Variation and speciation

Question 1

define genetic variation and examples

Answer 1

variation caused by genes, inherited from parents (sex, blood type, eye colour)

Question 2

define environmental variation and examples

Answer 2

variation caused by environmental factors and lifestyle (tattoos, gender, bilingual)

Question 3

difference between identical and non identical twins?

Answer 3

Identical - one egg fertilised by one sperm, but egg divides in half. is random

non identical - two separate eggs fertilised by two separate sperm in same pregnancy.

Question 4

define species

Answer 4

a group of organisms which can interbreed and produce viable, fertile offspring

Question 5

what is natural selection?

Answer 5

when organisms gain an advantage, so are more likely to survive and breed

Question 6

define evolution

Answer 6

a change in the inherited characteristics of a population over time through a process of natural selection

Question 7

what are the stages of evolution?

Answer 7

• overproduction
• variation
• reproduction
• selection
• adaptation

Question 8

What was Lamarck’s theory of evolution?

Answer 8

body parts developed throughout an organisms lifetime are passed down to offspring

Question 9

what was Darwin’s theory of evolution?

Answer 9

characteristics change over time in response to environment

Question 10

what was Wallace’s theory of evolution?

Answer 10

• same as darwin but proposed mimicry

Question 11

what causes speciation?

Answer 11

geographical and reproductive isolation

Question 12

how does geographical isolation cause speciation?

Answer 12

• seperate members of same species split apart and adapt to different environments over time leading to formation of a new species

Question 13

how does reproductive isolation cause speciation?

Answer 13

• members of same species not physically separated but do not reproduce for other reason (think red horns/blue spots) leading to formation of new species

Question 14

what is classification?

Answer 14

grouping of organisms based on differences and similarities in their structure and characteristics

Question 15

refer to page 10 of biology book 3 for features of different kingdoms

Answer 15

JUST DO IT!

Question 16

what was the order of the classification system devised by Carl Linnaeus?

Answer 16

Kingdom
Phylum
Class
Order
Family
Genus
Species

Question 17

how are species named?

Answer 17

with the latin binomial system

Question 18

writing rules for binomial system

Answer 18

• written in italics and only genus starts with a capital letter
  if handwritten, underline it

Question 19

why is latin used for naming species?

Answer 19

so naming system is universal

Question 20

what did Woese do?

Answer 20

added ‘domain’ above kingdom, as he studied archaea and bacteria, and decided to separate them

Question 21

why did Woese separate bacteria and archaea?

Answer 21

• archaea’s nucleic acid was closer to eukaryotes than bacteria
• DNA was very different

Question 22

when did carl woese work in comparison to carl linnaeus

Answer 22

Woese - 1977
Linnaeus - 1778

Question 23

how to decipher evolutionary trees?

Answer 23

• base is last common ancestor
• shows change in evolution over time
• top of the tree is most recent

Question 24

what is a fossil?

Answer 24

the remains of an organism that lived millions of years ago

Question 25

why do we need fossils?

Answer 25

- to prove/disprove theories - as humans weren't there to witness it

Question 26

how does mineralisation work?

Answer 26

- organism dies and is on the ground - soft fleshy parts decay leaving hard parts like bone to remain - sediment collects on top of skeleton - bone is replaced by minerals under the pressure of sediment, forming the shape of a bone - over time sediment is eroded/dug up and discovered by humans

Question 27

how do trace fossils work?

Answer 27

- preserved traces of organisms such as footprints, burrows and rootlet traces can be buried under layers of sediment which eventually become rock

Question 28

how does amber work?

Answer 28

- whole insects or plant parts become trapped in resin/sap from a tree - this resin falls into water and is covered by sediment - is an oxygenless process

Question 29

why do pet bogs, ice and amber preserve well?

Answer 29

there is no oxygen for microoorganisms to decay soft parts

Question 30

how can age of fossil be indicated?

Answer 30

depth in sediment

Question 31

why might fossil records be incomplete?

Answer 31

- conditions must be just right for formation - geological activity can damage/destroy fossils - early life forms were soft bodied so no hard parts to be fossilised - not all fossils found yet

Question 32

what is extinction?

Answer 32

when no remaining individuals of a species are left alive

Question 33

what is a mass extinction?

Answer 33

when >75% of species go extinct

Question 34

what is the holocene extinction?

Answer 34

current extinction event with estimated 140,000 species lost per year

Question 35

how do bacteria become antibiotically resistant?

Answer 35

(Is a form of evolution by natural selection) . Non-resistant bacteria exist . They multiply by the billions by binary fission, and some mutate . Some of these mutations make the bacteria antibiotically resistant . In the presence of drugs, only resistant bacteria survive . Drug resistant bacteria multiply and thrive

Question 36

what is a selection pressure?

Answer 36

a change in environment that causes some individuals to die off and some to survive eg. new disease or drug, change in climate or resources

Question 37

what is selective breeding?

Answer 37

breeding organisms with desired characteristics.

Question 38

describe the process of selective breeding?

Answer 38

- humans select two animals with required characteristics - they are allowed to breed - when offspring is produced, individuals with the most desirable characteristics are chosen and mated again - takes place for many generations until organism with all correct characteristics is created.

Question 39

benefits and drawbacks of selective breeding?

Answer 39

benefits - increased yield - potential for survival enhancement - can be made less dangerous - gives desired characteristics drawbacks - reduced gene pool increases risk of genetic disorders or disease susceptibility - disease genes could be unknowingly selected, eg. deaf dalmations - takes long time

Question 40

what is a clone?

Answer 40

a genetically identical organism

Question 41

what are the 2 types of plant cloning?

Answer 41

- propogation - tissue culture

Question 42

describe the process of propogation

Answer 42

- choose parent plant with desired characteristics - cut small (meristematic shoot) section of plant - trim end - dip in hormone rooting powder to inc. rate of rooting - plant in moist compost/water with added nutrients - keep in moist atmosphere until roots develop to reduce transpiration loss

Question 43

describe process of tissue culture?

Answer 43

- take a few cells from plant - grow them with hormones to stimulate division - grow them in different hormones to stimulate growth into small plants

Question 44

key facts about plant tissue culture?

Answer 44

- expensive but can grow thousands of plants from small amount of tissue - guarantees plants grown have desired characteristics - intitially grown in agar, then transferred to compost once they've outgrown the petri dish - must be aseptic

Question 45

what are the two types of animal cloning?

Answer 45

1. embryo transplant/transfer 2. Adult cell cloning

Question 46

describe the process of embryo transplant

Answer 46

1. sperm taken from animal with desired characteristics 2. female artificially inseminated with sperm 3. zygotes develop into embryos in animal and are removed from uterus 4. embryos are split into several smaller ones, each can grow into a new animal 5. embryos placed in foster mothers 6. animal born

Question 47

describe the process of adult cell cloning

Answer 47

- diploid nucleus removed from animal A cell - haploid nucleus removed from animal B ovum - diploid nucleus from animal A fused with empty ovum from animal B after a mild electric shock, begins to divide, forming an embryo - cloned embryo is implanted into uterus of animal C - animal born is a clone of animal A

Question 48

what is genetic engineering?

Answer 48

- a process which involves modifying the genome of an organism by introducing a gene from another organism to give a desired characteristic

Question 49

what is recombinant DNA?

Answer 49

DNA that has been edited by swapping genes

Question 50

describe the process of genetic engineering

Answer 50

- a vector (plasmid from bacterium or a virus) is cut open using enzymes - required gene is also cut from donor organism using same enzymes - these are fused together using sticky ends, is now recombinant DNA - recombinant DNA inserted back into bacterium, which is now transgenic - transgenic bacterium checked if it has required gene by inserting genetic marker gene, eg. fluorescence - bacterium allowed to divide

Question 51

what are genetically modified crops?

Answer 51

- crops genetically modified to become herbicide resistant, insect resistant, more nutritious, larger etc.

Question 52

pros and cons of GM?

Answer 52

pros - can increase yields and nutrition - food can grow in harsher conditions - medical treatments can save lives - faster than selective breeding - decreased need for for insecticides etc. cons - can be elitist - could harm wildlife or humans - may be considered unethical, religious/moral objections - can't collect seeds - risk of allergic reactions - limited long term testing - risk of cross-pollination