Science 2 Flashcards
1
Q
What is the focus of the section on the Earth as a living planet?
A
Exploration of how life is organized from local to global scales
2
Q
What evolutionary processes contribute to the diversity of species on Earth?
A
Genetic variation resulting in environmentally adaptive traits
3
Q
What does community ecology study?
A
How populations of species grow, disperse, and interact with other populations
4
Q
What are ecosystems?
A
Integration of living and nonliving system components in specific geographic areas
5
Q
How are biomes characterized?
A
Variation in global patterns of temperature, sunlight, and rainfall
6
Q
What do global energy and matter cycles refer to?
A
Global biogeochemical cycles on which all ecosystems depend
7
Q
Define biodiversity.
A
Diversity of all the genes, species, and habitats on Earth
8
Q
What is the most common measure of biological diversity?
A
The number of different species in any given place
9
Q
What is genetic diversity?
A
Variety of genes that provide the blueprint for how every individual organism develops
10
Q
How many different genes do humans have approximately?
A
About 30,000 different genes
11
Q
What is the relationship between genotype and phenotype?
A
Phenotype consists of all of an individual’s anatomical, physiological, and behavioral characteristics
12
Q
What is an allele?
A
An alternative form of a gene containing different instructions
13
Q
What is the genotype of an individual with two copies of the B allele?
A
BB or Bb
14
Q
What is a pool of genetic diversity?
A
All the different alleles for a particular trait in a population
15
Q
How can a new allele be produced?
A
Through a mutation, an error made when genetic material is copied
16
Q
What is fitness in evolutionary terms?
A
A measure of the relative viability and fertility of an organism
17
Q
What is adaptation in the context of evolution?
A
The process of becoming most fit or suited for a particular environment
18
Q
What did Charles Darwin’s theory of natural selection explain?
A
Why individuals with certain traits survive and reproduce
19
Q
List the key ideas of Darwin’s theory of natural selection.
A
- Organisms produce more offspring than needed
- Individuals express a range of phenotypes
- Some phenotypes enable better survival in the environment
- More fit individuals have a better chance of reproducing
20
Q
How does environmental change affect species adaptation?
A
Species may die out or adapt through natural selection depending on the pace of change
21
Q
What is a physiological response to environmental change?
A
Short-term adjustments like panting or sweating
22
Q
What happens when species cannot adapt quickly enough to environmental changes?
A
They may die out
23
Q
What is gene flow?
A
Migration of individuals from one population to another, introducing new alleles
24
Q
True or False: All mutations are harmful.
A
False
25
True or False: Genetic diversity is the ultimate source of biodiversity.
True
26
What is gene flow?
The transfer of alleles or genes from one population to another, often through migration.
27
How can gene flow affect a population?
It can introduce new alleles and phenotypes into the population.
28
What is genetic drift?
A random change in allele frequencies in a small population, leading to evolution not associated with selection.
29
What is the bottleneck effect?
A drastic reduction in population size that decreases genetic diversity.
30
What are the consequences of low genetic variation?
* Increased risk of disease * Low fertility
31
What is an example of a species affected by the bottleneck effect?
Cheetah populations, which have low genetic variation and high rates of disease.
32
How long can significant evolutionary changes take?
Many hundreds to thousands of years.
33
What factors influence the pace of evolution by natural selection?
* Rate of environmental change * Amount of genetic variation * Population size
34
What happens when a population's growth rate becomes negative?
The population size will decrease to zero unless it adapts or migrates.
35
What is the fossil record?
The preserved remains of extinct organisms that provide evidence of the history of life on Earth.
36
What is the geologic time scale?
A timeline that divides Earth's history into intervals based on major geological and biological events.
37
What is a mass extinction?
A period when a large number of species go extinct within a relatively short time frame.
38
What is the K-T boundary?
The period 65 million years ago when many species, including dinosaurs, went extinct.
39
What human activities contribute to biodiversity loss?
* Overexploitation * Habitat modification * Introduction of nonnative species
40
What is habitat fragmentation?
The process of breaking up large habitats into smaller, isolated patches.
41
What are the impacts of habitat fragmentation on biodiversity?
* Reduces habitat area * Increases edge habitat * Divides populations
42
What are exotic species?
Species that are introduced to an area where they are not native.
43
How can exotic species impact native ecosystems?
They can outcompete native species for resources and disrupt local ecosystems.
44
What is ecology?
The study of the relationships between organisms and their environment.
45
What factors determine species distribution?
* Abiotic environmental conditions * Availability of resources * Habitats
46
What are abiotic environmental conditions?
Chemical or physical factors that influence survival and growth.
47
What are some abiotic factors affecting terrestrial systems?
* Light availability * Temperature * Precipitation * Soil type * Nutrient quantity
48
What are abiotic environmental conditions?
The chemical or physical factors in the environment that influence survival and growth
49
What major conditions determine species presence in terrestrial systems?
The availability of light, temperature, precipitation, soil type, and nutrient quantity
50
What conditions vary with latitude and elevation?
Temperature, light availability, precipitation, soil type, and nutrient quantity
51
In aquatic systems, what additional conditions play a role besides temperature and solar radiation?
Oxygen levels, salinity, and acidity
52
What is the range of tolerance?
The range within which a given species can exist
53
What happens to individuals under optimal environmental conditions?
They thrive, survive, grow, and reproduce
54
What is the effect of less optimal conditions on reproduction?
Individuals may survive and grow, but not reproduce
55
What are resources in ecology?
Aspects of the environment that individuals use to stay alive, such as food, water, light, and oxygen
56
How do resources differ from environmental conditions?
Resources are consumed and become unavailable to other organisms
57
What is the significance of resource availability at different ecological levels?
Individuals need resources to grow and reproduce, populations need them to avoid extinction, and communities need them to maintain species diversity
58
What is the relationship between resource abundance and species diversity?
There is often little direct correlation between the amount of resources and the number of species
59
What are salt marshes known for?
Producing high levels of biomass and acting as nutrient storage for aquatic habitats
60
What environmental conditions challenge plants in salt marshes?
High and low salt concentrations, low oxygen levels, and toxins from microbial activity
61
What adaptations help salt marsh grasses survive?
Tissues to excrete excess salt and air chambers in roots for oxygen production
62
What are the three general ways populations of different species interact?
Interspecific competition, predation, and mutualism
63
What is interspecific competition?
When individuals of different species share a limiting resource in the same area
64
What is a limiting resource?
A resource that a population depends on, existing in low quantities
65
What principle explains why one species may outcompete another for a limiting resource?
Competitive exclusion
66
What is the concept of niche in ecology?
The role of an organism within a community, including what it does and how it lives
67
What does the competitive exclusion principle state about populations sharing the same niche?
Two populations that fill the same niche cannot coexist
68
How can two populations coexist if they share resources?
By partitioning resources so that their niches do not overlap completely
69
What is an example of interspecific competition among plants?
Wild oat (Avena fatua) competing with agricultural crops
70
What is the broadest definition of predation?
The use of one species as a resource by another species.
71
What are the two other species interactions included in the definition of predation?
* Herbivory
* Parasitism
72
How does predation influence natural selection and evolution?
It establishes how energy flows from one population to another within a community and an ecosystem.
73
What effect do predators have on prey populations?
* They consume them
* They change their behavior
74
What is mutualism?
An interaction that increases the survival probability or reproduction of both species.
75
How do ecologists view mutualism?
As 'reciprocal exploitation' since each species benefits itself.
76
What is the most common type of mutualistic interaction?
The relationship between plants and their pollinators.
77
What is symbiotic mutualism?
An interaction where one animal species pollinates only one plant species.
78
Define an ecological community.
Any assemblage of populations in a particular area or habitat.
79
What does community ecology study?
Groups of populations living in the same area.
80
What is a food web?
A summary of the species that make up a community and the ways they are linked by predator-prey interactions.
81
What are trophic levels?
Feeding positions in a food chain or web.
82
Which organisms occupy the lowest trophic level?
Primary producers such as plants and algae.
83
What type of consumers feed on primary consumers?
Secondary consumers.
84
What percentage of energy from the Sun is transferred to primary producers?
About 1 percent.
85
What is a keystone species?
A species that plays a role in the community that is far more important than its relative abundance would suggest.
86
What are the three types of keystone species?
* Predators
* Ecosystem engineers
* Mutualists
87
How do predators serve as keystone species?
By controlling the population of their prey.
88
What role do ecosystem engineers play?
They create or maintain habitats for other species.
89
What is the definition of an ecosystem?
A spatially explicit unit of the Earth that includes all organisms and abiotic components within its boundaries.
90
What are the three important aspects of an ecosystem?
* The ecosystem's boundary
* The biotic component
* The abiotic component
91
What is a disturbance in an ecosystem?
A process that causes rapid injury or death of organisms and damage to the biotic component.
92
How is resilience defined in the context of ecosystems?
The rate at which an ecosystem returns to its original state after a disturbance.
93
What are biomes?
Major regions of differing vegetation and wildlife types.
94
What two factors have environmental scientists correlated with terrestrial biomes?
* Mean annual temperature
* Mean annual precipitation
95
What are the two major aquatic systems?
Freshwater and marine
96
How are freshwater systems categorized?
Flowing (rivers and streams) and standing (ponds and lakes)
97
What community is found at the bottom of rivers and streams?
Benthic community
98
What is the primary energy producer in lakes and ponds?
Phytoplankton
99
Who feeds on phytoplankton in lake and pond ecosystems?
Zooplankton
100
What are thermoclines?
Abrupt changes in the temperature of water with depth
101
What percentage of the Earth is covered by the ocean?
71 percent
102
What are the main factors influencing marine ecosystems?
Light, nutrients, depth, currents, and shoreline characteristics
103
At what depths does peak species diversity in oceans generally occur?
2,000−3,000 meters
104
What are upwellings?
Coastal and open ocean areas where nutrient-rich water rises to the surface
105
What are wetlands?
Transitional areas between terrestrial and aquatic environments
106
What are the three broad types of wetlands?
* Marine wetland (intertidal region)
* Estuarine wetland (where salt and fresh water mix)
* Freshwater wetlands
107
What is the primary driver of biogeochemical cycles on Earth?
Water cycle
108
What is evapotranspiration?
The combination of evaporation and transpiration
109
What are the four processes that run the carbon cycle?
* Photosynthesis
* Respiration
* Decomposition
* Combustion
110
What is carbon fixation?
The process of converting carbon dioxide into plant material
111
What are fossil fuels?
Compounds formed from organic matter that gets buried and fossilized
112
What is denitrification?
The conversion of nitrate to nitrous oxide gas
113
What is the significance of nitrogen in the nitrogen cycle?
It is critical for life and a limiting element for plants
114
What is ammonification?
The conversion of organic matter to ammonium
115
What is nitrification?
The conversion of ammonium to nitrite and then to nitrate
116
What is biodiversity?
The diversity of all genes, species, and habitats on Earth
117
What does genetic diversity derive from?
Varying combinations of alleles
118
What is natural selection?
The process where certain phenotypes enable individuals to survive and reproduce
119
What is the current extinction rate commonly measured by?
Estimating habitat loss
120
What are the three general ways species interact with each other?
* Interspecific competition
* Predation
* Mutualism
121
What is a biological community?
The assemblage of all populations in a particular area or habitat
122
What is community ecology?
The study of how populations interact within a biological community
123
What is a biological community?
The assemblage of all populations in a particular area or habitat.
124
What is community ecology?
The study of how populations interact within a biological community.
125
What are the three general ways species interact?
* Interspecific competition
* Predation
* Mutualism
126
What is a food web?
The complex flow of energy from photosynthesizing producers to herbivores and then to predators.
127
What is the role of keystone species in a community?
The loss of a keystone species can lead to the damage or extinction of the entire community.
128
What are ecosystems?
Specific places on Earth made up of interacting living and nonliving components.
129
What drives the interaction of an ecosystem’s components?
Global biogeochemical cycles of elements and nutrients.
130
What causes variation in the biotic components of a region?
Changes in temperature and moisture.
131
What are the ten major types of terrestrial biomes correlated with?
A region’s mean annual temperature and mean annual precipitation.
132
What are the two broad divisions of water systems?
* Fresh water
* Marine environments
133
What are the critical cycles in ecosystems?
* Water cycle
* Carbon cycle
* Nitrogen cycle
134
What is the water cycle?
The movement of water through the atmosphere and over the surface of the Earth.
135
What is the carbon cycle?
The movement of carbon compounds through the atmosphere, oceans, and living organisms.
136
How is carbon released back into the atmosphere?
Via respiration and decomposition.
137
What is the nitrogen cycle?
A set of processes in which nitrogen is converted into different forms as it cycles through the environment.
138
What drives the nitrogen cycle?
Microorganism fixation of atmospheric nitrogen and its conversion into a biologically useful form.
139
Fill in the blank: The building blocks of life include water, carbon and _______.
nitrogen
