component 2

Question 1

definition species

Answer 1

organisms that can interbreed to produce fertile offspring

Question 2

development of an ovule (female gamete in plant)

Answer 2

megaspore mother cell undergoes meiosis 1 AND 2.
3 cells die and one remains
this cell undergoes 3 rounds of mitosis
-3x antipodals are formed
-2x polar nuclei
2x synergids
1x female gamete

Question 3

how is a male gamete in a plant formed

Answer 3

1- mother cell divide by meiosis
2- 4 haploid cells produced (tetrad)
3-these each undergo differentiation to form pollen grains
4- these undergo mitosis BUT NOT CYTOKINESIS
5- this forms pollen with 1 tube nucleus and 1 generative nucleus

Question 4

what is discontinuous variation

Answer 4

-monogenic
-a type of variation that can be categorised
-blood group, eye colour
-NOT ENVIRONMENTAL
-HERITABLE

Question 5

what is continuous variation

Answer 5

-polygenic
-a type of variation that cannot be categorised
-height, skin colour
-ENVIRONMENTAL
-HERITABLE AND NON-HERITABLE

Question 6

definition of genetic drift

Answer 6

describes the change in allele frequency in a population by chance.
more significant in small or isolated populations

Question 7

assumptions for hardey-weinberg

Answer 7

mating is random
organisms are diploid

large population
no mutation
no immigration or emigration

Question 8

what to do with harden-weinberg

Answer 8

NEVER assume with dominant (P)
always work out p from p+q=1
-always start with q^2=….. then square root etc..

Question 9

what is allopatric speciation

Answer 9

the evolution of a new species from demes isolated in a different geographical location

Question 10

what is sympatric speciation

Answer 10

the evolution of a new species from demes sharing a geographical location

Question 11

differences in cytokinesis in animal and plant cells

Answer 11

plant cells have no centrioles
cell wall forms from inside to out in plants
cleavage furrow forms outside to in in animal cells

Question 12

what occurs during prophase

Answer 12

-chromosomes condense and become visible
-spindle fibres form from microtubules
-nuclear envelope disintegrates
-centrioles move to opposite ends of the pole

Question 13

what occurs during metaphase

Answer 13

-spindle fibres attach to centromere of chromosomes
-chromosomes line up along equator

Question 14

what occurs during anaphase

Answer 14

-spindle fibres contract and shortens
-chromatids are pulled centromere first

Question 15

what occurs during telophase

Answer 15

-nuclear envelope reforms
-chromosomes uncoil and become more visible

Question 16

what does the ep