Module 4- classification and evolution Flashcards
What is taxonomy?
identifying, naming and sorting organisms into groups
What are taxa?
groups where closely related organisms are put into
What is the phylogeny of organisms?
evolutionary relationships that helps determine which taxa an organism is part of
Name the taxas
domain, kingdom, phylum, class, order, family, genus, species
Define species
group of organisms that is able to reproduce to produce fertile offspring
Name and describe each kingdom
animalia- largest kingdom with over 1 mil species, multicellular, has nucleus and other membrane bound organelles, no cell walls or chloroplast,moves with the aid of cilia/flagella/contractile proteins, nutrients are acquired by ingestion, food is stored as glycogen
plantae-2nd largest kingdom, multicellular, has a nucleus and other memrane bound organelles, cell wall composed of cellulose, all contain chlorophyll, most don’t move, nutrients are acquired by photosynthesis, store food as starch, 250000 species
protoctista- mainly unicellular, a nucleus and other membrane bound organelles, some have chloroplasts, some are sessile but others move by cilia/flagella/amoeboid mechanisms, nutrients are acquired by photosynthesis (autotrophic feeders) and ingestion of other organisms (heterotrophic organisms)
fungi- can be unicellular or multicellular, has a nucleus and other membrane bound organelles, cell wall mainly composed of chitin, no chloroplasts or chlorophyll, no mechanism for locomotion, nutrients are acquired by absorption mainly from decaying material (saprophytic feeders), most store their food as glycogen
prokaryotae- unicellular, no nucleus or other membrane bound organelles, no visible feeding mechanism, nutrients are absorbed through the cell wall or produced internally by photosynthesis
Name the 3 different domains
archaea, bacteria, eukarya
Who was the first to propose the classification system?
Carl Linnaeus
Why do scientists classify organisms?
to easily identify species, to predict characteristics and to find evolutionary links through common ancestors
Why are mules infertile?
as their cells contain an odd number of chromosomes which means meiosis and gamete production can’t take place correctly as all chromosomes must pair up
What is the classification of humans?
D= eukarya
p= chordata
c=mammalia
o=primates
f=hominidae
g=homo
s=sapiens
How do you write the binomial name?
consists of genus and species of an organism
-must be put in itallics if typed and underlined if written
What have been the recent changes to classification systems?
-originally classification systems were based on observable characteristics/features
-through the study of genetics and other bio molecules scientists are now able to study evolutionary relationships between organisms
-when organisms evolve their DNA changes
-DNA determines the proteins that are made which in turn determines the organisms characteristics
What is the current classification system used by scientists?
3 domain system
who and when was the 3 domain system proposed by?
Carl Woese in 1977
How does the 3 domain system group organisms?
using differences in the sequences of nucleotides in the cells ribosomal RNA (rRNA) as well as the cells membrane lipid structure and their sensitivity to antibiotics
Describe each of the 3 domains
eukarya- have 80S ribosomes, organisms possessing complex sub-cellular structures
archaea- have 70S ribosomes, primitive bacteria
bacteria- have 70S ribosomes, true bacteria
What is a phylogenetic tree used for and what do they show?
-represent evolutionary relationships between organisms
-the point organisms join together is the common ancestor
-shows how different species have evolved from a common ancestor
Where has much of the evidence for phylogenetic trees come from?
fossils
How are phlogenetic trees produced?
by comparing species genetic make up and physical characteristics
What are 3 advantages of phylogenetic trees?
-can be done without reference to linnaean classification
-provides a continuous tree whereas classification requires discrete taxinomial groups
-scientists are not required to put organisms into specific groups that they don’t quite fit into
What did Darwin observe and conclude?
-finches on the Galapogos islands all had different shaped beaks and claws
-he realised this was due to the types of food present on different islands
-the birds with the most well suited beaks to the food on their island were more likely to survive longer and reproduce passing on this characteristic
-overtime all the birds on the island will share the same beak
What did Darwin do when he came back?
-sent specimens back to the UK for other scientists to preserve and classify which enabled them to see first hand the links between characteristics within organisms that Darwin had not
-carried out an experimental breeding of pigeons to gain direct evidence that his ideas may work
-Darwin and Wallace presented their ideas of evolution by natural selection together
Describe the process of natural selection
1)random mutation occurs- in the gene sequence of DNA which can arise spontaneously. new mutations can result in new alleles of a gene
2)variation in mutations- by chance some mutations might confer a beneficial trait. an individual with a beneficial mutation will be more likely to survive and reproduce than an individual without the mutation
3)inheritance- when an individual with an advantageous mutation reproduces, the characteristic is inherited by their offspring
4)change in allele frequency- individuals in the next generation who have the advantageous mutation are also more likely to reproduce and pass on the allele. over many generations the allele will increase in frequency in the population (evolution)
