Title: Classify the following: Trout, catfish, frog, snake, whale, human, cardinal, turtle, salamander, shark, dolphin, bat, blue jay,
1Classify the following Trout, catfish, frog,
snake, whale, human, cardinal, turtle,
salamander, shark, dolphin, bat, blue jay,
2- Did you group them by movement?
-
- SWIMMERS FLIERS UPRIGHT
-
- Trout cardinal Human
- Catfish bat
- Whale blue jay
- Shark
- dolphin
- HOP/CRAWL/SLITHER
- frog turtle
- snake salamander
-
-
3- Or by
- FISH AMPHIBIANS REPTILES
- trout frog snake
- catfish salamander turtle
- shark
- BIRDS MAMMALS
-
- blue jay whale bat
- cardinal dolphin
- human
-
4Evidence for evolution
- Scientists compare these things to determine the
evolutionary relationships among organisms. - 1. body structures
- 2. development before birth
- 3. DNA sequences
51. SIMILARITIES IN BODY STRUCTURE
- An organisms body structure is its basic body
plan (ex. How its bones are arranged.) - The 5 classes of vertebrates (fish, amphibians,
reptiles, birds and mammals) all have a similar
body structure Internal skeleton w/a backbone.
6HOMOLOGOUS STRUCTURES similarities in structure
inherited from an early common ancestor
72. Similarities in Early Development
- Scientists can also make inferences about
evolutionary relationships by comparing the early
(embryonic) development of different organisms.
8rat
chicken
turtle
93. Similarities in DNA
- Scientists infer that the species inherited many
of the same genes from a common ancestor. - Genes are made of DNA. By comparing the sequence
of nitrogen bases in the DNA of different
species, scientists can infer how closely related
the species are. The more similar the sequences,
the more closely related the species are.
10- Because of its appearance, the tiny elephant
shrew was once thought to be closely related to
mice. DNA analysis shows that they are much more
closely related to elephants! Ya never know!!
11Combining evidence
- Scientists have combined evidence from fossils,
body structures, and early development, and DNA
and protein sequences to determine the
evolutionary relationships among species.
12- An example of how scientists combined evidence
from different sources is shown in the branching
tree. A branching tree is a diagram that shows
how scientists think different groups of
organisms are related.
13Below image from Prentice Hall Life Science.
Most recent species at top of tree
Time moves from the past at the bottom to
present time at the top to
ForksWhere species began to evolve away from
their common ancestor
Common ancestor at bottom of tree
14Natural Selection
- The process by which individuals that are better
adapted to their environment are more likely to
survive and reproduce than other members of the
same species.
154 Parts of natural selection
- 1-overproduction
- 2-competition/struggle to survive
- 3-variations
- 4-selection/successful reproduction
161. Overproduction
- Most species produce far more off spring than can
possibly survive - Often so many are produced that there are not
enough resources for them all. - Ex Sea turtles
17What would happen if all the young sea turtles
lived?
- Sea turtles lay 100s of eggsif they all
survived, the ocean would be full of turtles.
18Darwin knew better
192. Competition
- Offspring must compete with each other to
survive. - Competition does not necessarily mean physical
fighting. - It is usually indirect
20For example,
- Some baby turtles
- May not be able to find enough to eat.
21Variations
- Members of a species differ from each other in
many of their traits. - Any difference in between individuals of the same
species is called variation.
22For example
- Some turtles
- are able to swim
- faster than others
- To escape from
- predators.
23- Remember you dont have to be faster than the
predator, you just have to be faster than the
other prey!
24Selection
- Over a long period of time, natural selection can
lead to evolution. - Helpful variations gradually accumulate in a
species, while unfavorable ones disappear.
25For example
- A new faster predator moves into the turtles
habitat.
26Perhaps a faster breed of shark
27- The turtles that are able to swim faster would be
more likely to escape from the new predator.
28- The faster turtles would be more likely to
survive and reproduce. Over time, more turtles in
the species would have the fast-swimmer trait.
29Genes
- What role do genes have in evolution?
- Variations can occur due to mutations in genes or
from the shuffling of alleles during meiosis. - Therefore, only traits that are inherited are
acted upon by natural selection
30How are new species formed?
- A new species might form when a group of
individuals remains separated form the rest of
its species long enough to evolve different
traits. - This is called isolation or complete separation.
31Continental drift
- Millions of years ago on the super continent
Pangaea, organisms could travel from one part of
the continent to another.
32- Pangaea gradually split apart over millions of
years in a process called continental drift. - As this separation happened, species became
isolated from one another and began to evolve
independently.
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