Variation & Evolution

Question 1

Define variation

Answer 1

the differences in characteristics of individuals in a population

Question 2

process of selectige breeding

Answer 2

1. choose parents with desired characteristic from mixed population
2. breed them together
3. choose offspring with desired characteristics and breed them
4. continue over many generations until all offspring now show the desired characteristic

Question 3

define evolution

Answer 3

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

Question 4

give 4 examples where selective breeding is used

Answer 4

1. disease resistance in crops
2. animals that produce more meat/milk
3. domestic dogs with a gentle nature
4. larger or unusual flowers

Question 5

give 2 disadvantages of selective breeding

Answer 5

1. can lead to inbreeding where some breeds are particularly prone to inherited defects or diseases
2. reduces variation, meaning all of a species could be susceptible to certain diseases

Question 6

define a clone

Answer 6

a clone is an individual that has been produced asexually and is genetically identical to its parent

Question 7

define genetic engineering

Answer 7

a process that involves changung the genome of an organism by introducung a gene from another organism to produce a desired characteristics

Question 8

give 2 examples

Answer 8

-bacterial cells have been genetically engineered to produce useful substances such as human insulin to treat diabetes

2. plant crops have been genetically engineered to be resistant to diseases, insects, or herbicides, or to produce bugger/better fruuts and hugher yields
   -produces genetically modified crops

Question 9

process of genetic engineering

Answer 9

1. identify gene that you want to to transfer
2. transfer gene into small section of dna called a plasmid (could use a virus)-both called vectors
3. desired gene is transferred to cells of the organism

Question 10

what is the only time u can transfer the gene into the organism

Answer 10

at early stages of development

Question 11

benefits of genetic engineering

Answer 11

-potential to overcome some inherited human diseases
-can lead to higher value of crops as gm crops have bigger yields than normal
-crops can be engineered to be resistant to herbicides/make their pwn pesticides/be more resistant to environmental conditions

Question 12

method of animal cloning by embryo transplants

Answer 12

-use sperm and egg cell from organisms that have characteristic we eant
2. fertilisation + allow to develop into early stage embryo (must not have began to specialise)
3. split into 2
3. transplant into host organism mothers
-they give birth to clones
-embryos will grow and develop
4. born as 2 identical offspring

Question 13

problem with embryonic transplants

Answer 13

because we start off with sperm and egg, we cannot be certain we will get the characteristics which we want

Question 14

describe stages of adult cell cloning

Answer 14

1. remove cell from animal you want to clone (eg skin)
2. remove nucleus from this cell
3. take unfertilised egg cell from same species
4. remove and throw away nucleus from unfertilised egg
   5.insert nucleus from original adult body cell into empty egg cell
5. give egg cell electric shock to make it form an embryo
   7.when it has developed into ball of cells, it is inserted into womb of adult host mother
   -host mother gives birth to clones

Question 15

how did darwin propose theory of evolution

Answer 15

after gathering evidence from a round the world expedition, experimentation and discussion

Question 16

what does darwin’s theory of evolution state

Answer 16

that all living species evolved from a common acestor that fist developed more than three billion years ago

Question 17

why was darwin’s theory not originally accepted

Answer 17

because it challenged the theory that god created all the living prganisms on earth

people believed there was not enough evidence

nobody understood how genetics were inherited

Question 18

what did john lamarck suggest

Answer 18

that when a characteristic is regularly used, it becomes more developed, this strengthened characteristic is then passed onto the offspring

Question 19

problem with lamarck’s theory

Answer 19

changes that occur in an animal’s lifetime cannot be passed onto offspring

Question 20

describe process of speciation

Answer 20

1. two populations of one species are isolated
2. natural selection occurs so that the better adapted individuals reproduce and pass on these different characteristics
3. the populations have an increasing number of genetic mutations as they adsot to their different environment
4. eventualky the two populations are so gentically different they cannot breed to peoduce fertile offspring

Question 21

what are the 3 main evidences for evolution

Answer 21

1. fossil records
2. has been shown that characteristcs are passed onto to the offspring in genes
3. the evolution of antibiotic resistance in bacteria

Question 22

what did mendel create

Answer 22

the idea of genes (dominant and recessive alleles)

Question 23

why was mendel’s work not significant until after his death

Answer 23

-most scientists believed in a blended inheritance

-he published his work in an obscure journalso not many people saw it

-he was a monk and not a scientist

Question 24

give 3 stages in the development of gene theory

Answer 24

1. in late 29th century, behaviour of chromosomes during cell division was observed
2. in early 20th century, genes and chromos9mes were observed to behave similarly, leading to the idea that genes were located on chromosomes
3. mid 20th century, wtructure of dna and mechanism of gene function were determined

Question 25

define fossils

Answer 25

the remains or organisms from millions of years ago found in rocks

Question 26

name 3 ways fossils form fossils can be formed from..

Answer 26

1. parts of an organism that do not decay because one or more of the conditions needed for decay are absent (not enough oxygen and water) 2. hard parts of organism when replaced by minerals 3. preservation of the traces pf organisms (burrows, footprints, rootlet traces)

Question 27

problems with fossils

Answer 27

-many early forms of life were soft-bodied organisms -there are gaos in the fossil record as not all fossils have been found and others have been destroyed by geological or human activity

Question 28

benefits of fossil records

Answer 28

-can tell scientists hwo individual species have changed over time -fossils allow us to understand how life developed over earth’s history -fossils can be used to trafk the movement od a species or its ancestors across the world

Question 29

how can we reduce rise of antibiotic resistant strains

Answer 29

1. doctors should only prescribe antibiotics for serious bacterial infections 2. patients should complete their courses of antibiotics so all bacteria are killed and mone surgige to form resistant bacteria 3. the use of antibiotics in farming and agriculture should be restricted

Question 30

describe process or antibiotic resitant bacteria

Answer 30

1. mutation makes an antibiotic resistant bacterium 2. antibiotic kills all bacteria but the one which is immune to the antibiotic 3. resistant bacteria grow and reproduce 4. all bacteria are now resistant

Question 31

mneumonic for class system thing

Answer 31

KPCOFGS king penis cums only for good sex kingdom, phylum , class, order, family, genus, species

Question 32

3 domain system

Answer 32

-archae -bacteria -eukaryota

Question 33

what are organisms named by

Answer 33

binomial system (genus, species)

Question 34

evoluntionary trees

Answer 34

use current classification data for living organisms and fossil data for extinct organisms to show how scientists believe organisms are related