Adaptation – A trait that allows a species to survive more ......Adaptation • Adaptation – A trait that allows a species to survive more easily and reproduce. Adaptation of Beaks

Adaptation

• Adaptation – A trait that allows a species to survive more easily and reproduce.

Adaptation of Beaks

Adaptations of Feet

Modern humans (Homo sapiens) appear about 2 seconds before midnight

Recorded human history begins 1/4 second before midnight

Origin of life (3.6–3.8 billion years ago)

Origin of Life

EVOLUTION• Evolution - Inheritance of specific genetic

traits that controls adaptations, giving a species an advantage in an environment.

Evidence of Evolution

• Physical Similarities ❖ Most animals have

similar bones in their limbs (fins, arms, wings)

• Comparing DNA • Vestigial Structures

❖ Still exist in the body but are no longer needed

❖ Examples....

Natural Selection

Natural Selection

More...

Natural Selection

• Natural Selection - Describes process where better competitors survive and reproduce more successfully. (It is the engine that drives evolution).

• Caused by: ❖ Random mutations – Changes in DNA are

usually bad, but can be beneficial. ❖ Selective pressure – Limited resources mean

only the best competitors survive. ❖ Sexual selection – Females choose a mate

based on certain characteristics.

Factors Exerting Selective Pressure

• Physiological stress due to inappropriate levels of a critical environmental factor. ❖ Moisture, Light, pH

• Predation ❖ Organism is hunted and killed by another ❖ Includes parasites, bacteria, viruses

• Competition ❖ Other organisms attempting to use same

resources • Luck

Artificial Selection

• The selective breeding of organisms by humans for specific characteristics.

Speciation• Given enough time, enough mutations occur

that a new species develops from an old one. ❖ When are two groups considered a

different species? - They cannot (or will not) interbreed to

produce healthy, fertile offspring.

- The original population of these squirrels was separated by formation of Grand Canyon. Now if brought together they cannot breed.

Types of Speciation

• Divergent - Separation of one species into new species.

Types of Speciation

• Convergent - Unrelated organisms evolve to look and act alike. • Not related • Caused by living in

similar environments

Coevolution

The process of two species evolving in response to long-term interactions with each other.

Same or Different Species?

Animal Hybrids or New Species?

• More examples…

domestic canary/goldfinch

jaguar/lion

zebra/donkey

• Crayfish ❖ a.k.a. Crawdad ❖ a.k.a. Spiny lobster ❖ a.k.a. Yabby ❖ a.k.a. Crawfish ❖ a.k.a. Creekcrab ❖ a.k.a. Mudbug

• We need an internationally accepted name!

The Taxonomic Naming System

Scientific Naming System

• Based on the classification system. • Includes the organism’s genus and species

name. ❖ Genus is capitalized ❖ Species is lower case ❖ The scientific name is written in italics

• Scientific name of the crayfish: Procambarus clarkii

The Taxonomic Naming System

• Divides organisms into different levels of organization.

❖ Kingdom ❖ Phylum ❖ Class ❖ Order ❖ Family ❖ Genus ❖ Species

• The more levels two organisms have in common, the more related.

Know YOUR Classification

How related are they?

Canis lupus

European Wolf

Canis lupus familiaris

Domesticated dog

For years the domestic dog was classified as a species (Canis familiars). However, DNA analysis revealed domestic dogs evolved from wolves. This led scientists to reclassify dogs as a subspecies of the wolf rather than a separate species.

How related are they?

Ara ararauna

parrot (blue and yellow macaw)Chlorurus microrhinos

parrot fish

Phylogenetic Tree• Also known as a “tree of life”. • Organisms are grouped and classified based

on three characteristics: ❖ Physical characteristics ❖ DNA ❖ Behavioural characteristics

- Mating rituals, territorial, aggression, etc. • The more of these characteristics two

organisms have in common, the more closely related they are according to evolution.

Phylogenetic Tree of Life

From left to right: 1. Orangutan 2. Gorilla 3. Human 4. Chimpanzee 5. Bonobo