4.3 classification and evolution Flashcards
define binomial system
system that uses the genum and species name when naming animals to avoid confusion
Why do we classify things?
for convenience
to make the study of things more manageable
to make it easier to identify things
to help see relationships between species
What is the classification hierarchy?
domain
kingdom
phylum
class
order
family
genus
species
Define domain
highest taxonomic rank
eukaryotae, archea and eubateria
define kingdom
there are 5 kingdoms
protoctista, eukaryota, plantae, animalia, fungi
define phylum
groups species with similar body plans
define class
organisms that possess similar traits such as number of legs
define order
subdivision using additional information such as diet
define family
group of closely related genera
define genus
group of closely related species
why is the binomial naming system used
to avoid confusion
different species may have the same common name
or the same species may be called different common names in different areas
What is the biological definition of a species
organisms that can freely interbreed to produce fertile offspring
What is the phylogenetic definition of a species
group of individual organisms that are similar in biochemistry anatomy genetics and appearance
explain why better microscopes lead to improved classification
better microscopes made it clear that many single celled organisms share features of both plants and animals
why were fungi difficult to classify
their hyphae grow into their surroundings similar to roots but they do not photosynthesise
define autotrophic
absorb simple molecules and build them up into larger organic molecule
define saprophytic
cause decay
define heterotrophic
digest large organic molecules to form smaller molecules
describe the prokaryotae kingdom
have no nucleus only a loop of free DNA
no membrane bound organelles
smaller that eukaryotes
may be free living or parasitic
describe the protoctista kingdom
show a wide variety of forms and can display animal or plant like features such as nutrition
eukaryotic
mostly free living
mostly single celled
describe the fungi kingdom
eukaryotic
have walls made of chitin
saprophytic nutrition
cytoplasm that is multinucleate
describe the plantae kingdom
eukaryotic
multicellular
cellulose cell wall
contain chlorophyll
autotrophic
Describe the animalia kingdom
eukaryotic
multi cellular
heterotrophic
usually able to move around
define convergent evolution
two unrelated species that adapt in similar ways and therefore look similar
why can biological molecules be used as evidence in classification?
certain large biological molecules are found in all living things
two organisms with similar molecules will be closely related
what is cytochrome c
protein used in respiration
how can cytochrome c be used in classification
if the sequences are the same the two species are closely related
if the sequences are different the organisms arent closely related
what other biological molecules can be used as evidence in classification
DNA
Describe why the three domain classification system was introduced
he divided the prokaryotae domain into archae and eubacteria as they were bothe significantly different
What are some differences between archeae and eubacteria
different cell membrane
different enzymes for synthesising RNA
different mechanisms for DNA replication
define phylogeny
study of evolutionary relationships between organisms
define artificial classification
based on only a few characteristics
doesn’t reflect evolutionary relationships
provides limited information
is stable
describe natural classification
uses many characteristics
reflects evolutionary relationships
changes with advancing knowledge
provides useful info
define natural selection
the term used to explain how features of the environment apply a selective force on reproduction of individuals in a population
How did Wallace contribute to Darwins conclusion
He was a naturalist that came to the same conclusions as Darwin
What 4 observations did Darwin make
offspring generally appear similar to their parents
no two individuals are identical
populations in nature tend to remain fairly stable
organisms have the ability to produce large numbers of offspring
What 3 conclusions did Darwin come to
there is a struggle to survive
better adapted individuals survive and pass on their advantageous alleles to their offspring
over time a number of changes gave rise to a new species
how were fossils evidence for evolution?
Showed that the world was inhabited by species that are different to those today
old species have died out and new ones have arisen
new species often appear similar to the old ones
how are biological molecules evidence for evolution
the fact that certain molecules are found throughout the living world
two closely related species will have similar biological molecules
biological molecules differ more between species that diverged a long while ago
define intraspecific variation
variation between members of the same species such as eye colour
define interspecific variation
variation between species
define continuous variation
variation where there are two extremes and a full range of intermediate values between them
e.g. height in humans
length of leaves in an oak tree
Define discontinuous variation
variation where there are distinct categories and nothing inbetween
e.g. gender
blood type
What are the causes of variation
genetic
environmental
Describe genetic variation
the genes we inherit from our parents are used to provide information that define our characteristics and the alleles that we inherit are not the same as that in any other living thing
our combination of characteristics is completely unique
Describe environmental variation
characteristic affected by our environment
e.g. an overfed pet will become obese
sun exposure can make a persons skin darker
What are the combined effects of genetic and environmental variation
not all our genes are active at any time and changes in the environment can affect which genes are active
over the centuries the human population has become taller but if your family is short you will most likely remain short
define adaptation
characteristic that enhances survival in a habitat
What will a well adapted organism be able to do
find enough water and food
defend itself from predators and disease
respond to changes in its environment
have sufficient energy to reproduce
define anatomical adaptations
anatomical structural features
give examples of anatomical adaptations
marram grass:
long and wide roots
curled leaves to reduce surface area
lower epidermis covered in hairs
low density of stomata
thick waxy cuticle
define behavioural adaptations
the way an organisms behaviour is modified for survival
give some examples of behavioural adaptations
when touched the earthworm contracts and goes back to its burrow
marram grass responds to a shortage of water by rolling its leaves
define physiological adaptations
affect the way processes work
give some examples of physiological adaptations
specialised hinge cells which roll marram grass leaves
stomatal closure lignified cells in the leaves to maintain turgidity
what animal is an example of convergent evolution
marsupial and placental moles are both burrowing animals so they have adapted in similar ways and may look similar
small eyes
cylindrical body
strong front legs with claws
