexual reproduction

quick, don't need to find mate

Disadvantages of asexual reproduction

no variation

How to combat no variation of asexual reproduction

parthenogenesis can occur from 2 different species which makes variation

Oviparity

lay eggs

Viviparity

live births

Spawning

all happens outside of body (eggs laid, sperm deposited) -nemo

Brooding

eggs located attached to the body, in mouth, on back, etc.

Aqua Amphibians

amphibians don't have egg shells, metamorphosis occurs (tadpoles to frogs)

Amniotic Egg

helpful in transition from water to land, gives nutrients, protects baby

How does egg prevent more than one sperm from fertilizing it?

once one sperm gets into egg and begins to fertilize, protective layer that is created spreads over egg and clears out excess sperm

Human Life Cycle

sperm and egg fertilize, cleavage (egg begins to split), blastula (mad cell division), gastrula (alignment of baby in cellular form), 1-3 trimesters, baby

Marsupials v Placental Animals

marsupials give birth very early, baby grows outside of mom

Placental babies born when fully developed

Finding a mate: How genitals help

barnacles have longest penis to body ration (20 sizes their body)

squids eject sperm in sperm sacs that open in female

octopus: 1/8 legs is penis, goes into female's mantle

argonaut has detachable penis

spiders eject needle like penis into female

Evolved Female Genitalia

ducks' corkscrew vagina with trap areas

hyena's pseudopenis

Hermaphrodites

slugs, race to see who can fertilize the other faster, then penis either falls or is nibbled off

Genitals that clean out sperm

Dragonflies

Cats

spiky penises that clear out other sperm and/or injure female so she cannot mate again

Multiple penises

echidna has 4 penis heads to help compete with other males when trying to impregnate female

Human penis

lost spikes in evolution that allows us to have bigger brain, came with smoother penis

Bacteria variaton

all different types- shape, size, mobility

Bacterial Reproduction

get new genes from dead bacteria, or through direct transfer (conjugation)

Conjugation

two bacteria allign, bridge is created and genetic material from donor is passed to recipient

no child at the end, no sex cells

How Bacteria Resist Antibiotics

Mutation occurs, antibiotics kill all non mutated cells, mutated cells reproduce, are antibiotic resistant

MRSA

staph infection is antibiotic resistant, lots of deaths per year bc of this

Sexual Reproduction in Plants

asexual and sexual

Asexual reproduction in plants

runners

corms

plantlets

some plants can self polinate

Perfect v Imperfect Flowers

perfect flowers have male and female parts on same flower,

imperfect ones (monecious or diecious) dont

Monoecious

same plant has female flower and male flowers

Diecious

female plants and male plants (weed)

Pollination

sexual reproduction of plants

Who Pollinates

birds, bees, bats, rodents, wind, water, insects

Honeybees

responsible for pollinating over $15 billion of crops/year

pesticides are killing them

Fruit

ovary develops into fruit

presence of seed = fruit

Vegetables

any part of the plant that is not the fruit

Seeds

Embryonic plant produced by fruit

dispersed by animals, wind, water