Lecture 5- Chapter 7: Flashcards
Key Concept 1: Life History
-Life history patterns vary among species and within a species
-Life History events are an adaptation
David Sinclair
- Discovered the cause of death in yeast
- Believes that aging is a disease and that he can cure it
Allocation
- the relative amounts of energy or resources that an organism devotes to different functions
- Can be divided between growth, survival, and reproduction
- Which varies amongst organisms
Frogs Life History
-Is divided between an aquatic stage and a terrestrial one
-Resulting in a several evolutionary decisions
-Life history events are heritable and show variation among species and within
-Duration of tadpole
-Timing of metamorphosis
Frog’s Aquatic Stage
- Egg stage
- Tadpole stage
Frog’s Terrestrial Stage
- Juvenile Stage
- Adult Stage
Genetic and Environmental Differences
-Some frogs lay eggs in freezing cold water temperatures
-Tropical frog breeds within a fluid and keeps its eggs outside of the pond altogether
Phenotypic Plasticity
- May result in a continuous range of sizes, or discrete types called morphs
- Ex. Spadefoot toad is an example of both
- Phenotypic plasticity in timing of metamorphosis
- Tadpoles are the same genotype
- Adult phenotypes differ in side from accelerated
Life Cycle Of a Coral
- Sexual Stage, Juvenile Stage, Adult Stage
1. Meiosis
2. Fertilization
3. Larva
4. Polyp (asexual)
Sexual Stage of a Coral
- meiosis
- fertilization
Juvenile Stage of a Coral
- Larva
- Polyp
Adult Stage of a Coral
- the rest
Key Concept 2 Life History:
- There are trade-offs between life history trait
Key Concept 2 Life History Continued:
There are Trade-offs..
- between the number and size of offspring
- in organisms’ parental care
- between reproduction and survival
Reproductive Sexual Maturity is Reached:
- Energy can be divided between growth or reproduction
- Growth can then stop or continue
Allocation Energy:
- is fixed and can be divided between growth, survival, reproduction, and offspring quality
- Off-spring quality ( many or few)
Parental Care:
- Invest time and energy to feed and protect offspring
- In the tropics, there are higher levels of competition in some areas, if you leave offspring alone, they can be consumed by predators
- Ex. fish, frogs, etc.
Vivid Pairing:
- gives life, and seeds develop into embryos on the plant
- Trade-offs between copulating and survival
Life History Key Concept 3:
- Organisms face different selection pressures at different life cycle stages
The Origin of Life:
- the ocean
- diversity is very high
Crabs:
- have direct development
- most adult crabs are in the Benthic stage
Life Stages:
- Planktonic
- Non Planktonic/ Benthic
Planktonic Life Stage:
- has success
Non-Planktonic/ Benthic:
- do not live over evolutionary time as long as the planktonic ones
Life History Key Concept 4:
- Reproductive patterns can be classified along several continua
- Iteroparous and Semelparous
Iteroparous:
- reproduces multiple times
Semelparous:
- reproduces only once
- Ex. pacific salmon, mayfly
R-selected Species:
- live fast, die young
- Short life spans
- Rapid development
- Early maturation
- Low parental investment
- High reproductive rate
- Ex. insects, small vertebrates such as mice, weedy plant species
K-selected Species:
- Populations that are at or near the carrying capacity for a population (K)
- An advantage in crowded conditions
- Long-lived
- Develop slowly
- Late maturation
- Invest heavily in each offspring
- Low reproduction rates
- Ex. rhinos, tortoise, etc
