Biology Unit 2

Species

A group of organisms that breed together and produce fertile offspring

Variation

different characteristics within a species

Characteristic

a feature in a species

inherited variation

is caused by genes mutations and DNA passed from your parents

inherited characteristics

eye colour, blood type

environmental characteristics

language, religion, piercings, scars, hair length

characteristics of both

height, skin colour, weight, hair colour

Mendel discovered

you inherit traits from both your parents

continuous variation

normally something you can measure. it’s a number in a range

discontinuous variation

Is something you have or don’t have. Something you can do or not do. I doesn’t have a number range.

continuous examples

height, weight, handspan

discontinuous example

eye colour, rolling your tongue

dependant variable

what you measure (y axis)

independent variable

what you change (x axis)

organisms competed for

water, light, space, food, mates, minerals

adaptions

when competing with other animals the best competitors are stronger, smarter and better at spotting prey. Spotting prey might require good hearing or sight. These features are called adaptions.

Hot climate adaptions

no reliance on sweat to cool down, Hunt during the night, thin layer of body fat under skin, camouflage isn’t white, survives on small amount of water, large thin ears, thin silky fur, large surface area to body mass ratio, not necessarily black eyes or nose

cold climate adaptions

small surface area to body mass ratio, survive on normal amount of water, large layer of fat under skin, thick fur, hunt during the day, normal reliance on sweat, black eyes and nose, camouflaged white or grey, small ears

the nucleus of the cell has

chromosomes

genes are sections of

dna , genes code for proteins, proteins produce characteristics

dna is made up of

bases

chromosome

long strand of dna

dna is a ……….. …….. shape

double helix

rosalind franklin studied dna using

x-rays

photo 51 was taken in

1952

every cell has …… chromosomes

46

what cells have 23 chromosomes

gametes

rosalind franklin discovered

dna was a double helix shape

evolution

the process by which living things can gradually change over time

evolution takes ……………. of years

millions

according to scientists all animals have a common ……………, which was a …………. …………

ancestor, simple organism

3 types of evidence for evolution

fossil, dna, observational evidence

mutation

a change in the DNA sequence of an organism. some of these cause variations that are advantageous to the animal

natural selection

organisms with characteristics most suited to their environment can reproduce and pass on their genes are characteristics

example of natural selection

peppered moths, giraffes, praying mantis

extinction

is when all members of a species die, this normally happens when a species isn’t adapted to it’s environment

causes of extinction

travelling, urbanisation, virus, climate change, loss of habitats, poaching, hunting, pollution, invasive species, predators, natural disasters

interdependency

if one animal in the food chain becomes extinct it can make other animals in the chain at risk

a gene bank

stores genetic material of plants and animals to preserve species, they are conservation efforts

seed banks

\-18 degree freezers

tissue banks

buds and other cells of plants stored

cryobanks

seeds or embryos are stored at very low temperatures using liquid nitrogen

there are 4 types of banks, seed banks, tissue banks, cryobanks, and

pollen banks

selective breeding

a sped up artificial evolution where parents are chosen to replicate desired traits

after 1 round of selective breeding

the best offspring from the parents are selected and bred together

selective breeding takes

decades

cloning

is making a genetically identical copy of an individual

cloning happen naturally in

asexual reproduction

plant can be cloned by

cutting them and planting then in growth hormones

cloning diagram

cloning and selective breeding similarities

ethical issues, requires human involvement, reduce in genetic variation, reproduction/new animal, enhances or replicates desired traits

only cloning

is lab dependent, helps prevents extinction, modern technique, takes shorter amount of time, more reduction in genetic variation

only selective breeding

doesn’t rely on labs, is an ancient technique, takes decades