species change over time lamarckdarwin. who thought this? there is variation within a species darwin...
TRANSCRIPT
Who thought this? There is VARIATION within a
species DARWIN
Organisms can make a change to themselves and pass that onto their offspring LAMARCK
Change within a population, not an individual DARWIN
Natural Selection DARWIN
Acquired Characteristics LAMARCK
Organisms change over time. BOTH
Species cannot go extinct Lamarck
Whose idea is still believed by the scientific community today Darwin
Review of Important Terms to Know
Traits-characteristics of a species that are passed from parent to offspring.
Offspring- the scientific name for “babies” of an organism
SpeciesSpecies- a group
similar organisms that can mate with each other and produce fertile offspring
Fertile- the ability to reproduce
~8.7 Million Species Worldwide!
Animals: 7.77 million
Fungi: 0.61 million
Plants: 0.30 million
Protozoa: 0.04 million
Chromists: 0.03 million
VariationVariation- any
inherited difference between members of the same species
Ex: albino squirrel, the ability for baby turtles to swim faster, a longer neck, wider nostrils, thicker fur…
Forsten’s Tortoise
What Causes Variation? SEXUAL REPRODUCTION
Variations result from permanent changes in an organism’s genes.
The permanent changes in the genes are called MUTATIONS.
Mutations…Good or Bad???
Mutations can be either beneficial, harmful or neutral.
Some gene changes produce LARGE variations. Ex: Albino squirrel
Some gene changes produce small variations Ex: shape of human
hairlines
“People don't realize it, but everyone has about 60 genetic mutations in their body at any given time. (Tudge, Colin)”
King Cheetah Pattern Mutation “A genetic mutation
changes a spotted cheetah pattern to a striped king cheetah pattern.”
Adaptation Adaptation- a variation
(or trait) that helps an organism survive & reproduce
Adaptations can be behavioral or physical.
AdaptationsBEHAVIORAL
The way an organism acts or behaves
Migration Hibernation Communication Mating dances
PHYSICAL
Body structures
Camouflage Shapes of beaks Fur Blubber Color or Markings Webbed-feet Body coverings
Darwin’s Theory of Natural Selection
Natural Selection- individuals that are better adapted to their environment are more likely to survive & reproduce than other members of the same species
Also known as “Survival of the Fittest”
Competition2) Competition-
individuals compete for food, nesting sites, territory, & other resources that affect their ability to reproduce
Variation3) Variations- a
difference between members of same species that may help it survive and reproduce
Some are born with an advantage over the others!
Ex: beak shape, eyesight, height, speed…
Selection 4) Selection- over time,
the environment “selects” organisms w/ helpful traits to be parents of next generation
Ex: Just as the changing forest affected the peppered moths.
.
WRAP UP
Over a long period of time, natural selection can lead to the evolving of a new species. Helpful variations remain & unfavorable ones disappear
Factors that Affect Natural Selection
1) Overproduction- producing more offspring than can survive
2) Competition- offspring compete for food & other resources
3) Variations- a difference between members of same species that may help it survive
4) Selection- over time, the environment “selects” organisms w/ helpful traits to be parents of next generation
Do Now: Bear Trio! In your journal answer
the following questions.
What differences do you notice among the three bears?
What did Darwin call these differences?
What causes these differences among organisms?