1. Evolution

3. Natural Selection Definition
Process by which a particular gene (or set of genes) is reproduced in succeeding generations more than other genes. (INFLUENCED BY ENVIRONMENT)
Adaption
Any heritable trait that enables an organism to survive through natural selection and reproduce better under prevailing environmental conditions
Variation
The characteristics in individuals that differ from the typical characteristics of others of the same species. Mutation creates variation.
Alan Alda Beak of Finches-Start at 5:45

4. Ecological Niches and Adaptations
Ecological niche-way or life or role in community or ecosystem
Fundamental niche-full range of physical, chemical, biological conditions and resources it can theoretically use up if it could avoid direct competition from other species. *Niches of competing species overlap
Realized niche- Occupying only part of its fundamental niche in a community or ecosystem.
Generalist species-live in many places, eat variety of foods, tolerate wide environmental condition ranges
Specialist species-occupy narrow niches (prone to extinction)
Under which conditions is it better to be a specialist??

5. Is there an organism that you would consider the ultimate generalist?
Can you name an example of a specialist or generalist, especially from our canoe trip?

6. SPOTLIGHT Cockroaches: Nature’s Ultimate Survivors
350 million years old
3,500 different species
Ultimate generalist
Can eat almost anything.
Can live and breed almost anywhere.
Can withstand massive radiation.
Figure 4-A

7. Speciation-What causes new species to arise?
Speciation-two species arise from one
1) Geographic isolation- different groups of the same population of a species become physically isolated from one another for long periods
Barrier can be road, lake, mountains, continental shift, volcano
2) Reproductive isolation-mutations and changes by natural selection occur in gene pools of geographically isolated sexually reproducing species.
If these species get together again, try to mate and cannot, you have 2 different species.

8. Geographic Isolation

9. Geologic Processes, Climate Change, Catastrophes-They shape evolution
Geology
Asteroids (catastrophe)
Caused mass extinctions BUT provided opportunities for evolution by natural selection for existing species. Example of sustainability of biodiversity.
Earthquakes
Separate or isolate populations. Can lead to new species.
Volcanoes
Destroy habitats, wipe out populations, lava can yield soil that provides a habitat
Tectonic plate movement-influences climate and determines where plants and animals can live.
Movement allowed species to move, adapt to new environments and form new species.
Joining continents, species can disperse and adapt to new environments
Moving continents-populations must evolve isolated or become extinct.

10. Biodiversity Hotspots
Let’s share some of our findings from yesterday and review why biodiversity is so important.

11. Importance of Biodiversity
Economy: Provides food, medicine, textiles (cotton)
Ecological services: controlling weeds and pests, pollination of flowers, cleans water, atmospheric regulation, nutrient cycling
Recreational value: provides recreation activities, encourages tourism ($), high aesthetic value
Scientific value: provides organisms in which to study (humans gain knowledge)

12. What have we done to protect the biodiversity on the planet??
Endangered Species Act
1973 signed by President Nixon
Identifies and protects species that are threatened and endangered
Protection of species from:
Poaching, import/export, harassing, harming, trapping, killing, collecting, possessing, selling etc.
Penalizes violators (fine)
Designs protection plants
Reintroduces species
Protecting habitat

13. Extinction: Lights Out
Extinction occurs when the population cannot adapt to changing environmental conditions.
Causes of extinction:
Habitat loss
Overexpoitation (hunting/fishing)
Invasive species
Climate change
The golden toad of Costa Rica’s Monteverde cloud forest has become extinct because of changes in climate.

15. Species and families experiencing mass extinction
Bar width represents relative
number of living species
Millions of
years ago
Era
Period
Extinction
Current extinction crisis caused
by human activities. Many species
are expected to become extinct
within the next 50–100 years.
Quaternary
Today
Cenozoic
Tertiary
Extinction 65
Cretaceous: up to 80% of ruling
reptiles (dinosaurs); many marine
species including many
foraminiferans and mollusks.
Cretaceous
Mesozoic
Jurassic
Extinction
Triassic: 35% of animal families, including many reptiles and marine mollusks.
180
Triassic
Extinction
Permian: 90% of animal families, including over 95% of marine species; many trees, amphibians, most bryozoans and brachiopods, all trilobites.
250
Permian
Carboniferous
Extinction
345
Figure 4.12
Fossils and radioactive dating indicate that five major mass extinctions (indicated by arrows) have taken place over the past 500 million years. Mass extinctions leave many organism roles (niches) unoccupied and create new niches. Each mass extinction has been followed by periods of recovery (represented by the wedge shapes) called adaptive radiations. During these periods, which last 10 million years or longer, new species evolve to fill new or vacated niches. Many scientists say that we are now in the midst of a sixth mass extinction, caused primarily by human activities.
Devonian: 30% of animal families, including agnathan and placoderm fishes and many trilobites.
Devonian
Paleozoic
Silurian
Ordovician
Extinction
500
Ordovician: 50% of animal families, including many trilobites.
Cambrian
Fig. 4-12, p. 93

16. Effects of Humans on Biodiversity
The scientific consensus is that human activities are decreasing the earth’s biodiversity.
Figure 4-13

17. Human Evolution-What was the driving force?
oclimate/climate-and-human-evolution/
Savannah hypothesis vs. Variability Selection Hypothesis

18. Beaks of Finches-Natural Selection Activity
Objective: To determine which “tool” that represent beaks of finches is best suitable to pick up seeds with.
You are working in groups of 3
In notebook: Looking at the objective, devise a problem for this lab.
After reviewing the tools, write a hypothesis for your lab. (make sure it is in an IF-THEN-BECAUSE statement)
Read through the lab and in your groups of 3 and create a data table that records number of trials and seeds taken.
Follow directions in lab. I will be time keeper. Keep your tools to yourself, and do NOT attempt to hurt your classmates (although competition in the wild is another thing…)