1. Human Activities and Biodiversity

2. Background Information
Today, as in the past, people have a huge impact on biodiversity. Many recent extinctions have been caused by human actions.
Scientists estimate that hundreds of thousands of species are at risk of extinction today.
Recent measurements show that current rates of extinction are faster than any recorded in human history.

3. Background Information
Some scientists think such evidence means the earth is undergoing a sixth mass extinction.
Since Earth’s biodiversity provides so many valuable goods and services to humans, and biodiversity is important for the health and well-being of ecosystems, these extinctions will likely have adverse consequences for humans’ social and economic well-being.

4. Background Information
Biodiversity ensures that ecosystems will be sustained into the future in part through evolution.

5. Expected vs. Observed Extinctions

6. Biodiversity
The assortment of species on earth within and between ecosystems and the variation in the genetic composition of a species. Same as biological diversity.

7. Ecosystem Diversity
Variation in biodiversity within and between ecosystems on earth.

8. Genetic Diversity
The variation in the genes within a population of organisms.

9. Species Diversity
The number of species that exist in an area.

10. Taxa
Level of classification, such as genus or species.

11. Status of Living and Extinct Taxa
Mammals: Nearly 1/4 (22%) is globally threatened or extinct.
Amphibians: Nearly 1/3 (31%) is globally threatened or extinct.
Birds: 1/7 (14%) is globally threatened or extinct.

12. Exit Slip
What do you think are some of the largest contributing factors of how human activity effects Biodiversity?

13. Activity 2
Now Complete Activity 2, Human activities and Biodiversity from your SGI Biology textbook.

14. Geologic Time

15. Geologic Timeline

16. Background Information
Scientists have divided the earth’s history into a series of time periods referred to as the geologic time scale.
The boundaries of the time periods are defined by the first appearance or the disappearance of certain fossils in the record, and thus vary greatly in length.

17. Background Information
Scientists estimated the date range for each time period using radiometric dating technology.
Radiometric Dating Video:
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As new fossils are discovered and radiometric dating technologies continue to improve, these estimated dates are likely to be adjusted.

18. Earth’s Early Conditions
Inhospitable living Conditions
Volcanic Activity
Lots of molten lava
Earth was VERY hot (How hot was it?)
No atmosphere initially
No water
Lots of ultraviolet radiation (no ozone layer)

19. Earth’s Early Atmosphere

20. Earth’s Early Conditions
Volcanic gasses given off:
H2 -- hydrogen
N2 -- nitrogen
H2 O vapor
CO and C02
NH 4 -- ammonia
CH4 -- methane

21. Changes in Earth’s History
Weather began after the atmosphere built up from volcanic gasses.
Torrential rains from water vapor built up
Filled up Earths basins to become bodies of water
Caused erosion

22. Changes in Earth’s History
Plate tectonics
(Pangaea – all continents)
Supercontinent began to break apart and move around Earth
Mountain formation
Earth cooled down
Several Ice ages occurred

23. Earth’s Current Conditions
Atmosphere
N2 ≈ 70%
O2 ≈ 21%
Misc. ≈ 9%
Water 70% of surface
Land 30% of surface

24. Earth’s Current Conditions
Weather and climate varies around the world according to latitude.
Earthquakes and volcanoes occur occasionally
Lots of Life (great biodiversity)

25. Important Dates 15 Billion years ago (BYA) – Universe formed
4.6 BYA – Earth formed
3.9 BYA Earth cooled and oceans formed
3.5 BYA – first life appeared

26. Eras of Earth’s History
Precambrian ( 3.4 BYA)
- 87% of Earths history
- oldest evidence of life found in Precambrian rock
Prokaryotic → no nucleus
Eukaryotic → have a nucleus
By the end of this era, the oceans were filled with multicellular organisms like algae, sponges and jellyfish.

27. Eras in Earth’s History
Paleozoic
- Lasted until 248 million years ago (MYA)
During the Cambrian Period there was a great increase in biodiversity
(E.g. - worms, echinoderms, arthropods, fish, ferns, reptiles, amphibians)
Mass extinction at the end of the Paleozoic.
90% of marine spp. And 70% of land spp. gone forever.

28. Eras in Earth’s History
Mesozoic
Divided into 3 periods:
Triassic – 1st mammals (they were tiny then) and 1st dinosaurs
Jurassic – the “age of dinosaurs”
Cretaceous – more mammals and flowering plants (E.g. – oak, fig, and elm trees)

29. Eras in Earth’s History
Cenozoic
Began 66 MYA
This is the era in which we live
Primates evolved → we belong to this group of mammals
Modern human spp. Evolved about 200,000 YA

30. Over 90% of the species that have lived on Earth are now extinct → consider how biodiverse the Earth would be had they not died off…

31. Geologic time
A vast timescale of billions of years, related to the geological and evolutionary history of the earth.

32. All of the periods of the earth’s history.
Geologic timeline
All of the periods of the earth’s history.

33. Exit Slip
Considering all of the major geologic events that have occurred on planet earth, is human activity capable of creating another major geologic event on Earth’s timeline?

34. Now Complete Activity 3 from the Evolution Unit in our Biology Textbooks

35. Let’s start with the first set of slides1.
TRANSITION HEADLINE
Let’s start with the first set of slides

36. Let’s start with the first set of slides1.
TRANSITION HEADLINE
Let’s start with the first set of slides