adaptation – a trait that allows a species to survive more ......adaptation • adaptation – a...
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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
• 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