M4, C10 Classification and Evolution Flashcards
what would scientists look at when they discover a new organism in order to group it
Physical characteristics Behaviour DNA Mating/reproductive methods Cell structure
why do we need a single system to classify organisms
allows us to identify new species
allows scientists worldwide to share research and link organisms from different countries
allows us to find evolutionary links and find a common ancestor of species
to predict characteristics
what is the order of the taxonomic groups
kingdom phylum class order family genus species
what is the taxonomic group above kingdom
domain
what are the 3 domains
bacteria
archaea
eukarya
define species
a group of organisms that are able to reproduce fertile offspring
why could an offspring be infertile when 2 different species reproduce
it has an odd number of chromosomes
what are the rules for naming organisms
called binomial nomenclature
first word - genus, first letter is capital
second word - species, all lower case
whole name in italics or underlined because it si hard to handwrite in italics
name a lion
species is leo
genus is panthera
Panthera leo
in italics or underlined
how were organisms first classified under arstotle’s theory
he thought every organism could be put into 2 kingdoms: plants and animals
what are the 5 kingdoms
prokaryotae protoctista fungi plantae animalia
what are the features of the kingdom prokaryotae
unicellular
no nucleus or other membrane bound organelles
ring of naked DNA - small ribosomes
no visible feeding mechanism - nutrients absorbed by cell wall or produced internally by photosynthesis
give examples of organisms in the kingdom prokaryotae
bacteria - E. coli
what are the features of the kingdom protoctista
mainly unicellular
has a nucleus and membrane bound organelles
some have chloroplasts
some are immobile but others move by cilia, flagella or amoeboid mechanism
give examples of protocitsta
paramecium
amoeba
what are the features of the kingdom fungi
unicellular or multi-cellular nucleus and membrane bound organelles cell wall made of chitin no chloroplasts or chlorophyll no mechanisms for locomotion most have a body made of threads of hyphae saprophytic feeders - nutrients acquired by absorption most store food as glycogen
give examples of fungi
mushrooms
moulds
yeast
what are the features of the kingdom plantae
multi-cellular
membrane bound organelles including nucleus, cellulose cell wall
all contain chlorophyll
most don’t move but some gametes move using cilia or flagella
autotrophic - nutrients acquired by photosynthesis so make their own food
store food as starch
what are the features of the kingdom animalia
multi-cellular
nucleus and membrane bound organelles (no cell walls)
no chloroplasts
move with cilia, flagella or contractile proteins sometimes in form of muscular organs
heterotrophic - nutrients acquired by ingestion
food stored as glycogen
what have been the recent changes to the classification system
Classification used to be based on observable features
Due to advances in genetics we can now study the evolutionary relationship between organisms
When organism evolve so does their DNA, and as DNA determines proteins it in turn determines characteristics
So, for characteristics to change so does DNA
give an example of how the classification system has changed in terms of haemoglobin
Haemoglobin is a protein with 4 polypeptide chains made of a fixed number of amino acids
in chimps, their haemoglobin differs by 1 amino acid
the structure of haemoglobin is very similar meaning we must have a common ancestor
what features would distinguish a 6th kingdom
ribosomal RNA (rRNA) and the cell’ membrane lipid structure Sensitivity to antibiotics
what is the 3 domain, 6 kingdom classification system
3 domains - bacteria, archaea and eukarya
6kingdoms - eubacteria, archaebacteria, protoctista, plantae, fungi and animalia
(the prokaryotae group has been split into 2)
what are the differences and similarities between archaebacteria and eubacteria
archaebacteria can be found in extreme conditions, eubacteria found in all envrionments
eubacteria contains peptidoglycan in the cell wall wheras archaebacteria don’t
both single celled prokaryotes
define phylogeny
The evolutionary relationships between organisms. The study of it is called phylogenetics.
It shows how closely related organisms are and shows the evolution of organisms over time.
what are phylogentic trees and how do you draw them
Diagram to show the evolutionary relationships between organisms.
Older species are found further down the tree, recent species nearer to the top
The closer the branches are, the more closely related the organism are.
why is phylogeny useful
The Linnaean classification system is based purely on observable features.
Phylogeny produces a continuous tree, and organisms can be placed anywhere along it, they do not have to fit into discrete groups
The Linnaean system does not tell you anything about the number of different species or level of diversity or how long the groups have been around
what were Darwin’s observations
Organisms produce more offspring than survive
There’s variation in the characteristics of members of the same species
Some of these characteristics can be passed on from one generation to the next
Individuals that are best adapted to their environment are more likely to survive
what is the evidence for evolution
palaeontology
comparative anatomy
comparative biochemistry
what did Lyell discover
fossils are evidence of animals that lived millions of years agoo
what did Hutton propose
principle of uniformitarianism
what did Wallace propose
theory of evolution by natural selection
what evidence does the fossil record provide
bacteria and simple algae are found in the oldest rocks and vertebrates are found in more modern rocks
shows evolution happened over a long time
sequence in which organisms are found matches their ecological links to each other
can study similarities in the anatomy of fossils to see how closely related organisms have evolved from the same ancestor
investigate relationships between extinct and living organisms
why is the fossil record incomplete
soft bodied organisms decompose
destroyed in earthquakes or volcanoes
undiscovered
what is comparative anatomy
study of similarities and differences in the anatomy of different living species
what is a homologous structure
a structure that appears superficially different in different organisms but has the same underlying structure
how does comparative anatomy provide evidence for evolution
vertebrate limbs are all very similar in structure but have different functions
this shows they all must have had a common ancestor
what is divergent evolution
from a common ancestor, different species have evolved
occurs when closely related organisms diversify to adapt to new habitats as a result of migration or loss of habitat
define evolution
the slow and continual change of organisms from one generation to the next
what is comparative biochemistry
the study of similarities and differences in protein and other molecules that control life processes
what are the two most common molecules used in comparative biochemistry and why
cytochrome c
ribosomal RNA
Changes to the structure don’t affect the function so natural selection wouldn’t have changed these molecules.
what is interspecific variation
Variation between members of different species.
what is intraspecific variation
Variation between members of the same species.
what causes variation
genetics
environment
or both
give an example of a human characteristic with variation caused by:
a) environment
b) genetics
c) both
a) scar
b) blood group
c) height
what causes genetic variation
alleles mutations meiosis sexual reproduction chance
how do alleles cause genetic variation
different alleles produce different effects
different combinations are formed from parents
so different organisms in a species have different alleles
how do mutations cause genetic variation
changes made to DNA sequence so proteins are changed
this affects physical and metabolic characteristics
if a mutatio occurs in gametes then it’s passed onto offspring
what are the two types of meiosis
how do they causes genetic variation
independent assortment and crossing over
gametes are produced by meiosis
each gamete receives half the genetic content of the parent cell
before nucleus divides, the genetic material mixes up
how does sexual reproduction cause genetic variation
genes are inherited from two parents and it’s random
what is discontinuous variation
how is it represented
a characteristic that can only result in certain values
there are no in-between values
normally represented using a bar chart or pie chart
what is continuous variation
a characteristic that can take any value within a range
data collected in frequency table and plotted on a histogram or graph
what are the characteristics of a normal distribution curve
the mean, median and mode are the same
it is bell-shaped which is symmetrical about the mean
50% of values are less than the mean and 50% are greater
most values lie close to the mean value
what is standard deviation
what does it mean when it is large
measure of how spread out the data is
the greater the sd, the greater the spread of data which means a higher variation
how do you work out standard deviation the long way?
work out the mean minus the mean from each value square these values add them all up divide that number by the (sample size - 1) square root
What is the Student t-test used for
Compares the mean value for two sets of data
Checks whether there’s a significant difference between the mean values or whether the difference is just down to chance
Look at the Student t test equation
What do they all stand for
Mean population 1 Mean population 2 S1 - standard deviation population 1 S2 - standard deviation population 2 N1 - total number of samples pop 1 N2 - total number of samples pop 2
What is the equation for degrees of freedom
Df = n1 + n2 - 2
How do you use a significance table
What out the degrees of freedom for the left hand side
Go along to 5%
From the significance table, what do the results tell you
If the t value is less than the stated value, then there’s no significant difference between the mean results
If the t value is greater than the stated value then there is a significant difference
What is null hypothesis
Always suggests there will be no correlation between the factors you’re investigating
We have to say whether we accept or reject null hypothesis based on results in a t test or correlation coefficient
If results aren’t statically significant it means the correlation could be down to chance
What does the correlation coefficient show
The test considers how closely related two sets of data are
How do you work out the correlation coefficient
Rank from lowest to highest
Work out d which is R1 - R2
Square the answers
Add them up to the sum of d^2
Rs = 1 - 6(sum of d^2 / n(n^2 - 1) )
After working out correlation coefficient how do you then use the degree of freedom table
work out df
df= n1 + n2 -2
Compare your r value to each column
The 0.1 column states that you can 90% confident the data are correlated
The 0.05 column states you are 95% confident
0.025 = 97.5% confidence
0.01= 99% confidence
what are adaptations
Characteristics that increase an organisms chance of survival and reproduction in its environment
what are the three types of adaptations and give examples for each
Anatomical:
Body covering, Camouflage, Teeth, Mimicry
Behavioural (2 main categories = innate/instinctive and learned):
Survival – rabbits freeze when think they’ve been seen
Courtship – scorpion dance
Seasonal - Migration or Hibernation
Physiological:
Poison production, Antibiotic production, Water holding
what is convergent evolution
when 2 species evolve similar characteristics independently of one another because they have adapted to live in similar environments.
what are the adaptations of marram grass
curled leaves to minimise surface area
hairs on inside surface to trap moist air, reducing the diffusion
sunken stomata to limit transpiration
thick waxy cuticle reducing water loss through evaporation
what are some examples of convergent evolution
marsupial and placental mice - both small and agile
flying phalangers and flying squirrels - gliders that eat insects and plants
marsupial and placental moles - borrow soft soil and streamlined
what are selection pressures
factors that affect the organism chance of survival or reproduction
what is the process of natural selection
1) organisms in a species show variation caused by differences in their genes. new alleles could come from a mutation
2) Organisms best adapted to the selection pressures have a better chance of surviving and successfully reproduce. “survival of the fittest”
3) These organisms pass the advantageous allele onto their offspring
4) the process repeats over generations so over time the proportion of individuals with the advantageous adaptation increases. the frequency of the allele increases in the gene pool
5) over long periods of time, a new species could evolve
how has an antibiotic resistant bacteria recently evolved
MRSA
Bacteria reproduce very rapidly so evolve in a short time
when bacteria replicates, their DNA can be altered
a mutation developed which made MRSA resistant to methicillin
resistant ones survived and reproduced whereas the non-resistant ones died
how have peppered moth recently evolved
before the industrial revolution most peppered moths were pale as they were best camouflaged
over the revolution, trees became covered in soot so the pale moths stood out to predators. this meant the black ones survived and reproduced.
this meant the majority of the population of peppered moths were now black
since the clean air act of 1956, pollution has reduced, so trees are once again becoming lighter so the frequency of the pale allele in the moth gene pool has increased.
how have sheep blowflies recently evolved
a pesticide was developed to kill the blowflies which are fatal to sheep
within 6 years they had developed a high level of resistance to the pesticides
this was because the flies had a pre-adaptation which meant some were already resistant
the ones with the gene survived and passed it onto their offspring
how has flavobacterium recently evolved
live in waste water produced from factories
the bacteria have evolved to digest nylon which is beneficial to humans because they can clear factory waste
also it’s beneficial to the bacterium because they have another source of nutrients
