Chapter 1: principles of Life Flashcards
Living things are all descended from _______________________(1). All life has a common __________________(2).
(1) A single celled ancestor
(2) ancestry
Living things are all descended from a _____________________(1). All life has a common ___________________(2).
(1) single-celled ancestor
(2) ancestry(descended from a single common ancestor)
What are the characteristics of life?
- Capture energy
- Replicate themselves (reproduction)
- Complex and organized
- Homeostasis
- Grow
- Respond to stimuli, adapt
- Evolve
When did the Earth form?
4.5 billion years ago
When did prokaryotes appear on the Earth? What led to their appearance?
Prokaryotes appeared 3.8 billion years ago. They generated energy living off of heat and radioactivity(uranium decay ). A lipid membrane formed around organic molecules. Prokaryotes could capture energy and replicate.
Chemical evolution led tot he appearance of prokaryotes.
What is chemical evolution?
A theory that suggests the origin of life on Earth. Chemical evolution describes the formation of complex organic molecules from simpler inorganic molecules through chemical reactions in the oceans.
When did photosynthesizing organisms come to Earth? What happened as a result?
2.5 billion years ago
Oxygen concentrations increased in the atmosphere, making aerobic metabolism possible.
What’s the difference between eukaryotes and prokaryotes?
eukaryotes: can be single unicellular (called protists) or multicellular and they always have a nucleus which contains the cell’s genetic material; cell wall can be present or absent
prokaryotes: single celled organisms containing “free floating” genetic material and other biochemical structures in their membrane; they don’t have a nucleus, have cell walls
When did eukaryotic organism form on Earth? How did they form?
1.5 Billion years ago
Prokaryotic cells grew and were able o attach and engulf smaller cells. The smaller cells survived inside and had different functions and pH levels.
What two developments made the evolution of multicellular organisms possible?
- The ability of a cell to change its structure and function to meet the challenges of a changing environment.
- The ability of cells to stick together after they have divided and to act in a coordinated manner.
Once organisms became ________________(1), it became possible for certain cells to _______________(2).
(1) multicellular
(2) specialize
When did the ozone layer form? How did it form and what purpose did it serve?
800 million years ago
Oxygen accumulation led tot eh formation of ozone(O3) in the upper atmosphere.
Ozone is able to prevent UV light from the sun from reaching Earth. Ozone accumulation shielded the landmass from radiation to allow the movement of organisms to land
When did the first land plants form?
450 million years ago
When did the first land animals form?
365 million years ago
When did the first dinosaurs appear on Earth?
230 million years ago
When did the first mammals appear?
200 million years ago
What are multicellular organisms? Did multicellular organisms come before or after eukaryotes?
Multicellular organisms are organisms with more than one cell. Multicellular organisms came after eukaryotes.
What is the internal hierarchy of life?
M - Molecules
M - Macromolecules/Biomolecules
O - Organelles
C - Cells
T - Tissues
O - Organs
O - Organ systems
O - Organism
What is the external hierarchy of life?
Indian - Individual
People - Population
Can’t - Community
Eat - Ecosystems
Beef - Biosphere
What is a population?
A group of organisms of the same species that live in the same area at the same time
What is a community?
Consists of all the populations of different species that live in the same area
What is an ecosystem?
All the biotic and abiotic factors that influence a community
What is a biosphere?
A combination of every ecosystem on the planet. Our biosphere is planet Earth. Includes all living beings and their relationships.
What is the genome?
The complete set of genetic material present in an organism
DNA consists of repeating subunits called _______________(1).
(1) Nucleotides
What is the difference between mammals and reptiles?
mammals: warm blooded(maintain a constant body temperature, typically higher than their surroundings), produce milk, have live births, have hair; have three boned middle ear
Reptiles: Have scales, lay eggs, cold blooded
What do proteins govern in a cell/organism?
Proteins govern chemical reactions in cells and form much of an organisms structure.
What is a gene?
A specific segment of DNA that contains information for making one or more proteins. Genes code for specific traits.
What is the raw material of evolution?
Mutations
What is a genotype?
the combination of alleles that they possess for a specific gene
What is an allele?
An allele is different forms of the same gene(i.e. a vs A)
What is a phenotype?
The set of observable characteristics of an organism
What is the scientific method?
- Make observations
- Ask a question
- Formulate Hypotheses
- Make Predictions
- Design and conduction an experiment to test one of the predictions, Testing
What are the two requirements for a scientific hypotheses?
- Must be testable
- Have the potential of being rejected
Science depends on ______________(1) that comes from _________________(2) and _____________________(3) observations.
(1) evidence
(2) reproducible
(3) quantifiable
