back to macroevolution n.
Skip this Video
Download Presentation
Back to MACROevolution

Loading in 2 Seconds...

play fullscreen
1 / 14

Back to MACROevolution - PowerPoint PPT Presentation

  • Uploaded on

Back to MACROevolution. What does it mean again?. large-scale evolutionary changes including the formation of new species & taxa . happens over a much longer period of time (centuries, millenia ). Recall from Grade 9 Ecology. A population is.

I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
Download Presentation

PowerPoint Slideshow about 'Back to MACROevolution' - lucie

Download Now An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.

- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
back to macroevolution
Back to MACROevolution

What does it mean again?

  • large-scale evolutionary changes including the formation of new species & taxa.
  • happens over a much longer period of time (centuries, millenia).
recall from grade 9 ecology
Recall from Grade 9 Ecology....

A population is...

a group of the same species of living things (i.e. All the people on planet Earth).

A community is...

groups of different species of living things in an area (i.e. All the frogs, snakes, fish, & lily pads in a pond ecosystem).

development vs evolution
Development vs. Evolution

What’s the difference?

Development refers to changes that happen to an organism as it progresses through its life cycle.

Evolution refers to changes that occur in an entire population over a very long period of time.

what is a species
What is a “species”???

A group of individuals that actually or potentially interbreed in natureto produce viable or fertile offspring.

These happy face spiders look different, but since they can interbreed, they are considered the same species: Theridiongrallator.



Result of male tiger and female lion mating in captivity. Offspring are infertile.



Result of male lion and female tiger mating in captivity. Offspring are infertile.

  • The formation of a new species
  • The original species must to become reproductively isolated from the rest of the population (reproductive isolation)
reproductive isolation
Reproductive Isolation
  • Members of two populations cannot interbreed and produce fertile offspring
  • Two types:
    • pre-zygotic mechanisms
    • post-zygotic mechanisms
pre zygotic mechanisms
Pre-zygotic Mechanisms

prevents different species from mating and fertilizing

post zygotic mechanisms
Post-zygotic Mechanisms

prevents maturation and reproduction of interspecies offspring

modes of speciation
Modes of Speciation

Allopatric Speciation: Evolution of population into two different species caused by geographic isolation (e.g. Rivers, canyons, mountains, large bodies of water)

The barrier prevents species from interbreeding, which causes them to slowly change until they become so different that they are reproductively isolated

modes of speciation1
Modes of Speciation

Sympatric Speciation: Evolution of populations into new species within the same geographical area

A significant mutation happens to work out, resulting in reproductive isolation of the two populations

Example: hawthorn fly vs. Apple maggot flies in North America


Note: Over time, the genetic differences between the two populations are enough that they can then lead to speciation.


Answer the following question: What type of speciation do human built structures (i.e. Roads) likely cause?

2. Theories of Evolution Assignment – Due Monday, Dec 5/11