Unit 3 Exam Study Guide Flashcards
What is biodiversity?
It refers to the diversity of species on Earth.
What is a species?
A species is a type of organism. Often described as individuals that can reproduce (exchange genetic information) and produce fertile offspring.
_________ of the same _______ look alike because they share a genetic history, but there is a _________.
Individuals, species, variation
Members of different _______ can occasionally ________ and produce ______.
species, interbreed, hybrids
Species can be grouped into larger groups called _____.
taxa
Overall most groups of species are _______ but some more than others.
declining
What are five ways humans are threatening other species?
- Habitat loss (reduction in quality of habitat where species live)
- Invasive species (species not native to an environment can compete with native species for resources)
- Pollution
- Overharvesting (unsustainable hunting, poaching, or harvesting)
- Climate change
Human activities are having an impact on ________.
biodiversity
What is species diversity?
One way to measure species diversity is to count the number of species in an area. This is called species diversity.
What is species richness?
Species diversity is the variety of different species in a particulate place.
Scientists estimate that there are between _________ and ________ species on Earth.
5.3 million, 1 trillion
Only about _______ species have been named.
2 million
__________ varies in different parts of the world
Biodiversity
What are hotspots?
Hotspots are the most biologically diverse and threatened areas on Earth.
Who manages hotspots?
Because hotspots are important for conservation, many are managed/sustained by indigenous communities.
Hotspots cover ___ of Earth’s surface but have over ___ of species.
<1.5%, 30%
_________ are biodiversity hotspots.
Tropical rainforests
Every degree of warming will increase the impacts of ________ on other species.
climate change
What are endemic species?
Endemic species are species that are found in only one area on Earth. Ex. Golden toad
Why are endemic species prone to extinction?
If they disappear from their one area, they will go extinct because they don’t exist anywhere else. (Typically smaller populations).
What are specialist species?
Specialist species make their living in a particular way. Ex. Giant panda, Green sea turtle, Yucca
Why are specialist species prone to extinction?
They can only eat one food or live at a certain temperature or reproduce in a particular place. They don’t adapt easily to changes in the environment.
What are generalist species?
Generalist species tolerate a large range of environmental conditions. Ex. House sparrow, Raccoon
Why are generalist species less prone to extinction?
They thrive around humans: they eat almost everything and adapt to changes in environment.
What are organisms with low reproduction?
They are organisms that take a while to reach sexual maturity. When they reproduce, they have a few offspring at a time. Ex. Sand tiger shark, N. white rhino
What are organisms with high reproductive output?
They reproduce quickly and have many offspring in a litter. Sometimes, they reproduce many times in the same year. Ex. Rat, cockroach
What are examples of animals that have a good relationship with humans?
Swans or house cats
What are examples of organisms that are heavily hunted or in conflict with humans?
Sea otters and elephant ivory
What are seven examples of the types of organisms that are generally doing well:
- Generalists
- Adapt to disturbances
- Have large populations
- Found in many places
- Don’t have predators
- Reproduce quickly
- Benefit from humans
What are five examples of types of organisms that are at risk of extinction?
- Specialists
- Have small populations
- Endemic to particular environments
- Do not reproduce fast
- Sensitive to environmental change
What is extinction?
Extinction means that a species is completely gone. Extinction is a normal process.
What is baseline extinction?
It’s the “normal” ongoing extinction rate.
Throughout the history of life on Earth, new species have ________ and others gone ______.
evolved, extinct
The number of species at any one time is the _______ between ________ (formation of new species) and __________.
balance, speciation, extinction
Occasionally many _____ go ______ at once.
species, extinct
What is a mass extinction?
These extinctions happen across taxa and over a relatively short period of time.
Healthy, intact ecosystems provide us with _______ that sustain and fulfill life.
ecosystem services
What are six examples of ecosystem services?
- Source of food/oxygen
- Clean water
- Protection from extreme weather/flooding
- Pollination and pest control
- Source of medical compounds
- Psychological health
The field of _____________ is focused on protecting ________ and ______ through research and by _________________________.
conservation biology, habitats and species, working with local governments and communities
Suburban lawns are an example of ecological _______.
dead space
Insect populations have declined by _____ in the last few decades due to pesticide use, habitat loss, and climate change.
49%
What is the connection between native plants and insects?
Insects are often specialists and show a preference for native plant species. Insects are food and pollinators for so many other native species.
True or false: Biodiversity is not the only source under threat.
True
What are four important factors of water?
- Human body is 70% water.
- Water fills cells giving them shape.
- Many substances dissolve in water (the content of our cells/blood)
- Many chemical reactions require water (Photosynthesis: CO2+Water –> Sugar+Oxygen)
All living and nonliving matter are made of ________.
elements
An ____ is the smallest unit of matter that exists. They are building blocks for life.
atom
Which three particles are atoms made of?
Protons, neutrons, and electrons.
Each type of atom has a different number of ______.
protons
Atoms join together to form ________.
molecules
Small ________ combine with others to make even larger _________.
molecules, molecules
Everything living and non-living is made of ____ joined together.
atoms
Atoms form _______ by sharing ______ in ___________. These bonds are very strong. They also carry ______.
molecules, electrons, chemical bonds, energy
What is a covalent bond?
Is a chemical bond that involves the sharing of electrons to form electron pairs between atoms.
In water molecules, each __________ atom is bonded to the _________.
hydrogen, oxygen
In water molecules, oxygen and hydrogen share _______ unevenly, so water molecules have __________ on them.
electrons, small charges
What are polar molecules?
Molecules with small charges across them are called polar charges. These molecules have an uneven distribution of charge resulting in one side being positive and the other side negative.
Water molecules ____ together.
stick
In water molecules, the opposite charges are _____ attracted to each other.
weakly
In water molecules, these ____ bonds give water a lot of its _________.
weak, properties
What are hydrogen bonds?
An attraction between two atoms or molecules that already participate in other chemical bonds. (Ex. water molecule being attracted to another water molecule).
True or false: Because water molecules stick together, insects such as water striders can walk on water!
True
Water molecules will also stick to _________.
surfaces
The weak attractions between water molecules also make ______.
ice float
Many substances _______ in water.
dissolve