science year 10 evolution

what makes a question scientific or investigable

testable, measurable, and controllable TMC

it’s none of these things if it asks for opinions or preferences or is too vague

define mutations

changes to the sequence of the nucleotides in an individuals genome (DNA)

define mutagens

environmental factors that can increase the frequency of mutations

what do mutations do

change the sequence of nucleotides. this can affect the codons being read and expressed and therefore the amino acid chain (protein)

eg of effect: CAU →UAU

eg of no effect CAU → CAU

what’s genetic mutation

commonly occurring during dna replication in the lead up to mitosis and meiosis, change of one nucleotide

what’s chromosomal mutation

affects all or most of a chromosome and occurs during the chromosome lining up and dividing during cell division. eg trisomy 21 - down syndrome

what’s point mutation

a change to a single nucleotide

EG: THE CAT ATE THE RAT → THE CAR ATE THE RAT

the effect could be small to none. only one nucleotide is affected, the remaining codons r unchanged

what’s frameshift mutation

a deletion or insertion or a nucleotide

eg THE CAT ATE THE RAT → THE CAT TAT ETH ERA T or THE CAT TET HER AT

the effect is all the codons are changed after the frameshift mutation, so proteins could be greatly affected

mutagens can increase the frequency of mutations. what r the 3 types of mutagen

chemicals, radiation, ultraviolet(uv) light

what r the 5 principles of evolution by natural selection

VISTA: variation, inheritance, selection pressures, time, adaptation

define divergent evolution

develop in different directions

define convergent evolution

develop in the same direction

define analogous evolution

similar in some way to another thing or situation and therefore able to be compared with it

what does divergent evolution involve

species evolving different traits from a common ancestor. often evident in homologous structures

eg pentadactyl limbs all come from a common ancestor, but have different functions

what does convergent evolution involve

occurs when unrelated species independently develop similar traits

eg both bats and butterflies have developed wings in response to similar selection pressures, not shared ancestory

what does analogous structures involve

those that r similar but have evolved independently of eachother. come from convergent evolution

eg both sharks and dolphins need to move through water fast enough to catch fish and escape predators. they’ve both evolved to have a streamlined body with fins and fails

define speciation

process where one species gives rise to a new distinct species

define selection pressures

factors that impact organism survival and provide an advantage to certain traits

what is vista

Variation: exists within a species

inheritance: traits can be passed onto offspring

selection pressures: favour certain traits within an environment

time: allows for favoured traits to increase in a population

adaptation: leads to evolutionary change

what’s speciation exactly

evolutionary process that takes us from a common ancestor to a new, distinct species. a new species emerges when populations change so much from one another that they can no longer interbreed to produce viable fertile offspring

what’s isolation

isolatjon limits interactions between groups, leading to unique traits and potentially new species evolving. this limits inheritance

when does speciation occur

when there’s a variation in a species. the species r isolated. they have different selection pressures. over time allele frequency change. eventually the species changes enough and is unable to reproduce with the original species

evolution occurs via

natural selection

variation

inheritance

selection pressures

time

adaptation

what r the 3 types of isolation

genetic:Differences in genetic makeup prevent successful reproduction.

geographic: Physical barriers prevent populations from mating.

social: Differences in behavior or social structures prevent mating.

how to correctly draw a graph

T.U.L.I.P: title, units, labels, impeccably neat by using a ruler, pencil

x is the independent variable

y is the dependent variable

what’s natural selection

the increase or decrease in the frequency of certain alleles within a population. the change in alleles may be caused by biotic(living) or abiotic(non living) pressures

what happens to organisms with beneficial phenotypes

they’ll be better equipped to survive, reproduce, and therefore pass their advantageous genes on which makes it become more common in the gene pool overtime

is natural selection random

yes due to having no specific end goal aside from making organisms best suited to their environment. it’s a process in which an organism adapts through nature selecting for genes that code for advantageous phenotypes

how can members of populations of a species remain the same species

if they’re able to interact and reproduce viable(produce themselves) offspring. they can pass genes between their gene pools. therefore they’ll remain the same

talk about competition

competition between organisms can occur for food, mates and habitats. weaker organisms are likely to be outcompeted and will often die before being able to pass on their genes. this is necessary because it means only organisms with phenotypes advantageous to survival will live to reproduce and pass on their genes

what’s speciation

the process by which one species splits into two or more separate species

what’s artificial selection (selective breeding)

when humans intentionally breed plants or animals with certain desirable characteristics

are organisms with undesirable traits allowed to breed

no. genetic diversity is decreased bc only a small number of individuals with desirable genes r selected to breed. due to this, undesirable genes disappear from the gene pool

steps involved in artificial selection

1. choose parent organisms that show desired traits and breed them

2. choose the best offspring from these parents to breed the next generation

3. repeat the process across many gens, over time the desired traits will become more common

why would species in artificial selection die if a disease were to strike

because it reduces genetic diversity, so most will die out due to the lack of variation in phenotypes