Chapter 10 - Classification And Evolution Flashcards
What is classification
And why is it useful
The act of arranging animals and plants in taxonomic groups according to their observed similarities
Provides information about organisms
Provides information about relationships between organisms
Easier for scientists to share information
What is taxonomy
The study of classification
What are taxonomic groups
The hierarchical groups of classification
Why do scientists classify organisms
To identify species
- species an organism belongs to is easily identified
To predict characteristics
- species in the same group likely to share characteristics
To find evolutionary links
- similar species likely to share a common ancestor
Easier to share research worldwide
- links between different organisms around the world can be seen
3 domains
Archaea
Bacteria
Eukarya
Taxonomic hierarchy named
Domain Kingdom Phylum Class Order Family Genus Species
Name all 5 kingdoms
Animalia Prokaryotae Plantae Protoctista Fungi
Features used to classify organisms into
Prokaryotae
Bacteria = ecoli
Unicellular Prokaryotic No nucleus No membrane bound organelles Less than 5um
No visible feeding mechanism
Features used to classify organisms into
Protoctista
Algae, protozoa, amoeba
Eukaryotic
Unicellular mainly
Usually live in water
Some have chloroplasts
Features used to classify organisms into
Fungi
Mushrooms , moulds, yeast
Eukaryotic Unicellular or multicellular Have nucleus and membrane bound organelles Chitin cell wall No chloroplasts or chlorophyll Food stored as glycogen
Saprophytic feeders
Features used to classify organisms into
Plantae
Flowers, mosses, ferns
Multicellular Cellulose cell wall Has nucleus and membrane bound organelles Has chloroplasts and chlorophyll Food stored as starch
Autotrophic feeders
Features used to classify organisms into
Animalia
Molluscs, reptiles, nematodes
Multicellular No cell wall Nucleus and membrane bound organelles No chloroplasts Food stored as glycogen
Heterotrophic
What is a saprotrophic feeder
Absorb substance from dead or decaying matter
What is an autotrophic feeder
Produces their own food
What is a heterotrophic feeder
Consumes plants and animals
How to use nomenclature
Called the binomial system
Genus + species
Underlined
Advantages of the binomial system
- organism can be easily classified
- helps avoid confusion, each name is unique
- universal recognition
- useful in identifying relationships between organisms
What is phylogeny
The study of the evolutionary history of groups of organisms
Reveals which organism is related to and how closely related
What is the relationship between classification and phylogency
Phylogeny is used to confirm that the classification groups are correct, and if not, causes them to change
Advantages of phylogeny
Takes into account evolutionary relationships
Forms a continuous tree so organisms don’t have to be forced into a group
Is not hierarchical therefore can be compared
Easy to observe relationships
6 kingdoms vs 3 domains
Prokaryotae split into
Archeabacteria eubacteria
Single celles prokaryotes
What evidence did woese base his new system on
The sequences in nucleotides in the cells ribosomal RNA
The cell membranes lipid structure and their sensitivity to anitbiotics
Eukarya 80s ribosome
Archea 70s ribosome
Bacteria 70s ribosome
Why was the prokaryotae been reclassified into 2 domains
Because there is a large difference between archaea and bacteria
They have evolved separately
Archaea head is more closed related to eukarya
What are the differences between archaea and bacteria
MOLECULAR EVIDENCE
Have different ribosomal RNA
Different enzyme RNA polymerase
Archaea, not bacteria, has similar histones to eukarya
CELL MEMBRANE EVIDENCE
Different bonds of the lipids in the cell membranes
Different development and composition of flagellae
How is molecular evidence used in classification
Looks at the similarities in proteins in DNA
How DNA is stored
Sequence of DNA bases
Sequence of amino acids in proteins
How is embryological évidence used in classification
Compares similarities in early stages of organisms development
How is anatomical evidence used in classification
Similarities between the function and structure of different body parts
How is behavioural evidence used in classification
Compares behaviour and social organisation of organisms
What is variation
Differences that exist between individuals
What is intra specific variation
Variation within a species
- height
- colour
What is interspecific variation
Variation between different species
Bird
- the lightest bird is 1.6g
- the heaviest is 160kg
What can variation be caused by
Genetic factors
Environmental factors
Both
Genetic factors that cause variation
- variation of alleles amongst a species
- mutations change DNA sequence and therefore genes - change proteins that affect physical and metabolic characteristics
- meiosis - random assortment and crossing over of maternal and paternal - inherits genes from each parent
- random fertilisation
Environment factors that affect variation
Climate
Food
Lifestyle
Eg. Scars, piercings, hair length
Environmental and genetic factors that cause variation
Genetic - determine what the organism CAN have
Environmental - determines what the organism actually is
Environment influences genetics
Eg. Height , weight ,
Flagellum - some only grow in particular environments - metal ions present
What is standard deviation used for
A measure of the spread of values about the mean
If large standard deviation = Varies a lot
What is the chi squared test used for
Compare the differences in expected and observed values
What is the T test used for
Compare mean data to see if there is a significant difference
Between 2 things
What is spearman’s rank used for
To find if there is a positive or negative correlation between 2 sets of data
What is continuous variation
Individuals within a population vary within a range
What is discontinuous variation
Organisms variation falls in distinct categories
Name three different types of adaptations
Behavioural
Physiological
Anatomical
What are anatomical adaptations
Structural features of an organism that increase its chances of survival
How do adaptations benefit organisms
Has features to increase its chances of survival, reproduce, and have offspring that can also reproduce and carry advantageous gene
What are physiological adaptations
Processes that take place inside the body that increase its chances of survival
What are behavioural adaptations
The way an organism acts to increase its chances of survival
Anatomical advantages examples
Camouflage
Teeth
Otters - streamlined shape
Physiological examples
Some bacteria secrete antibiotics, to kill competition
Bears hibernation - lowers metabolism, conserves energy, doesn’t have to look for food
Behavioural adaptations examples
Survival - possums play dead
Courtship - scorpions dance to attract mate
Seasonal - migration
What are innate behaviours
Behaviour inherited by genes
- spiders build webs
What is learned behaviour
Adaptations learnt from experience and observation
- otters use rocks to crack shells
Why do organisms from different taxonomic groups show similar anatomical features
Have evolved in similar environments and to fill similar ecological niches
Features of marsupial mammals
Short gestation period
Don’t develop full placenta
Born early in development
Continue to develop once born
Features of placental mammals
Longer gestation periods
develop a placenta
Born fully developed
Why do Marsupial moles and Placental moles look alike but are not closely related
Similar anatomical features because they evolved in similar environments - both live in tunnels, burrow for food
- small, non existant eyes
- no external ears - streamlined
- come shaped head, tube shaped body - easy to burrow
- scoop shaped claws
What different types of evidence are used in classifcation
observational behavioural molecular embryological anatomical
What is the theory of evolution
Darwin and Wallace
Individuals in population show variation in phenotype
Sélection pressures create struggle
Individuals with better adaptations more likely to survive
Pass on advantageous gene
Wallace contributed - less well known
What is phenotype
A set of observable characteristics of an organism from the interaction of its phenotype with the environment
What is genotype
The genes and alleles of an organism
3 types of evidence that supports evolution
Fossil records
DNA evidence
Molecular evidence
How do fossils show evolution
Fossils = preserved remains in rocks
Can be arranged in chronological order, to view gradual changes in organisms
Can be used to compare living organisms to extinct ones
How does DNA evidence suggest evolution
Closely related species have diverged more recently
Share similar DNA
Less time for base sequences to change
- similar DNA = Closely related
How does molecular evidence suggest evolution
Compare sequences of amino acids in proteins
Compare antibodies
Closely related = similar molecules
Less time has gone for changes to happen
How the evolution of pesticide resistance has implications for humans
- if disease carrying pesticides become resistant - spread of disease increases
- population of insects can become resistant to all pesticides = lots of money to reproduce
- takes while to farmers to figure out which pesticide will work
- crops eaten
- pesticides might have to be broader - kill beneficial insects
How the evolution of drug resistance has implications for humans
- infections by drug resistant pathogens are harder to treat
- if résistant to a lot of drugs - could take long time to find one that will work - patient could die
- costs a lot to make new drugs
