Darwin's Theory of Evolution (and Variants)

Darwin's Theory of Evolution (and Variants)

Asserts that organisms have changed over time to adopt to the unique and varied demands of their changing environments

Organisms have different traits that may be slightly different than their parents, and we call these variants (variation on the parents)

e.g. Giraffe w/ longer neck than parents that’s a random variation. That occurred because the way the DNA got combined when they reproduced.

Advantageous or Disadvantageous? Depends on Environment which an Organism Exist.

depending on the environment, in which giraffes exist.

e.g. if there’s high trees where there’s fruit other giraffe’s can’t reach because they have shorter necks, he enjoys the food exclusively, he’ll feed, be healthy, reproduce, and pass on the trait to eventual propagate.

However, if trees are short, extra neck length may slow the giraffe down, more suseptible to predators

Overall Idea of Organisms Adapting

The traits that they’re advantageous get propaganda and organisms, who have disadvantageous traits end up dying overtime

That’s how we get evolution of different types of organisms

Supporting Evidence for Evolution

1. Fossil Records

2. Comparative anatomy

Fossil records

Look at fossil records of different organisms over time and see how minor variations have occurred and how one organism led to the next

Comparative Anatomy

Comparative Anatomy: Look certain type of animals, whales, they have little feet buried under their blubber. Useless to them, but they’re a vestigial remain from when they were a land based animal.

e.g. DNA sequences between hippos and whales see they’re similar even tho they’re diff creatures

Adaptation vs Acccommodation

Pair of terms we gotta know how to differentiate

Adaptations (Genetic Change)

Changes at the genetic level, allowing a population to respond to the Long long-term change in the environment

• affects population not just me as an individual

e.g. trees getting taller and taller, giraffes in that region evolve a longer neck to be able reach fruit on those trees. This has to over gens

Also, dilatation of the human eye changes temporarily as a temporary change in the environment amount of light

Accommodations (Non-Genetic Change)

Non-genetic changes, allowing individual organisms to respond to Temporary Changes in the environment

e.g.

When cold out, the blood vessels in your body contract, conserving heat. When it gets when warmer, they’ll expand again increasing blood flow. Not a genetic change.

Ability to contract blood vessels- Evolutionary

Action itself- is an accommodation