- Slides: 32
Same species? Rabbit Horse Different species
Same species? Chihuaha and Great Dane Same species, different breeds
Same species? Ostrich and Hummingbird Different species��
Same species? Eastern Meadowlark Western Meadowlark Different species
Same species? Pheidole barbata ants Same species, different jobs
Same species? Happy Face Spiders Same species
A species is usually defined as: A group of similar organisms that can mate and produce fertile offspring.
What about hybrids?
Most bacteria reproduce asexually
Extinct species can’t mate
Animals separated by geography don’t mate
Another way to define a species Branching tree (phylogenetic tree)
Comparing nitrogen base sequences in DNA
Comparing developing embryos of different organisms
Comparing body structures (homologous structures)
How do new species form? Evolution: gradual change in a species’ traits over time. Natural selection: individuals who are better suited to the environment are more likely to survive and reproduce.
In order for new species to evolve: Groups within the population need to stop exchanging genes (mating) so that they can evolve separately.
Why might two groups of the same organism stop mating?
Separated geographically Continental drift
Placental mammals and marsupials
Separated geographically Different environments on each side of the road
Separated by lifestyle? Apple flies and Hawthorn flies
Changes in environment
Imagine that 10, 000 years in the future there is a new human-like species that is 2 feet tall, covered in hair, and has a beak. What might have happened between now and then to cause this new species to evolve?