1. Unit 4
Chapters 4 and 5

3. ecological niche- species way of life in a community
The American Alligator-
ecological niche- species way of life in a community
What job does it do or role does it fulfill?
The Alligator is a: Keystone species- A species in an ecosystem that plays a central role in the health of that ecosystem, and whose removal may cause the collapse of the ecosystem that’s the niche of the alligator

4. Biodiversity or Biological diversity
The variety of the Earth’s species, the genes they contain, the ecosystems in which they live, and the ecosystem processes such as energy flow and nutrient cycling that sustain all life

6. Why is biodiversity important?
Food
Wood
Fibers
Energy
Medicines
Preserving air, water, and fertile soil

7. Natural selection
Charles Darwin
Alfred Wallace

8. Observations that were the basis of the proposal for the concept of evolution
Organisms struggle
Some individuals have advantages that help them survive
The ones that survive, pass these traits down to offspring
Natural selection
A change in the genetic characteristics of a population from one generation to another is biological evolution

10. Genetic variability is the first step
Occur through mutations
Only mutations in reproductive cells are passed down
Mutagens are external agents that cause mutations, but mutations can occur randomly(chemicals, UV light, radioactivity, Xrays)
Adaptation or adaptive trait- any heritable trait that enables an individual to survive
In order for natural selection to occur, a trait must be heritable, meaning that it can be passed down from one generation to another. The trait must also lead to differential reproduction.

11. Genetic resistance occurs when some members of a population are genetically able to overcome chemicals designed to kill it. Over time, the genes that make them resistant to the chemicals become more common in the population, until that population is unable to be killed by the chemical.

12. Summary of biological evolution
Genes mutate, individuals are selected, and populations evolve that are better adapted to survive and reproduce under existing environmental conditions.

13. Possible futures
Adapt
Migrate
Become extinct

14. Adaptations of humans that have made them successful
Strong opposable thumbs
Walk upright
Complex brain

15. Limits to natural selection
Adaptations only occur for traits already present in a populations gene pool.
Even if a beneficial heritable trait is present in a population, the population's ability to adapt may be limited by reproductive capacity

16. Common myths
Survival of the fittest- does not mean survival of the strongest-
Organisms do not develop traits because they need or want them
Grand plan of nature no such thing

17. Effects of plate tectonics
1. Locations of continents influences climate which helps determine where plants and animals can live
2. The movement of continents has allowed species to move, adapt and form new species through natural selection

19. Speciation- two most common mechanisms
Geographic isolation
Reproductive isolation

21. Extinction is forever Golden toad- endemic to costa rica
Extinction due to climate change

23. Background and mass extinction
Background rate of extinction- normal low rate of extinction throughout history- 1 to 5 species per million species
Mass extinction- loss of many species in a short amount of time-25%-70%
5 mass extinctions have occurred in the last 500 million years.

24. Species richness- number of different species
Species rich ecosystems have a lot of different species, but just a few individuals per species

25. Species evenness- abundance of individuals of each species

26. General pattern based on geographical location
higher diversity in tropics
Most diversity in rainforest, coral reefs, the ocean bottom zone and large tropical lakes
Species rich ecosystems are more productive and stable due to higher numbers of different producers with more feeding relationships

27. Each species has a distinct role to play in in an ecosystem

28. Generalist vs. Specialist species
A generalist species has a broad niche(live in many places, eat a variety of food, tolerate a wide range of conditions)(Ex. Flies, roaches, mice, rats, white-tailed deer, raccoons, and humans)
A specialist species has a narrow niche(one types of habitat, one or few types of food)(tiger salamanders, giant pandas)

30. Which is better? It depends, When conditions are stable, specialists are better off. When conditions are rapidly changing, generalists do better

32. Cockroaches: nature’s ultimate survivor
3,500 species, eat almost anything, live almost anywhere, avoid predators, High reproductive rates, quick genetic resistance,

33. Non-native species
A.K.A.- invasive, alien, exotic
They can spread rapidly if they do not have predators and diseases they faced before, or they may be able to out-compete native species

34. Indicator species are Bbiological smoke alarms
They provide early warnings of damage to a community or an ecosystem.

35. factors that can affect frogs and other amphibians at various points in their life cycles
Habitat loss and fragmentation
Prolonged drought
Pollution
Increases in UV radiation
Parasites
Viral and fungal diseases
Climate change
Overhunting
Natural immigration of, or introduction of nonnative predators and competitors

36. Why should we care about amphibians?
Sensitive biological indicators
Important ecological roles in biological communities
Genetic storehouse of pharmaceutical products waiting to be discovered.

37. Keystone species
Pollination
Top predator

38. Foundation species- Examples- elephants, beavers
What’s the difference between a keystone and a foundation species?
Foundation species help to create habitats and ecosystems
Keystone species do this and more

40. Illustrates the principle of population control
Ch 5 notes
Sea otters generate millions of dollars in tourism.
Keystone species that helps maintain kelp forests to maintain biodiversity.
5 types of species interactions-
Interspecific competition
Predation
Parasitism
Mutualism
Commensalism
Illustrates the principle of population control

42. Competitive exclusion principle
No two species can occupy exactly the same ecological niche for very long
Methods of capturing prey
Carnivores- pursuit and ambush
Camouflage
Chemical warfare

43. How prey avoid predators
Speed, developed sense of sight or smell, protective shells, thick bark, spines, thorns, camouflage, bright coloring, chemical warfare, warning coloration,

44. E.O. Wilson
If it’s small and strikingly beautiful, it’s probably poisonous.
If it’s strikingly beautiful and easy to catch, it’s probably deadly.

46. Coevolution
Predators and prey constantly exert intense natural selection pressures on each other.

47. Parasitism- one benefits the other is harmed

48. parasitism

49. Mutualism- both benefit

50. mutualism

51. Commensalism- one benefits, the other is not helped or harmed

52. Reducing niche overlap
Resource partitioning- when species competing for similar scarce resources evolve specialized traits that allow them to use shared resources at different times, in different ways, or in different places.

56. Population distribution
Even
Random
Clumped
Clumped is the most common because resources are often found in patches

57. Population change
Population change = (births + immigrations) – (deaths + emmigration)
Intrinsic rate of increase- reproduce early in life, have short generation times, can reproduce many times, and have many offspring each time
When a population exceeds carrying capacity, the population can crash.
Overshoot occurs because of reproductive lag time.

60. K- selected and r-selected
r-selected species have a capacity for a high rate of population increase, they produce many offspring to try to overcome huge losses when offspring are young (they have boom and bust cycles of population growth)
K-selected- long life spans, reproduce later in life, small number of offspring, cared for by parents

61. Genetic factors that play a role in loss of genetic diversity
Founder effect- occurs when a few individuals in a population colonize a new habitat that is geographically isolated from other members of the population.
Demographic bottleneck- when only a few individuals survive a catastrophe such as a fire or hurricane

62. Genetic drift- random changes in the gene frequencies in a population that can lead to unequal reproductive success
Inbreeding- when individuals in a small population mate with one another

63. Density dependent population controls
Competition for resources, disease, predation, parasitism

64. Density independent
Floods, fire, hurricanes, pollution, drought, habitat destruction

65. Four general patterns of variations in population size?
1. Stable- fluctuates near carrying capacity
2. Irruptive- grows to a high peak and then crash to a more stable lower level
3. Cyclic(boom and bust)- populations rise and fall every so many years
4. Irregular- no recurring pattern

66. Ecological succession
The gradual change in species composition in a given area.
Primary succession- happens where no previous ecosystem has existed (exposed rock from a receding glacier)
Secondary succession occurs where an ecosystem has previously existed. For example, abandoned farms, forests after a fire, etc.

68. Inertia or persistence- the ability of a living system to survive moderate disturbances.

69. resilience
The ability of a living system to be restored after a period of moderate disturbance

70. Tipping point
Ecosystems and global systems have limits to the stresses they can take. The level beyond which any additional stress will cause an abrupt and unpredictable change