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What is evolution?

The cumulative change of heritable gene controlled characteristics over many generations


How do fossil records show evolution?

- they show the gradual change of species over time
- the timeline in which fossils appear are what are expected with bacteria and algae oldest, followed by shelled animals, then dinosaurs, early reptiles and then birds and mammals


How does selective breeding show evolution?

- shows record of recent changes in genetic characteristics over a few dozens of generations


What are homologous structures?

- common internal structures that are similar in seemingly dissimilar animals which have evolved from a common ancestor


What is the example of a homologous structure?

The Pentadactyl limb, which is a five digit limb found in animals, such as humans, dolphins, bats and dogs


What is speciation?

When 2 populations of the same species become separated so they cannot interbreed, natural selection will act differently on those 2 separate populations. These are will become recognisably different over time.


What is evidence for evolution?

-Fossil records
- selective breeding
- homologous structure
- speciation


What causes genetic variation?

-In meiosis there are 2n possible variations of chromosomes in the sex cells
- crossing over of homologous chromosomes in prophase 1
- genetic mutations where new alleles are produced


How does struggle for survival contribute to natural selection?

- populations produce more offspring than the environment can support
- this causes an increased demand for resources
- which causes competition within a population
- those with beneficial genetic traits out compete and survive and reproduce


How does antibiotic resistance happen?

- anti- biotics kill or weaken bacteria so your immune system can fight the pathogen
- some bacteria might not die due to changes in DNA- mutations and thy transfer an antibiotic resistant gene
- this is more likely to occur if the proper amounts of antibiotic aren’t taken or a course isn’t finished
- resistant bacteria survive and reproduce and make you sick in the future


What two parts are in binomial nomenclature?

Genus and species


What are the 3 domains?

Eukaryotes, bacteria, archea


What is a dichotomous key?

A key constructed of a series of statements arranged into pairs. The two descriptors represent separate choices or characteristics that determine the difference between 2 organisms


What are the characteristics of bryophytes?

No vascular tissue, very small, spore to reproduce. Example- moss


What are the characteristics of filicinophytes?

Vascular tissue, use spore to reproduce, ex- fern


What are characteristics of coniferophytes?

Vascular tissue, use naked seeds to reproduce, woody. Ex- pines


What are characteristics of angiospermophytes?

Vascular tissue, produce flowers


What are characteristics of Porifera?

Sponges- no mouth or anus, filter food from current, attached to rocky surfaces


What are characteristics of Cnidaria

Jellies- radical symmetry, has mouth but no anus, stinging cells


What are characteristics of Platyhelminthes

Flatworms- bilateral symmetry, mouth and but no anus, no segmentation


What are characteristics of Annelida?

Segmented worms- bilateral symmetry, mouth and anus


What are characteristics of mollusca?

Squid- bilateral symmetry, mouth and anus, shell


What are characteristics of Arthropoda?

Insects- bilateral symmetry, mouth and anus, jointed, exoskeleton


What are the characteristics of of mammals?

- 4 pentadactyl limbs
- lungs w alveoli
- internal fertilisation
- give birth
/ hairs from skin
- teeth including living tissue


What are characteristics of birds?

- 4 pentadactyl limbs, 2 limbs modified as wings
-lungs with parabronchial tubes
- internal fertilisation
- hard shells around eggs
- feathers
- beaks


What are the characteristics of reptiles?

- 4 pentadactyl limbs
- lungs with extensive folding
- internal fertilisation
- soft shells around eggs
- dry scaly impermeable skin


What are characteristics of amphibians?

- 4 pentadactyl limbs
- simple lungs with small internal folds and moist surfaces
- external fertilisation in water
- protective jelly around eggs
- laval stage lives in water
- soft moist permeable skin


What are the characteristics of fish?

- fins
- external fertilisation
- scaled from the skin
- single full slit
- swim bladder for buoyancy


What is a cladogram?

A tree diagram showing similarities between species


What do nodes show?

A speciation event when a common ancestor splits into 2 or more species


How is evidence for which species is in a clade obtained?

Amino acid sequences of certain proteins and base sequences of genes


What is a molecular clock?

The rate at which mutations occur


What is analogous structure?

When some animals belonging to different groups live in similar habitats develop simple similar structures, but have no common ancestor


What are the properties of bacteria domain?

Circular chromosomes
No histoines
No introns in genes
Peptidoglycin cell wall
Ester lipids in cell membrane with D glycerol


What are properties of archaea domain?

Circular chromosomes
Histoines present
No introns in genes
Has cell wall
Ether group in cell wall, L glycerol


What are properties of eukaryota domain?

Linear chromosomes
Has histoines
Has introns in genes
Rarely has cell wall
Eager bond in lipids with D glycerol