Genetics and Variation Flashcards
What is an allele?
Different forms of the same gene
What is a gene?
section of dna that codes for a particular characteristic
What is a genotype?
The two alleles for a gene
What does homozygous/heterozygous mean?
if the genotype is made up of the same/ different alleles
What is a characteristic only expressed in a homozygous genotype?
Recessive
What is a characteristic only expressed in both homozygous and heterozygous genotypes?
Dominant
What are genes made of?
DNA
What is another word for discontinous variable?
Discrete
what is phenotype?
physical appearance based of genotype
What is a punnet square?
A square where you write down alles and work what percentage chance you have of getting different characteristics
What is environmental variation?
Difference in characteristics not based of dna
Describe the process of speciation
-population becomes geographically isolated from original
-new population exposed to new environmental conditions
-mutations may occur, creating variation and new phenotypes in new population
-natural selection means those best adapted survive & pass on genes
-over time the new population changes to a point where it can’t interbreed with the old one
Mnemonic for taxonomy
(do) Kangaroos Prefer Cake Or Frosting, Generally Speaking?
Kingdom Phylum Class Order Family Genus Species
What did Wallace do?
noticed asian animals were very different to those in australia
Named the land divide the wallace line
Theorized they’d once been similar but seperated by tectonic plates
what can caused the geographical divide that starts the process of speciation?
mountain formation
continental drift
splitting of habitats (building roads, deforestation)
What is extinction?
extinction occurs when no members of a species are left alive
What can cause extinction?
invasive species
pollution
habitat loss
over consumption/exploitation
population growth (humans)
changes to environment (ph temp)
extreme events
what is a species?
a species is a group of organisms with similar characteristics and can interbreed to produce fertile offspring
What are the characteristics of Animalia?
Eukaryotes
multicellular
no cell wall
heterotrophic
movement
what are the characteristics of Plantae?
Eukaryote
multicellular
cell wall
phototrophic
movement
what are the characteristics of Fungi?
Eukaryotes
single and multicellular
cell wall
heterotrophic
movement
what are the characteristics of protists?
eukaryotes
single celled
some have cell walls
both heterotrophic and phototrophic
movement
what are the characteristics of Prokaryota?
prokaryotes
single celled
cell wall
both phototrophic and heterotrophic
movement
what are the five kingdoms?
animalia, plantae, fungi, protists, prokaryota
Which kingdoms are heterotrophic?
animalia, fungi, protists, prokaryota
which kingdoms are phototrophic?
plantae, protists, prokaryota
what is a heterotroph?
an organism that cannot produce its own food
what is a phototroph?
an organism that can produce its own food
what are the three domains?
bacteria, archaea and eukaryota
