Evolution

evolution

the process through which species change over time through genetic variation and natural selection

natural selection

the process of traits which are more suited to the environment being selected to reproduce

homologous structure

a structure in different species that has a similar structure but serves different functions

hominid

species similar to humans

vestigial structure

a structure that no longer serves a function for the organism

artificial selection

when humans make a species change overtime

speciation

when different populations in a species differentiate so much that they become different species

Charles Darwin

created the correct explanation for how and why species evolve

Hutton and Lyell

showed evidence that the Earth is old (4.5 bill)

Lamark

was right about evolution but wrong about how it happens

Malthus

struggle for survival

what led Darwin to create his theory of evolution

he saw how species that lived in different places had different structures

variation

different structures within a species, allows evolution to happen by making something to select

why some variations are more common than others

some structures are more advantageous to have variation and some are better closer to average

overproduction

there needs to be competition for some traits to be selected over others

reproductive advantage

some organisms will have structures that make it more likely for them to reproduce than others

fossil records

shows that species have changed over time

micro evolution

evolution we can see, bacteria, bugs, etc

how DNA helps theory of evolution

all organisms use ATCG

key adaptations for humans/hominids

fire, tools, walking upright, building shelter, etc

when hominids first appeared

6-7 million years ago

when homo sapiens first appeared

200,000 years ago

3 main steps in speciation

isolation, adaptation, separation

isolation

one population of a species is separated from another; physically, reproductively, behaviorally

adaptation

different populations adapt to different environments

separation

eventually a species becomes so different it can’t interbreed with others