Evolution Unit Test

What is natural selection?

A process where random indiviuals are selected for in a non random way. Variation of mutations within a population adapted to enviroment to better survive and reproduce. Which passes on favourable alleles to off spring. Repeats over many generations.

What are selective pressures?

Abiotic and biotic factors that put pressure on a population. A trait that gives a specied advatage agaisnt the selective pressures will be passed onto next generation.

Examples of selective pressures

• Changes in temp

• Changes in compeition for food or mate

• changes in predators

• low-light level changes (sunshine)

Evolution define

Changes of a species over time to make it more effient, through adapations to conditions, enviroments and standards over time.

what is a mutation

Changes in DNA that result in new alleles. (Recal mutations from meiosos.)

Mutations are only passed down to ofspring if mutation occurs in the gametes.

Define selective advatage

A trait that was one neutral or a disadvatage becomes favourable in a different enviroment

Adaptations

Process that helps an organism survive and reproduce in an enviroment. And pass down its alleles to its offspring.

Behavioural adaptations

Change in a way an organism acts.

Ex: migration, burrowing, how a bunny runs

Structural adaptations

Visible/physical change of an organism

Ex: camoflage, mimicry

Physiological adapations

Physical change that cant be seen in appearance

Ex: systems during hybernation

What is fitness?

The contribution an individual makes to the gene pool of the next generation. Basically how many babies it has.

Artifical selection

Selective breeding. Humans choosing to breed for certain phenotypes (traits) for human wants and needs.

Consequences of artifical selection

Creates less genetic diversity, meaning the species is more likely to be wiped out by disease. & Inbreeding problems.

Also, when a specific trait is selected for, often other traits become negatively affected

Ex: Bulldog. Has cute smushed face (chosen for by humans), which results in them having respiratory problems

Inbreeding and inbreeding problems

Inbreeding - breeding of closely related relatives

Inbreeding depression - decreaded fitness because unfavourable alleles are maintained and amplified in offspring.

Ideas of Aristotle

Species were immutable - unchanging and unpredictable

scala naturge - “ladder of life” organism ranked on complexitiy

Ideas of Plato

That species were static and unchanged

The first to think about the history of organisms

Ideas of George-Louis Leclar Comte de Buffon

Thought different geographical locations had different types of organisms.

Hypothosized that all quadrupeds are descended from just 38 species

(Closer)

Ideas of George Cuvier

He was a paleontologist. Found the deeper layers in the dirt held older, less complex, and most dissimilar fossils.

Proposed catastrophism because fossils found in one layer could not be seen in the next.

Ideas of James Hutton - 1700s

“Father of geology” - geologist

Disproved the prevailing idea of catastrophism with uniformitarianism.

Gradualism - Current geological features were created by slow but continuous mechanisms that created geological changes over time

Catastrophism

The theory that Earth's geological features and past extinctions were shaped primarily by sudden, short-lived, violent natural disasters rather than slow, gradual changes.

Uniformitarianism

he theory that Earth's geological features were shaped primarily by slow, continuous, and gradual processes operating over vast periods of time, rather than sudden catastrophic events.

Ideas of Charles Lyell

Proposed and popularized uniformitaranism from Hutton.

Ideas of Jean-Babtise Lamark (two wrongs, one right)

Thought characterisits aquired during an indivisuals life time to survive would be passed down to the next generation (WRONG, but influencial)

(RIGHT) Thought organisms gradually developed adaptations to survive their environment.

(WRONG) Principle of use and disuse: Traits used more in an organism’s lifetime became stronger and more prominent, while less used ones became weaker and less prominent.

(WRONG) Principle of inheritance of acquired characteristics: Gains/loses during an individual’s lifetime would be passed down to offspring

Ideas Alfred Russel Wallace

Independently came up with the idea of natural selection completly seperatly from Charles Darwin and confrimed his therioes with Darwin after.

Charles Darwin

Coined natural selection.

Published his thoughts in a book Orgin of Species by Means of Natural Selection

Fossil record - Evidence for Evolution

Physical similarties in fossils. Can see adapations that happened at a structural/physiological level over periods of time.

Showing species once extinct, showing change over time.

Old fossiles on bottom, newer with every next layer. + Simple to complex

Analogous Structures - Evidence for Evolution

Body parts on different species that have a similar function/purposes but different origins.

Evidence how: not everything is from a common ancestor. Some traits are useful for survivale and reproduction that adaptions and two completely different things appear similar. Traits adapt to fit environments, so things in one environment will have similar traits.

Vestigial Structures - Evidence for Evolution

Body parts that have lost their original function over time.

Shows change over time, proof of adaptations.

Homologous Structures - Evidence for Evolution

Body parts with similar structures that have different uses in different habitats.

Shows how we all diverged from a common ancestor. Our ancestors had traits that divergae over time into different varitation depending on the enviroment and conditions.

Biogeography - Evidence for Evolution

Specices are similar across continents proving they were once one species living on the same continent (pangea). The splitting forced species to change (adapt) depending on temprature changes, terrain changes, competition changes, etc. (Enviroment)

DNA similarities - Evidence for Evolution

Based on DNA sequences we can observe how compitantion vary between species to see how genetically close they are related.

Comparative Embryology - Evidence for Evolution

Supports common ancestory. Human embryos appear to have tails even though babies do not have tails when they are born. What we evolved from do have tails. Embryos look similar across all species.

Artifical selection - Evidence for Evolution

Selectively breeding certain animals for human needs/wants.

Artifical selection can lead to different species (mustard plant ex)

Ring Species - Evidence for Evolution

When a species splis due to geographic barrier (lake ex). On seperate sides of the life, selective pressures can be different, making split species evolve differently. When they meet up again after the barrier the species may be so different that they cant mate anymore. (If natural selection didn’t exist, they should still be able to mate)

Antibiotic resistance - Evidence for Evolution

Bacteria adapts to survive antibiotics.

Binary Fission - Bacteria

Asexual reproduction, offpring only has one parent, making them a genetic clone. Allows for fast reproduction (biggest advantage!!!) but is more vulnerable to mass extinction because of the lack of genetic diversity.

Prokaryotes

tiny, single-celled living organisms that do not have a nucleus, just a nucleiod (where DNA floats around)

Bacteria

Bacteria Mutations

Sometimes bad, cause them to die.

Sometimes good and gives them advantage. When this happens their advatage is immeditely passed on to create a new generation of prokaryotes.

Anitbiotics

Medicines people can take to kill bacteria. But they kill all bacteria, beneficial and pathogents (germs) alike.

Antibiotic resistance

Occurs when a random genetic mutation happens in the individual bacterium, becoming immune to the anitbiotic. (Then it just duplicates, duplicates, duplicates!) The antibiotics kill the weak bacteria, and the new strain will spread. (This is natural selection)