Classification And evolution Flashcards
What are the 7 taxonomic groups
Kingdom, phylum, class, order, family, genus , species
5 kingdoms
Prokayotae Fungi Plantae Animalia Protoctista
Prokaryotae
Unicellular
No nucleus or membrane bound organelles , ring of naked DNA
No visible feeding mechanism, nutrients absorbed or photosynthesis
Protoctista
Mainly unicellular
Some have chloroplasts
Nucleus and other membrane bound organelles
Some are sessile, but others move by cilia or flagella
Nutrients are acquired by photosynthesis ( autotrophic feeders), ingestion of other organisms ( heterotrophic feeders)
Fungi
Unicellular or multi
Nucleus + membrane bound organelles, cell wall composed of chitin.
No mechanism for locomotion
Most have a body or mycelium made of threads or hyphae
Stores food as glycogen
Plantae
Multicellular
Nucleus + membrane bound organelles, cell wall of cellulose
Contains chlorophyll
Most do not move, some have cilia or flagella
Store food as starch
Nutrients are acquired by photosynthesis, autotrophic feeders
Animalia
Multicellular
Nucleus and other membrane bound organelles , no cell wall
No chloroplasts
Move with aid of cilia or flagella, or contractive proteins, sometimes in the form of muscle organs
Nutrients acquired by ingestion, heterotrophic feeders.
Food stored as glycogen
Reason for new naming system
Traditional 5 kingdoms were: prokaryotae, protoctista, fungi, plantae, animalia
Prokaryotae were actually vastly different so they were split into 2 kingdoms eubacteria and archae-bacteria
With eukarya, bacteria and acrchea as the 3 domains
Archea bacteria
Ancient bacteria that can live in extreme environments
Hot , anaerobic, acidic
Eubacteria
Known as true bacteria
Found in all environments
Domains of new system
Bacteria, archaea, eukarya
Phylogeny
Name given to the evolutionary relationship between organisms
Evidence for evolution
Palaeontology- study of fossils
Comparative anatomy- similarities and differences between organisms anatomy
Comparative biochemistry- similarities and differences in chemical makeup
Homologous structures
A structure that appears significantly different , and may perform different functions, in different organisms but has the same underlying structure
Evidence of evolution - palaeontology
Simplest organisms are found in the oldest rocks, vertebrates found in new rocks supports theory that life forms evolved over time, into more complex organisms
Sequences, plant fossils appear before animal fossils
Studying anatomy, can show that closely related species evolved from the same ancestor
Allows Relationship between Extinct and living to be investigated
Comparative biochemistry
Study proteins and other molecules that control life processes.
Some of these remain unchanged (highly conserved) among related species, slight changes that occur in these molecules can identify evolutionary links.
Neutral substitutions , those that do not effect function, occur at a regular rate (rate is different for different molecules).
Change in molecular sequence of a particular molecule is compared against the rate of neutral change to understand where the organisms last shared a common ancestor
Evolutionary by natural selection
All living organisms produce more offspring than make it to adulthood
Only the strongest survive to pass on their genes and therefore characteristics to their offspring
Causes of variation - genetic
Random alleles
Mutations
Meiosis, random
Sexual reproduction, genes from each parent
Chance- many different gametes are produced to hope that one fertilises, individuals differ from siblings
Continuous variation vs discontinuous
Animals ; continuous - height Discontinuous- blood type
Plants- size ,discontinuous
Microorganisms- continuous size , Discontinuous shape
Environmental variation
Access to sun or water
Random pollination
Anatomical adaptations
Physical features: hair, scales Camouflage Teeth Mimicry Provide evidence for convergent evolution
Behavioural adaptations
Survival behaviours - play dead , freeze
Courtship- elaborate ways of attracting a mate
Seasonal behaviour- cope with changes of environment, hibernation or migration
Innate behaviour , learned behaviour
Physiological adaptions
Production- venom to kill prey
Antibiotic production- deal with bacteria
Water holding
Marsupial and placental moles
Both burrow through soil to find food
Streamline body shape and limbs for digging
Velvet fur for smooth movement
However they differ in colour, marsupial is white-orange
Placenta is grey
Convergent evolution
When 2 species that are not closely related evolve similar traits due to environmental pressures
How does natural selection occur
1) genetic variation
2) selection pressure
3) how this effects reproductive success
4) how this results in increased population possessing the advantageous characteristics
How does evolution in other species effect humans
Antibiotic reliance in microorganisms
Makes infection much more difficult to cure like in the 1900s
Why do scientists classify organisms
To predict characteristics
To find evolutionary links
To identify species
Structure if DNA
Double stranded Hydrogen bonds that can easily be broken Both strands act as a template Complementary base pairing a+t c+g
What makes variation continuous
Many genes effecting
Both genetic and environmental factors
Quantitative e.g range of values
No distinct groups
What makes variation discontinuous
Controlled by one or very few genes
Very little environmental effect
Discrete Categories
heterotrophic feeders
Fungi and animalia
Cannot produce own food
Examples of heterotrophic and autotrophic feeders
Prokaryotae and Protoctista
Autotrophic feeders
Plantae
Self feeders
Why do scientists classify organisms
To predict characteristics
To find evolutionary links
To identify species
Link/difference between phylogeny and classification
Classification uses knowledge of phylogeny
- phylogeny produces a continuous tree whereas classification requires discrete taxonomical groups
- hierarchal nature of the Linnaean system can be confusing
How will evolution in other species effect the human population
Bacteria becoming antibiotics resistant
Insects becoming pesticide resistant
